Update specific fields of a widget.

A serializer that conditionally includes optional fields based on context.

Optional fields should be listed in Meta.read_optional_fields. To include them in the output, pass a list via context['include_fields'] (for top-level serializers) or context[<nested_path>]['include_fields'] (for nested serializers).

Examples: class ChildSerializer(IncludeOptionalFieldsSerializerMixin, serializers.ModelSerializer): extra = serializers.CharField() class Meta: model = Child fields = ['id', 'extra'] read_optional_fields = ['extra']

class ParentSerializer(IncludeOptionalFieldsSerializerMixin, serializers.ModelSerializer):
    child = ChildSerializer()
    expensive = serializers.CharField()
    class Meta:
        model = Parent
        fields = ['id', 'child', 'expensive']
        read_optional_fields = ['expensive']

# Top-level usage (includes 'expensive' field)
ParentSerializer(instance, context={'include_fields': ['expensive']}).data

# Nested usage (includes 'extra' field inside child)
ParentSerializer(
    instance,
    context={'child': {'include_fields': ['extra']}}
).data

A serializer that conditionally includes optional fields based on context.

Optional fields should be listed in Meta.read_optional_fields. To include them in the output, pass a list via context['include_fields'] (for top-level serializers) or context[<nested_path>]['include_fields'] (for nested serializers).

Examples: class ChildSerializer(IncludeOptionalFieldsSerializerMixin, serializers.ModelSerializer): extra = serializers.CharField() class Meta: model = Child fields = ['id', 'extra'] read_optional_fields = ['extra']

class ParentSerializer(IncludeOptionalFieldsSerializerMixin, serializers.ModelSerializer):
    child = ChildSerializer()
    expensive = serializers.CharField()
    class Meta:
        model = Parent
        fields = ['id', 'child', 'expensive']
        read_optional_fields = ['expensive']

# Top-level usage (includes 'expensive' field)
ParentSerializer(instance, context={'include_fields': ['expensive']}).data

# Nested usage (includes 'extra' field inside child)
ParentSerializer(
    instance,
    context={'child': {'include_fields': ['extra']}}
).data