Dynamic QuerySet serializer

custom_serializers.py

from rest_framework import serializers

from django.db.models.manager import Manager
from django.db.models.query import QuerySet


class LimitQuerySetSerializerFieldMixin:
    """
    Serializer mixin with a special `get_queryset()` method that lets you pass
    a callable for the queryset kwarg. This enables you to limit the queryset
    based on data or context available on the serializer at runtime.
    """

    def get_queryset(self):
        """
        Return the queryset for a related field. If the queryset is a callable,
        it will be called with one argument which is the field instance and
        should return a queryset or model manager.

        .. code::

            def get_my_limited_queryset(field):
                root = field.root
                if root.instance is None:
                    return MyModel.objects.none()
                return root.instance.related_set.all()

            MySerializer(queryset=get_my_limited_queryset)
        """
        # noinspection PyUnresolvedReferences
        queryset = self.queryset
        if hasattr(queryset, '__call__'):
            queryset = queryset(self)
        if isinstance(queryset, (QuerySet, Manager)):
            # Ensure queryset is re-evaluated whenever used.
            # Note that actually a `Manager` class may also be used as the
            # queryset argument. This occurs on ModelSerializer fields,
            # as it allows us to generate a more expressive 'repr' output
            # for the field.
            # Eg: 'MyRelationship(queryset=ExampleModel.objects.all())'
            queryset = queryset.all()
        return queryset


class DynamicQuersetPrimaryKeyRelatedField(LimitQuerySetSerializerFieldMixin, serializers.PrimaryKeyRelatedField):
    """Evaluates callable queryset at runtime."""
    pass

serializers.py

from rest_framework import serializers
from .custom_serializers import DynamicQuersetPrimaryKeyRelatedField


class MyModelSerializer(serializers.ModelSerializer):
    """
    MyModel serializer with a primary key related field to 'MyRelatedModel'.
    """
    def get_my_limited_queryset(self):
        root = self.root
        if root.instance is None:
            return MyRelatedModel.objects.none()
        return root.instance.related_set.all()
        
    my_related_model = DynamicQuersetPrimaryKeyRelatedField(queryset=get_my_limited_queryset)
    
    class Meta:
        model = MyModel