I'd like to get a single json field in the API response which lists identifiers for related objects based on two reverse foreign key relationships. Simple example what I mean by that is presented below. I'd highly prefer it to be handled on the Django REST Framework serializer level rather than having to change the model in some way, but I have very little DRF experience and I can't for the life of me figure out how to actually do it.
Example models.py:
class Person(models.Model): id = models.AutoField(primary_key=True) first_name = models.CharField(max_length=50, blank=True, null=True) last_name = models.CharField(max_length=50, blank=True, null=True) father = models.ForeignKey("self", related_name="children_as_father", blank=True, null=True, on_delete=models.SET_NULL, ) mother = models.ForeignKey("self", related_name="children_as_mother", blank=True, null=True, on_delete=models.SET_NULL, )Example database data:
| id | first_name | last_name | mother | father |
|---|---|---|---|---|
| 1 | Jane | Smith | ||
| 2 | John | Smith | ||
| 3 | Clarence | Smith | 1 | 2 |
| 4 | Thomas | Smith | 1 | 2 |
Example serialized json I would like to get:
[ {"pk": 1,"first_name": "Jane","last_name": "Smith","mother": null,"father": null,"children": [ 3,4 ], }, {"pk": 2,"first_name": "John","last_name": "Smith","mother": null,"father": null,"children": [ 3,4 ], }, {"pk": 3,"first_name": "Clarence","last_name": "Smith","mother": 1,"father": 2,"children": [], }, {"pk": 4,"first_name": "Thomas","last_name": "Smith","mother": 1,"father": 2,"children": [], }]That's as far as my experiments managed to get, and as you can see compared to example above, it's not quite what I want - I'd like a single json field for children and not two:
serializers.py
from rest_framework.serializers import ModelSerializer, PrimaryKeyRelatedFieldfrom .models import Personclass FamilySerializer(ModelSerializer): children_as_mother = PrimaryKeyRelatedField( many=True, read_only=True, allow_null=True ) children_as_father = PrimaryKeyRelatedField( many=True, read_only=True, allow_null=True ) class Meta: model = Person fields = ["pk","first_name","last_name","mother","father","children_as_mother","children_as_father", ]views.py
from rest_framework.permissions import IsAuthenticatedfrom rest_framework.viewsets import ModelViewSetfrom .models import Personfrom .serializers import FamilySerializerclass FamilyViewSet(ModelViewSet):""" API endpoint with family data""" queryset = Person.objects.all() serializer_class = FamilySerializer permission_classes = [IsAuthenticated]Serialized json:
[ {"pk": 1,"first_name": "Jane","last_name": "Smith","mother": null,"father": null,"children_as_mother": [ 3,4 ],"children_as_father": [], }, {"pk": 2,"first_name": "John","last_name": "Smith","mother": null,"father": null,"children_as_mother": [],"children_as_father": [ 3,4 ], }, {"pk": 3,"first_name": "Clarence","last_name": "Smith","mother": 1,"father": 2,"children_as_mother": [],"children_as_father": [], }, {"pk": 4,"first_name": "Thomas","last_name": "Smith","mother": 1,"father": 2,"children_as_mother": [],"children_as_father": [], }]