limit choices in drop downs in django rest browsable api - django

Question

Is there a way to limit what fields are populated (such as in dropdown selectors or list selectors) in the DRF browsable API?
Below is an image example of how DRF is suggesting choices of "projects" to the user that he should select. However, the logged in user may or may not have access to these projects, so I'd like to get control over what shows up here! It seems that the default behavior is to show all related objects.
It would be really useful if there was a way to link the objects populated in these fields to be set according to a get_queryset() function.
This page seems to hint that it might be possible, I just can't find an example of how to do it: http://www.django-rest-framework.org/api-guide/filtering/

Answer 1

You can define a new field based on some of the serializers.RelatedField-ish classes, and use the request in the context to redefine what the method get_queryset returns.
An example that might work for you:
class AuthorRelatedField(serializers.HyperlinkedRelatedField):
def get_queryset(self):
if 'request' not in self.context:
return Author.objects.none()
request = self.context['request']
return Author.objects.filter(user__pk=request.user.pk)
class BookSerializer(serializers.HyperlinkedModelSerializer):
author = AuthorRelatedField(view_name='author-detail')
Check the templates in DRF/temapltes/rest_framework/inline/select.html. The select object in DRF uses the iter_options method of the field to limit the options in the select tag, which in turn uses the queryset from get_queryset.
This would efectively limit the options of the select tag used in the browsable API. You could filter as well in the get_choices method if you want to preserve the queryset (check the code in DRF/relations.py). I am unsure if this impacts the Admin.

Answer 2

I don't fully understand what do you want but try queryset filter's __in function if you need to show only exact values:
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.
"""
to_show = [ "user1", "user2", "user3"]
queryset = Purchase.objects.all()
username = self.request.query_params.get('username', None)
if username is not None:
queryset = queryset.filter(purchaser__username__in=username)
return queryset
you can add your values to to_show list and if queryset element equals one of them then it will be shown.
Also if you want to show only some fields of model you need to edit your Serializer's fields parameter:
class PurchaseList(serializers.ModelSerializer):
class Meta:
model = Purchase
fields = ('id', 'field1', 'field2', ...)