Module fl_server_api.serializers.model

View Source

# SPDX-FileCopyrightText: 2024 Benedikt Franke <benedikt.franke@dlr.de>
# SPDX-FileCopyrightText: 2024 Florian Heinrich <florian.heinrich@dlr.de>
#
# SPDX-License-Identifier: Apache-2.0

from django.http import HttpRequest
from logging import getLogger
from rest_framework import serializers
from rest_framework.exceptions import ValidationError
from torchinfo import summary
from torchinfo.model_statistics import ModelStatistics
from typing import Any, Dict, List, Optional, Sequence, Tuple, Type

from fl_server_core.models import (
    GlobalModel,
    LocalModel,
    MeanModel,
    Model,
    SWAGModel,
)
from fl_server_core.models.model import TModel
from fl_server_core.utils.torch_serialization import to_torch_module

from ..utils import get_file


def _model_stats_to_dict(stats: ModelStatistics) -> Dict[str, Any]:
    """
    Convert model statistics to a dictionary.

    Args:
        stats (ModelStatistics): The model statistics.

    Returns:
        Dict[str, Any]: The dictionary representation of the model statistics.
    """
    return dict(
        input_size=stats.input_size,
        total_input=stats.total_input,
        total_mult_adds=stats.total_mult_adds,
        total_output_bytes=stats.total_output_bytes,
        total_param_bytes=stats.total_param_bytes,
        total_params=stats.total_params,
        trainable_params=stats.trainable_params,
        summary_list=[
            dict(
                # Metadata
                layer_id=layer.layer_id,
                class_name=layer.class_name,
                depth=layer.depth,
                depth_index=layer.depth_index,
                executed=layer.executed,
                var_name=layer.var_name,
                is_leaf_layer=layer.is_leaf_layer,
                contains_lazy_param=layer.contains_lazy_param,
                # Statistics
                is_recursive=layer.is_recursive,
                input_size=layer.input_size,
                output_size=layer.output_size,
                kernel_size=layer.kernel_size,
                trainable_params=layer.trainable_params,
                num_params=layer.num_params,
                param_bytes=layer.param_bytes,
                output_bytes=layer.output_bytes,
                macs=layer.macs,
            )
            for layer in stats.summary_list
        ],
    )


def _create_model_serializer(cls: Type[TModel], *, name: Optional[str] = None) -> Type[serializers.ModelSerializer]:
    """
    Create a generic Model serializer.

    Args:
        cls (Type[TModel]): Database Model model.
        name (Optional[str], optional): Serializer name. Defaults to `None`.

    Returns:
        Type[serializers.ModelSerializer]: Model model serializer.
    """
    class ModelSerializer(serializers.ModelSerializer):

        class Meta:
            model = cls
            exclude = ["polymorphic_ctype"]

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

    return type(name or f"{cls.__name__}Serializer", (ModelSerializer, ), {})


# Create generic serializers for database model models.
GlobalModelSerializer = _create_model_serializer(GlobalModel)
LocalModelSerializer = _create_model_serializer(LocalModel)
ModelFallbackSerializer = _create_model_serializer(Model, name="ModelFallbackSerializer")

MeanModelSerializer = _create_model_serializer(MeanModel)
SWAGModelSerializer = _create_model_serializer(SWAGModel)


class ModelSerializer(serializers.ModelSerializer):
    """
    A common serializer for the polymorphic Model class.

    The model classes `GlobalModel`, `LocalModel`, `MeanModel`, and `SWAGModel` are supported.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype"]

    @classmethod
    def get_serializer(cls, model: Type[Model]):
        """
        Get the appropriate serializer based on the model type.

        Args:
            model (Type[Model]): The model class.

        Returns:
            Type[serializers.ModelSerializer]: The serializer class for the model.
        """
        if model == GlobalModel:
            return GlobalModelSerializer
        if model == LocalModel:
            return LocalModelSerializer
        if model == MeanModel:
            return MeanModelSerializer
        if model == SWAGModel:
            return SWAGModelSerializer
        getLogger("fl.server").warning(f"Using fallback model serializer for {model.__name__}")
        return ModelFallbackSerializer

    def to_representation(self, instance: Model):
        """
        Generate a dictionary representation of the corresponding model instance.

        Args:
            instance (Model): The Model instance.

        Returns:
            dict: The dictionary representation of the Model instance.
        """
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data


class ModelSerializerNoWeights(ModelSerializer):
    """
    A model serializer that excludes the model weights.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype", "weights"]
        include = ["has_preprocessing"]


class ModelSerializerNoWeightsWithStats(ModelSerializerNoWeights):
    """
    A model serializer that excludes the model weights but includes the model statistics.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype", "weights"]
        include = ["stats"]
        include = ["has_preprocessing", "stats"]


#######################################################################################################################
# POST BODY SERIALIZERS #


def load_and_create_model_request(request: HttpRequest) -> Model:
    """
    Load and create a model from a Django request.

    Args:
        request (HttpRequest): The request object.

    Returns:
        Model: The created model.
    """
    model_cls, data = load_model_request(request)
    if model_cls is MeanModel:
        sub_models = data.pop("models")
        model = model_cls.objects.create(**data)
        model.models.set(sub_models)
        return model
    return model_cls.objects.create(**data)


def load_model_request(request: HttpRequest) -> Tuple[Type[Model], Dict[str, Any]]:
    """
    Load model data from a Django request.

    Args:
        request (HttpRequest): The request object.

    Returns:
        Tuple[Type[Model], Dict[str, Any]]: The model class and parsed request data.
    """
    if request.content_type == "application/json":
        data = request.data
    else:  # multipart/form-data
        data = request.POST.dict()
    data["owner"] = request.user
    model_type = data.pop("type", "GLOBAL").upper()

    # name and description are required
    if "name" not in data:
        raise ValidationError("Missing required field: name")
    if "description" not in data:
        raise ValidationError("Missing required field: description")

    # round is an optional field (it may not even make sense to be able to set it)
    if "round" not in data:
        data["round"] = 0

    # QueryDict removes all "None" entities.
    # Therefore, we need to manually parse the data to dict (the "normal" python way) and get the correct data
    if request.content_type == "application/json":
        data["input_shape"] = dict(request.data).get("input_shape", None)
    else:  # multipart/form-data
        data["input_shape"] = dict(request.POST).get("input_shape", None)
    # input_shape contains None as String but this is not parseable to a nullable int later -> parsing
    if "input_shape" in data:
        if data["input_shape"] is None:
            # nothing to do
            pass
        elif isinstance(data["input_shape"], str) and data["input_shape"].upper() in ["NONE", "NULL"]:
            data["input_shape"] = None
        elif not isinstance(data["input_shape"], Sequence):
            data["input_shape"] = None
        elif len(data["input_shape"]) < 1:
            data["input_shape"] = None
        else:
            data["input_shape"] = [None if str(x).upper() in ["NONE", "NULL"] else x for x in data["input_shape"]]

    # model_file is required except for MEAN models
    if model_type != "MEAN":
        data["weights"] = get_file(request, "model_file")
        verify_model_object(data["weights"])

    # model_preprocessing_file is optional
    data["preprocessing"] = None
    if request.FILES.__contains__("model_preprocessing_file"):
        data["preprocessing"] = get_file(request, "model_preprocessing_file")
        verify_model_object(data["preprocessing"], "preprocessing")

    # MEAN models require a list of model UUIDs
    if model_type == "MEAN":
        data = _parse_mean_model_models(data)

    # return class type and parsed data
    match model_type:
        case "SWAG": return SWAGModel, data
        case "MEAN": return MeanModel, data
        case _: return GlobalModel, data


def verify_model_object(model: bytes, file_type_name: str = "model") -> None:
    """
    Verify the model object.

    Args:
        model (bytes): The model object.
        file_type_name (str, optional): The file type name. Defaults to "model".

    Raises:
        ValidationError: If the model object is invalid.
    """
    try:
        to_torch_module(model)
    except Exception as e:
        raise ValidationError(f"Invalid {file_type_name} file: {e}") from e


def _parse_mean_model_models(data: Dict[str, Any]) -> Dict[str, Any]:
    """
    Parse the models field of a mean model request.

    Args:
        data (Dict[str, Any]): The request data.

    Returns:
        Dict[str, Any]: The parsed request data.

    Raises:
        ValidationError: If the models field is missing or invalid.
    """
    if "models" not in data:
        raise ValidationError("Missing required field: models")
    models = data["models"]
    if not isinstance(models, list) or not all([isinstance(m, str) for m in models]):
        raise ValidationError("Invalid type for field: models")
    data["models"] = Model.objects.filter(id__in=models)
    if data["models"].count() != len(models):
        raise ValidationError("Invalid model UUIDs found.")
    if not all([m.owner.id == data["owner"].id for m in data["models"]]):
        raise ValidationError("Invalid model selection. Insufficient model permissions.")
    return data

Functions

load_and_create_model_request

def load_and_create_model_request(
    request: django.http.request.HttpRequest
) -> fl_server_core.models.model.Model

Load and create a model from a Django request.

Parameters:

Name	Type	Description	Default
request	HttpRequest	The request object.	None

Returns:

Type	Description
Model	The created model.

View Source

def load_and_create_model_request(request: HttpRequest) -> Model:
    """
    Load and create a model from a Django request.

    Args:
        request (HttpRequest): The request object.

    Returns:
        Model: The created model.
    """
    model_cls, data = load_model_request(request)
    if model_cls is MeanModel:
        sub_models = data.pop("models")
        model = model_cls.objects.create(**data)
        model.models.set(sub_models)
        return model
    return model_cls.objects.create(**data)

load_model_request

def load_model_request(
    request: django.http.request.HttpRequest
) -> Tuple[Type[fl_server_core.models.model.Model], Dict[str, Any]]

Load model data from a Django request.

Parameters:

Name	Type	Description	Default
request	HttpRequest	The request object.	None

Returns:

Type	Description
Tuple[Type[Model], Dict[str, Any]]	The model class and parsed request data.

View Source

def load_model_request(request: HttpRequest) -> Tuple[Type[Model], Dict[str, Any]]:
    """
    Load model data from a Django request.

    Args:
        request (HttpRequest): The request object.

    Returns:
        Tuple[Type[Model], Dict[str, Any]]: The model class and parsed request data.
    """
    if request.content_type == "application/json":
        data = request.data
    else:  # multipart/form-data
        data = request.POST.dict()
    data["owner"] = request.user
    model_type = data.pop("type", "GLOBAL").upper()

    # name and description are required
    if "name" not in data:
        raise ValidationError("Missing required field: name")
    if "description" not in data:
        raise ValidationError("Missing required field: description")

    # round is an optional field (it may not even make sense to be able to set it)
    if "round" not in data:
        data["round"] = 0

    # QueryDict removes all "None" entities.
    # Therefore, we need to manually parse the data to dict (the "normal" python way) and get the correct data
    if request.content_type == "application/json":
        data["input_shape"] = dict(request.data).get("input_shape", None)
    else:  # multipart/form-data
        data["input_shape"] = dict(request.POST).get("input_shape", None)
    # input_shape contains None as String but this is not parseable to a nullable int later -> parsing
    if "input_shape" in data:
        if data["input_shape"] is None:
            # nothing to do
            pass
        elif isinstance(data["input_shape"], str) and data["input_shape"].upper() in ["NONE", "NULL"]:
            data["input_shape"] = None
        elif not isinstance(data["input_shape"], Sequence):
            data["input_shape"] = None
        elif len(data["input_shape"]) < 1:
            data["input_shape"] = None
        else:
            data["input_shape"] = [None if str(x).upper() in ["NONE", "NULL"] else x for x in data["input_shape"]]

    # model_file is required except for MEAN models
    if model_type != "MEAN":
        data["weights"] = get_file(request, "model_file")
        verify_model_object(data["weights"])

    # model_preprocessing_file is optional
    data["preprocessing"] = None
    if request.FILES.__contains__("model_preprocessing_file"):
        data["preprocessing"] = get_file(request, "model_preprocessing_file")
        verify_model_object(data["preprocessing"], "preprocessing")

    # MEAN models require a list of model UUIDs
    if model_type == "MEAN":
        data = _parse_mean_model_models(data)

    # return class type and parsed data
    match model_type:
        case "SWAG": return SWAGModel, data
        case "MEAN": return MeanModel, data
        case _: return GlobalModel, data

verify_model_object

def verify_model_object(
    model: bytes,
    file_type_name: str = 'model'
) -> None

Verify the model object.

Parameters:

Name	Type	Description	Default
model	bytes	The model object.	None
file_type_name	str	The file type name. Defaults to "model".	"model"

Raises:

Type	Description
ValidationError	If the model object is invalid.

View Source

def verify_model_object(model: bytes, file_type_name: str = "model") -> None:
    """
    Verify the model object.

    Args:
        model (bytes): The model object.
        file_type_name (str, optional): The file type name. Defaults to "model".

    Raises:
        ValidationError: If the model object is invalid.
    """
    try:
        to_torch_module(model)
    except Exception as e:
        raise ValidationError(f"Invalid {file_type_name} file: {e}") from e

Classes

GlobalModelSerializer

class GlobalModelSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A ModelSerializer is just a regular Serializer, except that:

• A set of default fields are automatically populated.
• A set of default validators are automatically populated.
• Default .create() and .update() implementations are provided.

The process of automatically determining a set of serializer fields based on the model fields is reasonably complex, but you almost certainly don't need to dig into the implementation.

If the ModelSerializer class doesn't generate the set of fields that you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a Serializer class.

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

analyze_torch_model

def analyze_torch_model(
    self,
    instance: fl_server_core.models.model.Model
)

View Source

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance
)

View Source

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

LocalModelSerializer

class LocalModelSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A ModelSerializer is just a regular Serializer, except that:

• A set of default fields are automatically populated.
• A set of default validators are automatically populated.
• Default .create() and .update() implementations are provided.

The process of automatically determining a set of serializer fields based on the model fields is reasonably complex, but you almost certainly don't need to dig into the implementation.

If the ModelSerializer class doesn't generate the set of fields that you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a Serializer class.

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

analyze_torch_model

def analyze_torch_model(
    self,
    instance: fl_server_core.models.model.Model
)

View Source

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance
)

View Source

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

MeanModelSerializer

class MeanModelSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A ModelSerializer is just a regular Serializer, except that:

• A set of default fields are automatically populated.
• A set of default validators are automatically populated.
• Default .create() and .update() implementations are provided.

The process of automatically determining a set of serializer fields based on the model fields is reasonably complex, but you almost certainly don't need to dig into the implementation.

If the ModelSerializer class doesn't generate the set of fields that you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a Serializer class.

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

analyze_torch_model

def analyze_torch_model(
    self,
    instance: fl_server_core.models.model.Model
)

View Source

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance
)

View Source

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

ModelFallbackSerializer

class ModelFallbackSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A ModelSerializer is just a regular Serializer, except that:

• A set of default fields are automatically populated.
• A set of default validators are automatically populated.
• Default .create() and .update() implementations are provided.

The process of automatically determining a set of serializer fields based on the model fields is reasonably complex, but you almost certainly don't need to dig into the implementation.

If the ModelSerializer class doesn't generate the set of fields that you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a Serializer class.

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

analyze_torch_model

def analyze_torch_model(
    self,
    instance: fl_server_core.models.model.Model
)

View Source

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance
)

View Source

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

ModelSerializer

class ModelSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A common serializer for the polymorphic Model class.

The model classes GlobalModel, LocalModel, MeanModel, and SWAGModel are supported.

View Source

class ModelSerializer(serializers.ModelSerializer):
    """
    A common serializer for the polymorphic Model class.

    The model classes `GlobalModel`, `LocalModel`, `MeanModel`, and `SWAGModel` are supported.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype"]

    @classmethod
    def get_serializer(cls, model: Type[Model]):
        """
        Get the appropriate serializer based on the model type.

        Args:
            model (Type[Model]): The model class.

        Returns:
            Type[serializers.ModelSerializer]: The serializer class for the model.
        """
        if model == GlobalModel:
            return GlobalModelSerializer
        if model == LocalModel:
            return LocalModelSerializer
        if model == MeanModel:
            return MeanModelSerializer
        if model == SWAGModel:
            return SWAGModelSerializer
        getLogger("fl.server").warning(f"Using fallback model serializer for {model.__name__}")
        return ModelFallbackSerializer

    def to_representation(self, instance: Model):
        """
        Generate a dictionary representation of the corresponding model instance.

        Args:
            instance (Model): The Model instance.

        Returns:
            dict: The dictionary representation of the Model instance.
        """
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data

---

Ancestors (in MRO)

• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Descendants

• fl_server_api.serializers.model.ModelSerializerNoWeights

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

get_serializer

def get_serializer(
    model: Type[fl_server_core.models.model.Model]
)

Get the appropriate serializer based on the model type.

Parameters:

Name	Type	Description	Default
model	Type[Model]	The model class.	None

Returns:

Type	Description
Type[serializers.ModelSerializer]	The serializer class for the model.

View Source

    @classmethod
    def get_serializer(cls, model: Type[Model]):
        """
        Get the appropriate serializer based on the model type.

        Args:
            model (Type[Model]): The model class.

        Returns:
            Type[serializers.ModelSerializer]: The serializer class for the model.
        """
        if model == GlobalModel:
            return GlobalModelSerializer
        if model == LocalModel:
            return LocalModelSerializer
        if model == MeanModel:
            return MeanModelSerializer
        if model == SWAGModel:
            return SWAGModelSerializer
        getLogger("fl.server").warning(f"Using fallback model serializer for {model.__name__}")
        return ModelFallbackSerializer

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance: fl_server_core.models.model.Model
)

Generate a dictionary representation of the corresponding model instance.

Parameters:

Name	Type	Description	Default
instance	Model	The Model instance.	None

Returns:

Type	Description
dict	The dictionary representation of the Model instance.

View Source

    def to_representation(self, instance: Model):
        """
        Generate a dictionary representation of the corresponding model instance.

        Args:
            instance (Model): The Model instance.

        Returns:
            dict: The dictionary representation of the Model instance.
        """
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

ModelSerializerNoWeights

class ModelSerializerNoWeights(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A model serializer that excludes the model weights.

View Source

class ModelSerializerNoWeights(ModelSerializer):
    """
    A model serializer that excludes the model weights.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype", "weights"]
        include = ["has_preprocessing"]

---

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Descendants

• fl_server_api.serializers.model.ModelSerializerNoWeightsWithStats

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

get_serializer

def get_serializer(
    model: Type[fl_server_core.models.model.Model]
)

Get the appropriate serializer based on the model type.

Parameters:

Name	Type	Description	Default
model	Type[Model]	The model class.	None

Returns:

Type	Description
Type[serializers.ModelSerializer]	The serializer class for the model.

View Source

    @classmethod
    def get_serializer(cls, model: Type[Model]):
        """
        Get the appropriate serializer based on the model type.

        Args:
            model (Type[Model]): The model class.

        Returns:
            Type[serializers.ModelSerializer]: The serializer class for the model.
        """
        if model == GlobalModel:
            return GlobalModelSerializer
        if model == LocalModel:
            return LocalModelSerializer
        if model == MeanModel:
            return MeanModelSerializer
        if model == SWAGModel:
            return SWAGModelSerializer
        getLogger("fl.server").warning(f"Using fallback model serializer for {model.__name__}")
        return ModelFallbackSerializer

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance: fl_server_core.models.model.Model
)

Generate a dictionary representation of the corresponding model instance.

Parameters:

Name	Type	Description	Default
instance	Model	The Model instance.	None

Returns:

Type	Description
dict	The dictionary representation of the Model instance.

View Source

    def to_representation(self, instance: Model):
        """
        Generate a dictionary representation of the corresponding model instance.

        Args:
            instance (Model): The Model instance.

        Returns:
            dict: The dictionary representation of the Model instance.
        """
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

ModelSerializerNoWeightsWithStats

class ModelSerializerNoWeightsWithStats(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A model serializer that excludes the model weights but includes the model statistics.

View Source

class ModelSerializerNoWeightsWithStats(ModelSerializerNoWeights):
    """
    A model serializer that excludes the model weights but includes the model statistics.
    """

    class Meta:
        model = Model
        exclude = ["polymorphic_ctype", "weights"]
        include = ["stats"]
        include = ["has_preprocessing", "stats"]

---

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializerNoWeights
• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

get_serializer

def get_serializer(
    model: Type[fl_server_core.models.model.Model]
)

Get the appropriate serializer based on the model type.

Parameters:

Name	Type	Description	Default
model	Type[Model]	The model class.	None

Returns:

Type	Description
Type[serializers.ModelSerializer]	The serializer class for the model.

View Source

    @classmethod
    def get_serializer(cls, model: Type[Model]):
        """
        Get the appropriate serializer based on the model type.

        Args:
            model (Type[Model]): The model class.

        Returns:
            Type[serializers.ModelSerializer]: The serializer class for the model.
        """
        if model == GlobalModel:
            return GlobalModelSerializer
        if model == LocalModel:
            return LocalModelSerializer
        if model == MeanModel:
            return MeanModelSerializer
        if model == SWAGModel:
            return SWAGModelSerializer
        getLogger("fl.server").warning(f"Using fallback model serializer for {model.__name__}")
        return ModelFallbackSerializer

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance: fl_server_core.models.model.Model
)

Generate a dictionary representation of the corresponding model instance.

Parameters:

Name	Type	Description	Default
instance	Model	The Model instance.	None

Returns:

Type	Description
dict	The dictionary representation of the Model instance.

View Source

    def to_representation(self, instance: Model):
        """
        Generate a dictionary representation of the corresponding model instance.

        Args:
            instance (Model): The Model instance.

        Returns:
            dict: The dictionary representation of the Model instance.
        """
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)

SWAGModelSerializer

class SWAGModelSerializer(
    instance=None,
    data=<class 'rest_framework.fields.empty'>,
    **kwargs
)

A ModelSerializer is just a regular Serializer, except that:

• A set of default fields are automatically populated.
• A set of default validators are automatically populated.
• Default .create() and .update() implementations are provided.

The process of automatically determining a set of serializer fields based on the model fields is reasonably complex, but you almost certainly don't need to dig into the implementation.

If the ModelSerializer class doesn't generate the set of fields that you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a Serializer class.

Ancestors (in MRO)

• fl_server_api.serializers.model.ModelSerializer
• rest_framework.serializers.ModelSerializer
• rest_framework.serializers.Serializer
• rest_framework.serializers.BaseSerializer
• rest_framework.fields.Field

Class variables

Meta

default_empty_html

default_error_messages

default_validators

initial

serializer_choice_field

serializer_field_mapping

serializer_related_field

serializer_related_to_field

serializer_url_field

url_field_name

Static methods

many_init

def many_init(
    *args,
    **kwargs
)

This method implements the creation of a ListSerializer parent

class when many=True is used. You can customize it if you need to control which keyword arguments are passed to the parent, and which are passed to the child.

Note that we're over-cautious in passing most arguments to both parent and child classes in order to try to cover the general case. If you're overriding this method you'll probably want something much simpler, eg:

@classmethod def many_init(cls, args, kwargs): kwargs['child'] = cls() return CustomListSerializer(args, **kwargs)

View Source

    @classmethod
    def many_init(cls, *args, **kwargs):
        """
        This method implements the creation of a `ListSerializer` parent
        class when `many=True` is used. You can customize it if you need to
        control which keyword arguments are passed to the parent, and
        which are passed to the child.

        Note that we're over-cautious in passing most arguments to both parent
        and child classes in order to try to cover the general case. If you're
        overriding this method you'll probably want something much simpler, eg:

        @classmethod
        def many_init(cls, *args, **kwargs):
            kwargs['child'] = cls()
            return CustomListSerializer(*args, **kwargs)
        """
        allow_empty = kwargs.pop('allow_empty', None)
        max_length = kwargs.pop('max_length', None)
        min_length = kwargs.pop('min_length', None)
        child_serializer = cls(*args, **kwargs)
        list_kwargs = {
            'child': child_serializer,
        }
        if allow_empty is not None:
            list_kwargs['allow_empty'] = allow_empty
        if max_length is not None:
            list_kwargs['max_length'] = max_length
        if min_length is not None:
            list_kwargs['min_length'] = min_length
        list_kwargs.update({
            key: value for key, value in kwargs.items()
            if key in LIST_SERIALIZER_KWARGS
        })
        meta = getattr(cls, 'Meta', None)
        list_serializer_class = getattr(meta, 'list_serializer_class', ListSerializer)
        return list_serializer_class(*args, **list_kwargs)

Instance variables

context

Returns the context as passed to the root serializer on initialization.

data

errors

root

Returns the top-level serializer for this field.

validated_data

validators

Methods

analyze_torch_model

def analyze_torch_model(
    self,
    instance: fl_server_core.models.model.Model
)

View Source

        def analyze_torch_model(self, instance: Model):
            if not isinstance(instance, GlobalModel) or not instance.input_shape:
                return None
            # try to analyze the model stats
            try:
                torch_model = instance.get_torch_model()
                input_shape: List[int] = [1 if x is None else x for x in instance.input_shape]
                stats = summary(torch_model, input_size=input_shape, verbose=0)
                return _model_stats_to_dict(stats)
            except Exception as e:
                getLogger("fl.server").warning(f"Failed to analyze model {instance.id}: {e}")
            return None

bind

def bind(
    self,
    field_name,
    parent
)

Initializes the field name and parent for the field instance.

Called when a field is added to the parent serializer instance.

View Source

    def bind(self, field_name, parent):
        """
        Initializes the field name and parent for the field instance.
        Called when a field is added to the parent serializer instance.
        """

        # In order to enforce a consistent style, we error if a redundant
        # 'source' argument has been used. For example:
        # my_field = serializer.CharField(source='my_field')
        assert self.source != field_name, (
            "It is redundant to specify `source='%s'` on field '%s' in "
            "serializer '%s', because it is the same as the field name. "
            "Remove the `source` keyword argument." %
            (field_name, self.__class__.__name__, parent.__class__.__name__)
        )

        self.field_name = field_name
        self.parent = parent

        # `self.label` should default to being based on the field name.
        if self.label is None:
            self.label = field_name.replace('_', ' ').capitalize()

        # self.source should default to being the same as the field name.
        if self.source is None:
            self.source = field_name

        # self.source_attrs is a list of attributes that need to be looked up
        # when serializing the instance, or populating the validated data.
        if self.source == '*':
            self.source_attrs = []
        else:
            self.source_attrs = self.source.split('.')

build_field

def build_field(
    self,
    field_name,
    info,
    model_class,
    nested_depth
)

Return a two tuple of (cls, kwargs) to build a serializer field with.

View Source

    def build_field(self, field_name, info, model_class, nested_depth):
        """
        Return a two tuple of (cls, kwargs) to build a serializer field with.
        """
        if field_name in info.fields_and_pk:
            model_field = info.fields_and_pk[field_name]
            return self.build_standard_field(field_name, model_field)

        elif field_name in info.relations:
            relation_info = info.relations[field_name]
            if not nested_depth:
                return self.build_relational_field(field_name, relation_info)
            else:
                return self.build_nested_field(field_name, relation_info, nested_depth)

        elif hasattr(model_class, field_name):
            return self.build_property_field(field_name, model_class)

        elif field_name == self.url_field_name:
            return self.build_url_field(field_name, model_class)

        return self.build_unknown_field(field_name, model_class)

build_nested_field

def build_nested_field(
    self,
    field_name,
    relation_info,
    nested_depth
)

Create nested fields for forward and reverse relationships.

View Source

    def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(ModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1
                fields = '__all__'

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs

build_property_field

def build_property_field(
    self,
    field_name,
    model_class
)

Create a read only field for model methods and properties.

View Source

    def build_property_field(self, field_name, model_class):
        """
        Create a read only field for model methods and properties.
        """
        field_class = ReadOnlyField
        field_kwargs = {}

        return field_class, field_kwargs

build_relational_field

def build_relational_field(
    self,
    field_name,
    relation_info
)

Create fields for forward and reverse relationships.

View Source

    def build_relational_field(self, field_name, relation_info):
        """
        Create fields for forward and reverse relationships.
        """
        field_class = self.serializer_related_field
        field_kwargs = get_relation_kwargs(field_name, relation_info)

        to_field = field_kwargs.pop('to_field', None)
        if to_field and not relation_info.reverse and not relation_info.related_model._meta.get_field(to_field).primary_key:
            field_kwargs['slug_field'] = to_field
            field_class = self.serializer_related_to_field

        # `view_name` is only valid for hyperlinked relationships.
        if not issubclass(field_class, HyperlinkedRelatedField):
            field_kwargs.pop('view_name', None)

        return field_class, field_kwargs

build_standard_field

def build_standard_field(
    self,
    field_name,
    model_field
)

Create regular model fields.

View Source

    def build_standard_field(self, field_name, model_field):
        """
        Create regular model fields.
        """
        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        # Special case to handle when a OneToOneField is also the primary key
        if model_field.one_to_one and model_field.primary_key:
            field_class = self.serializer_related_field
            field_kwargs['queryset'] = model_field.related_model.objects

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = {
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            }
            for key in list(field_kwargs):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        is_django_jsonfield = hasattr(models, 'JSONField') and isinstance(model_field, models.JSONField)
        if (postgres_fields and isinstance(model_field, postgres_fields.JSONField)) or is_django_jsonfield:
            # Populate the `encoder` argument of `JSONField` instances generated
            # for the model `JSONField`.
            field_kwargs['encoder'] = getattr(model_field, 'encoder', None)
            if is_django_jsonfield:
                field_kwargs['decoder'] = getattr(model_field, 'decoder', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgreSQL specific `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs

build_unknown_field

def build_unknown_field(
    self,
    field_name,
    model_class
)

Raise an error on any unknown fields.

View Source

    def build_unknown_field(self, field_name, model_class):
        """
        Raise an error on any unknown fields.
        """
        raise ImproperlyConfigured(
            'Field name `%s` is not valid for model `%s`.' %
            (field_name, model_class.__name__)
        )

build_url_field

def build_url_field(
    self,
    field_name,
    model_class
)

Create a field representing the object's own URL.

View Source

    def build_url_field(self, field_name, model_class):
        """
        Create a field representing the object's own URL.
        """
        field_class = self.serializer_url_field
        field_kwargs = get_url_kwargs(model_class)

        return field_class, field_kwargs

create

def create(
    self,
    validated_data
)

We have a bit of extra checking around this in order to provide

descriptive messages when something goes wrong, but this method is essentially just:

return ExampleModel.objects.create(**validated_data)

If there are many to many fields present on the instance then they cannot be set until the model is instantiated, in which case the implementation is like so:

example_relationship = validated_data.pop('example_relationship')
instance = ExampleModel.objects.create(**validated_data)
instance.example_relationship = example_relationship
return instance

The default implementation also does not handle nested relationships. If you want to support writable nested relationships you'll need to write an explicit .create() method.

View Source

    def create(self, validated_data):
        """
        We have a bit of extra checking around this in order to provide
        descriptive messages when something goes wrong, but this method is
        essentially just:

            return ExampleModel.objects.create(**validated_data)

        If there are many to many fields present on the instance then they
        cannot be set until the model is instantiated, in which case the
        implementation is like so:

            example_relationship = validated_data.pop('example_relationship')
            instance = ExampleModel.objects.create(**validated_data)
            instance.example_relationship = example_relationship
            return instance

        The default implementation also does not handle nested relationships.
        If you want to support writable nested relationships you'll need
        to write an explicit `.create()` method.
        """
        raise_errors_on_nested_writes('create', self, validated_data)

        ModelClass = self.Meta.model

        # Remove many-to-many relationships from validated_data.
        # They are not valid arguments to the default `.create()` method,
        # as they require that the instance has already been saved.
        info = model_meta.get_field_info(ModelClass)
        many_to_many = {}
        for field_name, relation_info in info.relations.items():
            if relation_info.to_many and (field_name in validated_data):
                many_to_many[field_name] = validated_data.pop(field_name)

        try:
            instance = ModelClass._default_manager.create(**validated_data)
        except TypeError:
            tb = traceback.format_exc()
            msg = (
                'Got a `TypeError` when calling `%s.%s.create()`. '
                'This may be because you have a writable field on the '
                'serializer class that is not a valid argument to '
                '`%s.%s.create()`. You may need to make the field '
                'read-only, or override the %s.create() method to handle '
                'this correctly.\nOriginal exception was:\n %s' %
                (
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    ModelClass.__name__,
                    ModelClass._default_manager.name,
                    self.__class__.__name__,
                    tb
                )
            )
            raise TypeError(msg)

        # Save many-to-many relationships after the instance is created.
        if many_to_many:
            for field_name, value in many_to_many.items():
                field = getattr(instance, field_name)
                field.set(value)

        return instance

fail

def fail(
    self,
    key,
    **kwargs
)

A helper method that simply raises a validation error.

View Source

    def fail(self, key, **kwargs):
        """
        A helper method that simply raises a validation error.
        """
        try:
            msg = self.error_messages[key]
        except KeyError:
            class_name = self.__class__.__name__
            msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
            raise AssertionError(msg)
        message_string = msg.format(**kwargs)
        raise ValidationError(message_string, code=key)

fields

def fields(
    ...
)

A dictionary of {field_name: field_instance}.

get_attribute

def get_attribute(
    self,
    instance
)

Given the outgoing object instance, return the primitive value

that should be used for this field.

View Source

    def get_attribute(self, instance):
        """
        Given the *outgoing* object instance, return the primitive value
        that should be used for this field.
        """
        try:
            return get_attribute(instance, self.source_attrs)
        except BuiltinSignatureError as exc:
            msg = (
                'Field source for `{serializer}.{field}` maps to a built-in '
                'function type and is invalid. Define a property or method on '
                'the `{instance}` instance that wraps the call to the built-in '
                'function.'.format(
                    serializer=self.parent.__class__.__name__,
                    field=self.field_name,
                    instance=instance.__class__.__name__,
                )
            )
            raise type(exc)(msg)
        except (KeyError, AttributeError) as exc:
            if self.default is not empty:
                return self.get_default()
            if self.allow_null:
                return None
            if not self.required:
                raise SkipField()
            msg = (
                'Got {exc_type} when attempting to get a value for field '
                '`{field}` on serializer `{serializer}`.\nThe serializer '
                'field might be named incorrectly and not match '
                'any attribute or key on the `{instance}` instance.\n'
                'Original exception text was: {exc}.'.format(
                    exc_type=type(exc).__name__,
                    field=self.field_name,
                    serializer=self.parent.__class__.__name__,
                    instance=instance.__class__.__name__,
                    exc=exc
                )
            )
            raise type(exc)(msg)

get_default

def get_default(
    self
)

Return the default value to use when validating data if no input

is provided for this field.

If a default has not been set for this field then this will simply raise SkipField, indicating that no value should be set in the validated data for this field.

View Source

    def get_default(self):
        """
        Return the default value to use when validating data if no input
        is provided for this field.

        If a default has not been set for this field then this will simply
        raise `SkipField`, indicating that no value should be set in the
        validated data for this field.
        """
        if self.default is empty or getattr(self.root, 'partial', False):
            # No default, or this is a partial update.
            raise SkipField()
        if callable(self.default):
            if getattr(self.default, 'requires_context', False):
                return self.default(self)
            else:
                return self.default()

        return self.default

get_default_field_names

def get_default_field_names(
    self,
    declared_fields,
    model_info
)

Return the default list of field names that will be used if the

Meta.fields option is not specified.

View Source

    def get_default_field_names(self, declared_fields, model_info):
        """
        Return the default list of field names that will be used if the
        `Meta.fields` option is not specified.
        """
        return (
            [model_info.pk.name] +
            list(declared_fields) +
            list(model_info.fields) +
            list(model_info.forward_relations)
        )

get_extra_kwargs

def get_extra_kwargs(
    self
)

Return a dictionary mapping field names to a dictionary of

additional keyword arguments.

View Source

    def get_extra_kwargs(self):
        """
        Return a dictionary mapping field names to a dictionary of
        additional keyword arguments.
        """
        extra_kwargs = copy.deepcopy(getattr(self.Meta, 'extra_kwargs', {}))

        read_only_fields = getattr(self.Meta, 'read_only_fields', None)
        if read_only_fields is not None:
            if not isinstance(read_only_fields, (list, tuple)):
                raise TypeError(
                    'The `read_only_fields` option must be a list or tuple. '
                    'Got %s.' % type(read_only_fields).__name__
                )
            for field_name in read_only_fields:
                kwargs = extra_kwargs.get(field_name, {})
                kwargs['read_only'] = True
                extra_kwargs[field_name] = kwargs

        else:
            # Guard against the possible misspelling `readonly_fields` (used
            # by the Django admin and others).
            assert not hasattr(self.Meta, 'readonly_fields'), (
                'Serializer `%s.%s` has field `readonly_fields`; '
                'the correct spelling for the option is `read_only_fields`.' %
                (self.__class__.__module__, self.__class__.__name__)
            )

        return extra_kwargs

get_field_names

def get_field_names(
    self,
    declared_fields,
    info
)

Returns the list of all field names that should be created when

instantiating this serializer class. This is based on the default set of fields, but also takes into account the Meta.fields or Meta.exclude options if they have been specified.

View Source

    def get_field_names(self, declared_fields, info):
        """
        Returns the list of all field names that should be created when
        instantiating this serializer class. This is based on the default
        set of fields, but also takes into account the `Meta.fields` or
        `Meta.exclude` options if they have been specified.
        """
        fields = getattr(self.Meta, 'fields', None)
        exclude = getattr(self.Meta, 'exclude', None)

        if fields and fields != ALL_FIELDS and not isinstance(fields, (list, tuple)):
            raise TypeError(
                'The `fields` option must be a list or tuple or "__all__". '
                'Got %s.' % type(fields).__name__
            )

        if exclude and not isinstance(exclude, (list, tuple)):
            raise TypeError(
                'The `exclude` option must be a list or tuple. Got %s.' %
                type(exclude).__name__
            )

        assert not (fields and exclude), (
            "Cannot set both 'fields' and 'exclude' options on "
            "serializer {serializer_class}.".format(
                serializer_class=self.__class__.__name__
            )
        )

        assert not (fields is None and exclude is None), (
            "Creating a ModelSerializer without either the 'fields' attribute "
            "or the 'exclude' attribute has been deprecated since 3.3.0, "
            "and is now disallowed. Add an explicit fields = '__all__' to the "
            "{serializer_class} serializer.".format(
                serializer_class=self.__class__.__name__
            ),
        )

        if fields == ALL_FIELDS:
            fields = None

        if fields is not None:
            # Ensure that all declared fields have also been included in the
            # `Meta.fields` option.

            # Do not require any fields that are declared in a parent class,
            # in order to allow serializer subclasses to only include
            # a subset of fields.
            required_field_names = set(declared_fields)
            for cls in self.__class__.__bases__:
                required_field_names -= set(getattr(cls, '_declared_fields', []))

            for field_name in required_field_names:
                assert field_name in fields, (
                    "The field '{field_name}' was declared on serializer "
                    "{serializer_class}, but has not been included in the "
                    "'fields' option.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
            return fields

        # Use the default set of field names if `Meta.fields` is not specified.
        fields = self.get_default_field_names(declared_fields, info)

        if exclude is not None:
            # If `Meta.exclude` is included, then remove those fields.
            for field_name in exclude:
                assert field_name not in self._declared_fields, (
                    "Cannot both declare the field '{field_name}' and include "
                    "it in the {serializer_class} 'exclude' option. Remove the "
                    "field or, if inherited from a parent serializer, disable "
                    "with `{field_name} = None`."
                    .format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )

                assert field_name in fields, (
                    "The field '{field_name}' was included on serializer "
                    "{serializer_class} in the 'exclude' option, but does "
                    "not match any model field.".format(
                        field_name=field_name,
                        serializer_class=self.__class__.__name__
                    )
                )
                fields.remove(field_name)

        return fields

get_fields

def get_fields(
    self
)

Return the dict of field names -> field instances that should be

used for self.fields when instantiating the serializer.

View Source

    def get_fields(self):
        """
        Return the dict of field names -> field instances that should be
        used for `self.fields` when instantiating the serializer.
        """
        if self.url_field_name is None:
            self.url_field_name = api_settings.URL_FIELD_NAME

        assert hasattr(self, 'Meta'), (
            'Class {serializer_class} missing "Meta" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        assert hasattr(self.Meta, 'model'), (
            'Class {serializer_class} missing "Meta.model" attribute'.format(
                serializer_class=self.__class__.__name__
            )
        )
        if model_meta.is_abstract_model(self.Meta.model):
            raise ValueError(
                'Cannot use ModelSerializer with Abstract Models.'
            )

        declared_fields = copy.deepcopy(self._declared_fields)
        model = getattr(self.Meta, 'model')
        depth = getattr(self.Meta, 'depth', 0)

        if depth is not None:
            assert depth >= 0, "'depth' may not be negative."
            assert depth <= 10, "'depth' may not be greater than 10."

        # Retrieve metadata about fields & relationships on the model class.
        info = model_meta.get_field_info(model)
        field_names = self.get_field_names(declared_fields, info)

        # Determine any extra field arguments and hidden fields that
        # should be included
        extra_kwargs = self.get_extra_kwargs()
        extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs(
            field_names, declared_fields, extra_kwargs
        )

        # Determine the fields that should be included on the serializer.
        fields = OrderedDict()

        for field_name in field_names:
            # If the field is explicitly declared on the class then use that.
            if field_name in declared_fields:
                fields[field_name] = declared_fields[field_name]
                continue

            extra_field_kwargs = extra_kwargs.get(field_name, {})
            source = extra_field_kwargs.get('source', '*')
            if source == '*':
                source = field_name

            # Determine the serializer field class and keyword arguments.
            field_class, field_kwargs = self.build_field(
                source, info, model, depth
            )

            # Include any kwargs defined in `Meta.extra_kwargs`
            field_kwargs = self.include_extra_kwargs(
                field_kwargs, extra_field_kwargs
            )

            # Create the serializer field.
            fields[field_name] = field_class(**field_kwargs)

        # Add in any hidden fields.
        fields.update(hidden_fields)

        return fields

get_initial

def get_initial(
    self
)

Return a value to use when the field is being returned as a primitive

value, without any object instance.

View Source

    def get_initial(self):
        if hasattr(self, 'initial_data'):
            # initial_data may not be a valid type
            if not isinstance(self.initial_data, Mapping):
                return OrderedDict()

            return OrderedDict([
                (field_name, field.get_value(self.initial_data))
                for field_name, field in self.fields.items()
                if (field.get_value(self.initial_data) is not empty) and
                not field.read_only
            ])

        return OrderedDict([
            (field.field_name, field.get_initial())
            for field in self.fields.values()
            if not field.read_only
        ])

get_unique_for_date_validators

def get_unique_for_date_validators(
    self
)

Determine a default set of validators for the following constraints:

• unique_for_date
• unique_for_month
• unique_for_year

View Source

    def get_unique_for_date_validators(self):
        """
        Determine a default set of validators for the following constraints:

        * unique_for_date
        * unique_for_month
        * unique_for_year
        """
        info = model_meta.get_field_info(self.Meta.model)
        default_manager = self.Meta.model._default_manager
        field_names = [field.source for field in self.fields.values()]

        validators = []

        for field_name, field in info.fields_and_pk.items():
            if field.unique_for_date and field_name in field_names:
                validator = UniqueForDateValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_date
                )
                validators.append(validator)

            if field.unique_for_month and field_name in field_names:
                validator = UniqueForMonthValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_month
                )
                validators.append(validator)

            if field.unique_for_year and field_name in field_names:
                validator = UniqueForYearValidator(
                    queryset=default_manager,
                    field=field_name,
                    date_field=field.unique_for_year
                )
                validators.append(validator)

        return validators

get_unique_together_validators

def get_unique_together_validators(
    self
)

Determine a default set of validators for any unique_together constraints.

View Source

    def get_unique_together_validators(self):
        """
        Determine a default set of validators for any unique_together constraints.
        """
        model_class_inheritance_tree = (
            [self.Meta.model] +
            list(self.Meta.model._meta.parents)
        )

        # The field names we're passing though here only include fields
        # which may map onto a model field. Any dotted field name lookups
        # cannot map to a field, and must be a traversal, so we're not
        # including those.
        field_sources = OrderedDict(
            (field.field_name, field.source) for field in self._writable_fields
            if (field.source != '*') and ('.' not in field.source)
        )

        # Special Case: Add read_only fields with defaults.
        field_sources.update(OrderedDict(
            (field.field_name, field.source) for field in self.fields.values()
            if (field.read_only) and (field.default != empty) and (field.source != '*') and ('.' not in field.source)
        ))

        # Invert so we can find the serializer field names that correspond to
        # the model field names in the unique_together sets. This also allows
        # us to check that multiple fields don't map to the same source.
        source_map = defaultdict(list)
        for name, source in field_sources.items():
            source_map[source].append(name)

        # Note that we make sure to check `unique_together` both on the
        # base model class, but also on any parent classes.
        validators = []
        for parent_class in model_class_inheritance_tree:
            for unique_together in parent_class._meta.unique_together:
                # Skip if serializer does not map to all unique together sources
                if not set(source_map).issuperset(unique_together):
                    continue

                for source in unique_together:
                    assert len(source_map[source]) == 1, (
                        "Unable to create `UniqueTogetherValidator` for "
                        "`{model}.{field}` as `{serializer}` has multiple "
                        "fields ({fields}) that map to this model field. "
                        "Either remove the extra fields, or override "
                        "`Meta.validators` with a `UniqueTogetherValidator` "
                        "using the desired field names."
                        .format(
                            model=self.Meta.model.__name__,
                            serializer=self.__class__.__name__,
                            field=source,
                            fields=', '.join(source_map[source]),
                        )
                    )

                field_names = tuple(source_map[f][0] for f in unique_together)
                validator = UniqueTogetherValidator(
                    queryset=parent_class._default_manager,
                    fields=field_names
                )
                validators.append(validator)
        return validators

get_uniqueness_extra_kwargs

def get_uniqueness_extra_kwargs(
    self,
    field_names,
    declared_fields,
    extra_kwargs
)

Return any additional field options that need to be included as a

result of uniqueness constraints on the model. This is returned as a two-tuple of:

('dict of updated extra kwargs', 'mapping of hidden fields')

View Source

    def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs):
        """
        Return any additional field options that need to be included as a
        result of uniqueness constraints on the model. This is returned as
        a two-tuple of:

        ('dict of updated extra kwargs', 'mapping of hidden fields')
        """
        if getattr(self.Meta, 'validators', None) is not None:
            return (extra_kwargs, {})

        model = getattr(self.Meta, 'model')
        model_fields = self._get_model_fields(
            field_names, declared_fields, extra_kwargs
        )

        # Determine if we need any additional `HiddenField` or extra keyword
        # arguments to deal with `unique_for` dates that are required to
        # be in the input data in order to validate it.
        unique_constraint_names = set()

        for model_field in model_fields.values():
            # Include each of the `unique_for_*` field names.
            unique_constraint_names |= {model_field.unique_for_date, model_field.unique_for_month,
                                        model_field.unique_for_year}

        unique_constraint_names -= {None}

        # Include each of the `unique_together` field names,
        # so long as all the field names are included on the serializer.
        for parent_class in [model] + list(model._meta.parents):
            for unique_together_list in parent_class._meta.unique_together:
                if set(field_names).issuperset(unique_together_list):
                    unique_constraint_names |= set(unique_together_list)

        # Now we have all the field names that have uniqueness constraints
        # applied, we can add the extra 'required=...' or 'default=...'
        # arguments that are appropriate to these fields, or add a `HiddenField` for it.
        hidden_fields = {}
        uniqueness_extra_kwargs = {}

        for unique_constraint_name in unique_constraint_names:
            # Get the model field that is referred too.
            unique_constraint_field = model._meta.get_field(unique_constraint_name)

            if getattr(unique_constraint_field, 'auto_now_add', None):
                default = CreateOnlyDefault(timezone.now)
            elif getattr(unique_constraint_field, 'auto_now', None):
                default = timezone.now
            elif unique_constraint_field.has_default():
                default = unique_constraint_field.default
            else:
                default = empty

            if unique_constraint_name in model_fields:
                # The corresponding field is present in the serializer
                if default is empty:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'required': True}
                else:
                    uniqueness_extra_kwargs[unique_constraint_name] = {'default': default}
            elif default is not empty:
                # The corresponding field is not present in the
                # serializer. We have a default to use for it, so
                # add in a hidden field that populates it.
                hidden_fields[unique_constraint_name] = HiddenField(default=default)

        # Update `extra_kwargs` with any new options.
        for key, value in uniqueness_extra_kwargs.items():
            if key in extra_kwargs:
                value.update(extra_kwargs[key])
            extra_kwargs[key] = value

        return extra_kwargs, hidden_fields

get_validators

def get_validators(
    self
)

Determine the set of validators to use when instantiating serializer.

View Source

    def get_validators(self):
        """
        Determine the set of validators to use when instantiating serializer.
        """
        # If the validators have been declared explicitly then use that.
        validators = getattr(getattr(self, 'Meta', None), 'validators', None)
        if validators is not None:
            return list(validators)

        # Otherwise use the default set of validators.
        return (
            self.get_unique_together_validators() +
            self.get_unique_for_date_validators()
        )

get_value

def get_value(
    self,
    dictionary
)

Given the incoming primitive data, return the value for this field

that should be validated and transformed to a native value.

View Source

    def get_value(self, dictionary):
        # We override the default field access in order to support
        # nested HTML forms.
        if html.is_html_input(dictionary):
            return html.parse_html_dict(dictionary, prefix=self.field_name) or empty
        return dictionary.get(self.field_name, empty)

include_extra_kwargs

def include_extra_kwargs(
    self,
    kwargs,
    extra_kwargs
)

Include any 'extra_kwargs' that have been included for this field,

possibly removing any incompatible existing keyword arguments.

View Source

    def include_extra_kwargs(self, kwargs, extra_kwargs):
        """
        Include any 'extra_kwargs' that have been included for this field,
        possibly removing any incompatible existing keyword arguments.
        """
        if extra_kwargs.get('read_only', False):
            for attr in [
                'required', 'default', 'allow_blank', 'min_length',
                'max_length', 'min_value', 'max_value', 'validators', 'queryset'
            ]:
                kwargs.pop(attr, None)

        if extra_kwargs.get('default') and kwargs.get('required') is False:
            kwargs.pop('required')

        if extra_kwargs.get('read_only', kwargs.get('read_only', False)):
            extra_kwargs.pop('required', None)  # Read only fields should always omit the 'required' argument.

        kwargs.update(extra_kwargs)

        return kwargs

is_valid

def is_valid(
    self,
    *,
    raise_exception=False
)

View Source

    def is_valid(self, *, raise_exception=False):
        assert hasattr(self, 'initial_data'), (
            'Cannot call `.is_valid()` as no `data=` keyword argument was '
            'passed when instantiating the serializer instance.'
        )

        if not hasattr(self, '_validated_data'):
            try:
                self._validated_data = self.run_validation(self.initial_data)
            except ValidationError as exc:
                self._validated_data = {}
                self._errors = exc.detail
            else:
                self._errors = {}

        if self._errors and raise_exception:
            raise ValidationError(self.errors)

        return not bool(self._errors)

run_validation

def run_validation(
    self,
    data=<class 'rest_framework.fields.empty'>
)

We override the default run_validation, because the validation

performed by validators and the .validate() method should be coerced into an error dictionary with a 'non_fields_error' key.

View Source

    def run_validation(self, data=empty):
        """
        We override the default `run_validation`, because the validation
        performed by validators and the `.validate()` method should
        be coerced into an error dictionary with a 'non_fields_error' key.
        """
        (is_empty_value, data) = self.validate_empty_values(data)
        if is_empty_value:
            return data

        value = self.to_internal_value(data)
        try:
            self.run_validators(value)
            value = self.validate(value)
            assert value is not None, '.validate() should return the validated data'
        except (ValidationError, DjangoValidationError) as exc:
            raise ValidationError(detail=as_serializer_error(exc))

        return value

run_validators

def run_validators(
    self,
    value
)

Add read_only fields with defaults to value before running validators.

View Source

    def run_validators(self, value):
        """
        Add read_only fields with defaults to value before running validators.
        """
        if isinstance(value, dict):
            to_validate = self._read_only_defaults()
            to_validate.update(value)
        else:
            to_validate = value
        super().run_validators(to_validate)

save

def save(
    self,
    **kwargs
)

View Source

    def save(self, **kwargs):
        assert hasattr(self, '_errors'), (
            'You must call `.is_valid()` before calling `.save()`.'
        )

        assert not self.errors, (
            'You cannot call `.save()` on a serializer with invalid data.'
        )

        # Guard against incorrect use of `serializer.save(commit=False)`
        assert 'commit' not in kwargs, (
            "'commit' is not a valid keyword argument to the 'save()' method. "
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
            "You can also pass additional keyword arguments to 'save()' if you "
            "need to set extra attributes on the saved model instance. "
            "For example: 'serializer.save(owner=request.user)'.'"
        )

        assert not hasattr(self, '_data'), (
            "You cannot call `.save()` after accessing `serializer.data`."
            "If you need to access data before committing to the database then "
            "inspect 'serializer.validated_data' instead. "
        )

        validated_data = {**self.validated_data, **kwargs}

        if self.instance is not None:
            self.instance = self.update(self.instance, validated_data)
            assert self.instance is not None, (
                '`update()` did not return an object instance.'
            )
        else:
            self.instance = self.create(validated_data)
            assert self.instance is not None, (
                '`create()` did not return an object instance.'
            )

        return self.instance

to_internal_value

def to_internal_value(
    self,
    data
)

Dict of native values <- Dict of primitive datatypes.

View Source

    def to_internal_value(self, data):
        """
        Dict of native values <- Dict of primitive datatypes.
        """
        if not isinstance(data, Mapping):
            message = self.error_messages['invalid'].format(
                datatype=type(data).__name__
            )
            raise ValidationError({
                api_settings.NON_FIELD_ERRORS_KEY: [message]
            }, code='invalid')

        ret = OrderedDict()
        errors = OrderedDict()
        fields = self._writable_fields

        for field in fields:
            validate_method = getattr(self, 'validate_' + field.field_name, None)
            primitive_value = field.get_value(data)
            try:
                validated_value = field.run_validation(primitive_value)
                if validate_method is not None:
                    validated_value = validate_method(validated_value)
            except ValidationError as exc:
                errors[field.field_name] = exc.detail
            except DjangoValidationError as exc:
                errors[field.field_name] = get_error_detail(exc)
            except SkipField:
                pass
            else:
                set_value(ret, field.source_attrs, validated_value)

        if errors:
            raise ValidationError(errors)

        return ret

to_representation

def to_representation(
    self,
    instance
)

View Source

        def to_representation(self, instance):
            # only return the whole model (weights) if requested
            data = serializers.ModelSerializer.to_representation(self, instance)
            if not self.context.get("with-weights", False):
                del data["weights"]
            if self.context.get("with-stats", False):
                data["stats"] = self.analyze_torch_model(instance)
            if isinstance(instance, GlobalModel):
                data["has_preprocessing"] = bool(instance.preprocessing)
            return data

update

def update(
    self,
    instance,
    validated_data
)

View Source

    def update(self, instance, validated_data):
        raise_errors_on_nested_writes('update', self, validated_data)
        info = model_meta.get_field_info(instance)

        # Simply set each attribute on the instance, and then save it.
        # Note that unlike `.create()` we don't need to treat many-to-many
        # relationships as being a special case. During updates we already
        # have an instance pk for the relationships to be associated with.
        m2m_fields = []
        for attr, value in validated_data.items():
            if attr in info.relations and info.relations[attr].to_many:
                m2m_fields.append((attr, value))
            else:
                setattr(instance, attr, value)

        instance.save()

        # Note that many-to-many fields are set after updating instance.
        # Setting m2m fields triggers signals which could potentially change
        # updated instance and we do not want it to collide with .update()
        for attr, value in m2m_fields:
            field = getattr(instance, attr)
            field.set(value)

        return instance

validate

def validate(
    self,
    attrs
)

View Source

    def validate(self, attrs):
        return attrs

validate_empty_values

def validate_empty_values(
    self,
    data
)

Validate empty values, and either:

• Raise ValidationError, indicating invalid data.
• Raise SkipField, indicating that the field should be ignored.
• Return (True, data), indicating an empty value that should be returned without any further validation being applied.
• Return (False, data), indicating a non-empty value, that should have validation applied as normal.

View Source

    def validate_empty_values(self, data):
        """
        Validate empty values, and either:

        * Raise `ValidationError`, indicating invalid data.
        * Raise `SkipField`, indicating that the field should be ignored.
        * Return (True, data), indicating an empty value that should be
          returned without any further validation being applied.
        * Return (False, data), indicating a non-empty value, that should
          have validation applied as normal.
        """
        if self.read_only:
            return (True, self.get_default())

        if data is empty:
            if getattr(self.root, 'partial', False):
                raise SkipField()
            if self.required:
                self.fail('required')
            return (True, self.get_default())

        if data is None:
            if not self.allow_null:
                self.fail('null')
            # Nullable `source='*'` fields should not be skipped when its named
            # field is given a null value. This is because `source='*'` means
            # the field is passed the entire object, which is not null.
            elif self.source == '*':
                return (False, None)
            return (True, None)

        return (False, data)