Combine two django models with shared ids into a single viewset

I have two django models in two independent apps, who use the same user ids from an external authentication service:

In app1/models.py:

class App1User(models.Model):

    user_id = models.UUIDField(unique=True)
    app1_field = models.BooleanField()

In app2/models.py:

class App2User(models.Model):

    user_id = models.UUIDField(unique=True)
    app2_field = models.BooleanField()

I would like to have a combined viewset that can make it seem like these two are a single model with a list response as follows:

[
	{
		'user_id': ...,
		'app1_field': ...,
		'app2_field': ...
	},
	...
]

If I create or update with this viewset, it should save the data to each of the two models.

> To create a combined viewset for App1User and App2User models, you can
> follow these steps:
>
> Create a serializer for the combined model. In your main app, create a
> serializers.py file and define the following serializer:

from rest_framework import serializers
from app1.models import App1User
from app2.models import App2User

class App1UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = App1User
        fields = ('user_id', 'app1_field')

class App2UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = App2User
        fields = ('user_id', 'app2_field')

class CombinedUserSerializer(serializers.Serializer):
    user_id = serializers.UUIDField()
    app1_field = serializers.BooleanField()
    app2_field = serializers.BooleanField()

def create(self, validated_data):
    app1_data = {'user_id': validated_data['user_id'], 'app1_field': validated_data['app1_field']}
    app2_data = {'user_id': validated_data['user_id'], 'app2_field': validated_data['app2_field']}
    app1_serializer = App1UserSerializer(data=app1_data)
    app2_serializer = App2UserSerializer(data=app2_data)
    if app1_serializer.is_valid() and app2_serializer.is_valid():
        app1_serializer.save()
        app2_serializer.save()
    return validated_data

def update(self, instance, validated_data):
    app1_instance = App1User.objects.get(user_id=validated_data['user_id'])
    app2_instance = App2User.objects.get(user_id=validated_data['user_id'])
    app1_serializer = App1UserSerializer(app1_instance, data={'app1_field': validated_data['app1_field']})
    app2_serializer = App2UserSerializer(app2_instance, data={'app2_field': validated_data['app2_field']})
    if app1_serializer.is_valid() and app2_serializer.is_valid():
        app1_serializer.save()
        app2_serializer.save()
    return validated_data

This serializer defines the structure of the combined model and uses App1UserSerializer and App2UserSerializer to handle the fields of each model.

> 2. Create a viewset for the combined model. In your main app, create a viewsets.py file and define the following viewset:

from rest_framework import viewsets
from app1.models import App1User
from app2.models import App2User
from .serializers import CombinedUserSerializer

class CombinedUserViewSet(viewsets.ModelViewSet):
    serializer_class = CombinedUserSerializer

    def get_queryset(self):
        app1_users = App1User.objects.all()
        app2_users = App2User.objects.all()
        combined_users = []
        for app1_user in app1_users:
            app2_user = app2_users.filter(user_id=app1_user.user_id).first()
            if app2_user:
                combined_user = {
                    'user_id': app1_user.user_id,
                    'app1_field': app1_user.app1_field,
                    'app2_field': app2_user.app2_field
                }
                combined_users.append(combined_user)
        return combined_users

This viewset uses CombinedUserSerializer to handle the requests and retrieves the data from both App1User and App2User models. The get_queryset() method retrieves all the App1User and App2User instances, matches them based on their user_id, and creates a list of combined users.

> 3. Register the viewset in your main app's urls.py file:

# main_app/urls.py

from django.urls import include, path
from rest_framework import routers
from .views import CombinedUserViewSet

router = routers.DefaultRouter()
router.register(r'combined-users', CombinedUserViewSet)

urlpatterns = [
    path('', include(router.urls)),
]

This code sets up a default router and registers the CombinedUserViewSet with the endpoint /combined-users/, which can be used to access the combined model data.

Above solution is the idea how it can be done, you can modify according to your needs. If this idea helps, plz mark this as accept solution.