In Django Rest Framework, how do handle invalid filtering parameters?

Question

I want to limit the queryset returned by a ListAPIView, using the filtering technique described here.

The question is, how do I handle invalid parameters? Raising a ValidationError only works for serializers, not within the ViewSet. I'd like to let the user know that the request was invalid, rather than failing silently.

For example:

class PurchaseList(generics.ListAPIView):
    serializer_class = PurchaseSerializer

    def get_queryset(self):
        queryset = Purchase.objects.all()
        username = self.request.query_params.get('username', None)
        if username is not None:
              try:
                  user = User.objects.get(username=username)
              except User.DoesNotExist:
                  # How do I handle this invalid parameter?
              else:
                  queryset = queryset.filter(purchaser=user)
        return queryset

petkostas · Accepted Answer · 2015-07-16 10:42:35Z

5

Use the build in exceptions, since you are responding for something that was not found, use the NotFound:

from rest_framework import exceptions

class PurchaseList(generics.ListAPIView):
    serializer_class = PurchaseSerializer

    def get_queryset(self):
        queryset = Purchase.objects.all()
        username = self.request.query_params.get('username', None)
        if username is not None:
              try:
                  user = User.objects.get(username=username)
              except User.DoesNotExist:
                  raise exceptions.NotFound(detail="Some message if you want")
              else:
                  return queryset.filter(purchaser=user)
        return queryset

answered Jul 16, 2015 at 10:42

petkostas

7,4903 gold badges29 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Akshar Raaj · Accepted Answer · 2015-07-16 10:50:14Z

1

Can't you just return an empty list?

queryset = queryset.filter(purchaser__username=username)

If it is an invalid username this queryset will just be an empty queryset and DRF will return an empty list in result.

answered Jul 16, 2015 at 10:50

Akshar Raaj

15.4k7 gold badges54 silver badges46 bronze badges

1 Comment

seddonym Over a year ago

This question is about letting the user know that the request was invalid, rather than failing silently.

Collectives™ on Stack Overflow

In Django Rest Framework, how do handle invalid filtering parameters?

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related