Django REST framework light includable serializer fields

Requirements

• Python (2.7, 3.4, 3.5, 3.6)
• Django REST Framework (>=3.0)

Usage

serializers.py

class GroupSerializer(SerializerIncludeMixin, ModelSerializer):
    @classproperty  # django.utils.decorators
    def extra_objects(cls):
        return {
            'users': UserSerializer(source='user_set', many=True),
            'active_users': UserSerializer(many=True),
        }

    class Meta:
        model = Group
        fields = ('id', 'name')

views.py

class GroupViewSet(QueryOptimizerMixin, ReadOnlyModelViewSet):
    """
    Groups.

    list:
    Available includable objects:

      * users - all users;
      * active_users - only active users.
    """
    queryset = Group.objects.all()
    serializer_class = GroupSerializer
    select_related = {}
    prefetch_related = {
        'users': 'user_set',
        'active_users': Prefetch(
            lookup='user_set',
            queryset=User.objects.filter(is_active=True),
            to_attr='active_users',
        ),
    }

And now we can to do that:

client = APIClient()
response = client.get(  # GET /groups/?include[]=active_users
    '/groups/',
    data=[
        ('include[]', 'active_users'),
    ],
)

This will make only 2 query:

• all groups
• prefetch only active users

Documentation

rest_framework_include_mixin.SerializerIncludeMixin

Used in any serializer to automatically replace and add serializer fields.

extra_objects class variable

key:str - value from GET parameter include[]. For example, profile for /users/?include[]=profile.

value:Serializer - any field serializer.

Example:

class UserSerializer(SerializerIncludeMixin, ModelSerializer):
    extra_objects =  {
        'profile': ProfileSerializer(),
        'groups': GroupSerializer(many=True),
    }

    class Meta:
        model = User
        fields = ('id', 'profile_id')

Note: standard serializer fields with/without _id will be replaced to field from extra_objects.

For ?include[]=profile: profile and profile_id will be replaced to profile from extra_objects.

rest_framework_include_mixin.QueryOptimizerMixin

Used with ModelViewSet to optimize database queries.

select_related class variable

key:str - value from GET parameter include[].

value:str - field name that can be passed to select_related (model manager function).

prefetch_related class variable

key:str - value from GET parameter include[].

value:Union[str, Prefetch] - field name or Prefetch object that can be passed to prefetch_related (model manager function).