Merge queryset from two databases in Django Rest - django

Question

I have two routes in my api looking like that :
http://mywebsite/websites/website_1/annonces/
http://mywebsite/websites/website_2/annonces/
I need to make an ListAPIView merging these 2 routes but each route call its own database.
The two databases are made with the same django Model. I made two databases because it suits my architecture better.
The problem is that I have no column in my databases which indicates the website the records are from. The records are only differentiated by the names of their database.
I want to get all record in a single route but also being able to tell from which database they are from in the json response.
class Annonce(models.Model):
annonce_type = models.CharField(max_length=200, blank=True, null=True)
annonce_id = models.CharField(unique=True, max_length=200, blank=True, null=True)
url = models.TextField(blank=True, null=True)
region = models.TextField(blank=True, null=True)
class AnnoncesList(generics.ListAPIView):
authentication_classes = ()
permission_classes = ()
serializer_class = AnnonceListSerializer
pagination_class = LargeResultsSetPagination
filter_backends = (DjangoFilterBackend,)
filterset_fields = ('advert_type', 'asset_type', 'sales_type', 'price', 'area', 'department', 'department_id', 'city', 'postal_code')
def get_queryset(self):
queryset = Annonce.objects.using(self.kwargs["website_name"]).all()
return queryset

Answer 1

Make the queryset for each database, then use annotate() to add a column website_name for each record on queryset. Concatenate the querysets into a list (check this) (will hit all items on database), make sure the querysets have already been properly filtered.
from itertools import chain
from rest_framework.generics import ListAPIView
from rest_framework.response import Response
from django.db.models import Value, CharField
class AnnonceMergedList(ListAPIView):
serializer_class = AnnonceMergedListSerializer
queryset = Annonce.objects.all()
def list(self, request, **kwargs):
# Make the querysets for each database
q1 = self.get_queryset().using('website_1').annotate(website_name=Value('website_1', CharField()))
q2 = self.get_queryset().using('website_2').annotate(website_name=Value('website_2', CharField()))
# Filtering the querysets
q1 = self.filter_queryset(q1)
q2 = self.filter_queryset(q2)
# Merge (hit items on database)
data = list(chain(q1, q2))
serializer = self.get_serializer(data, many=True)
return Response(serializer.data)
The serializer for this view must receive the website_name to display the website the records are from
class AnnonceMergedListSerializer(serializers.ModelSerializer):
website_name = serializers.CharField(read_only=True) # Field from annotation
class Meta:
model = Annonce
fields = ('website_name', ...)