How to properly return error when overriding .get_queryset()?

Question

I read on DRF doc that you can filter againt query parameters by overriding .get_queryset(). I am looking for the best practice, on what to return, in case the filters are incorrect and where to return an error message.

The doc I referred to is here And I include the source code below

class PurchaseList(generics.ListAPIView):
    serializer_class = PurchaseSerializer

    def get_queryset(self):
        """
        Optionally restricts the returned purchases to a given user,
        by filtering against a `username` query parameter in the URL.
        """
        queryset = Purchase.objects.all()
        username = self.request.query_params.get('username', None)
        if username is not None:
            queryset = queryset.filter(purchaser__username=username)
        return queryset

Thank you for your help

Answer 1

You can do this

from rest_framework import status

class PurchaseList(generics.ListAPIView):
    serializer_class = PurchaseSerializer
    def get_queryset(self):
        try:
            """
            Optionally restricts the returned purchases to a given user,
            by filtering against a username query parameter in the URL.
            """
            queryset = Purchase.objects.all()
            username = self.request.query_params.get('username', None)
            if username is not None:
                    queryset = queryset.filter(purchaser__username=username)
            return queryset
        except:
            return None

    def get(self, request):
        try:
           data=view_serializer(self.get_queryset(),many=True).data
           context = {
               "data" : data,
               "message" : "Contents returned successfully",
               "success" : True
               }
           return Response(context, status=status.HTTP_200_OK)
        except Exception as error:
           context = {'error': str(error), 'success': "false", 'message': 'Failed To Get contents.'}
           return Response(context, status=status.HTTP_500_INTERNAL_SERVER_ERROR)