Enabling all fields filtering by default

[filipetavares]

I'm opening this issue to ask if this if statement is required, since if you remove it you will enable all fields to be filtered upon as long as you define the DEFAULT_BACKEND_FILTER in your settings.py.

django-url-filter/url_filter/integrations/drf.py

Lines 93 to 104 in 1585da8

	if filter_fields:
	model = filter_class_default.filter_backend_class(queryset).get_model()
	meta_kwargs = filter_class_meta_kwargs.copy()
	meta_kwargs.update({"model": model, "fields": filter_fields})
	meta = type(str("Meta"), (object,), meta_kwargs)
	return type(
	str("{}FilterSet".format(model.__name__)),
	(filter_class_default,),
	{"Meta": meta},
	)

From what I've read on the docs, this should be the default behaviour, but it doesn't work on GenericAPIViews, because if I don't define some fieldset_fields on the view it won't generate a filterset class since the condition above will fail.

For context, this is my view:

class UsersView(GenericAPIView):

    queryset = User.objects.all()
    serializer_class = UserSerializer
    permission_classes = [IsAuthenticated]


    def get_queryset(self):
        return self.filter_queryset(super().get_queryset())

    def get(self, request):

        serializer = self.get_serializer(self.get_queryset(), many=True)
        return Response(data=serializer.data, status=status.HTTP_200_OK )

and these are my settings:

REST_FRAMEWORK = {
  ...
    'DEFAULT_FILTER_BACKENDS': [
        'url_filter.integrations.drf.DjangoFilterBackend',
    ]
}

By default is doesn't filter by any field, but if I remove only the if statement (line 93) it works fine.

So am I setting something wrong, or is this an actual bug?