Cant handle a response error on django-rest-framework - error-handling

Question

I am trying to return 400 bad requets response when a user with a company created tries to create another one on my API
I tried with a Response but it does not work, it seems that it does not enter on the if
class CompanyViewSet(generics.ListCreateAPIView):
serializer_class = CompanySerializer
permission_classes = [permissions.IsAuthenticated]
def get_queryset(self):
return UserCompany.objects.filter(owner=self.request.user.id)
def perform_create(self, serializer):
queryset = UserCompany.objects.filter(owner=self.request.user.id)
if queryset.exists():
content = {'API response error:': 'Can have only a one company for every user'}
return Response(content, status=status.HTTP_400_BAD_REQUEST)
else:
serializer.save(owner=self.request.user)
When I create a company in user that already has one returns state 200 but don't create it, I expected it to return state 400

Answer 1

Because perform_create only save serializer . If you want control status response, you should override create. Try like this:
def create(self, request, *args, **kwargs):
queryset = UserCompany.objects.filter(owner=self.request.user.id)
if queryset.exists():
content = {'API response error:': 'Can have only a one company for every user'}
return Response(content, status=status.HTTP_400_BAD_REQUEST)
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)