Multiple lookup_fields for django rest framework

Question

I have multiple API which historically work using id as the lookup field:

/api/organization/10

I have a frontend consuming tho

Answer 1

Try this

from django.db.models import Q
import operator
class MultipleFieldLookupMixin(object):
    def get_object(self):
        queryset = self.get_queryset()             # Get the base queryset
        queryset = self.filter_queryset(queryset)  # Apply any filter backends
        filter = {}
        for field in self.lookup_fields:
            filter[field] = self.kwargs[field]
        q = reduce(operator.or_, (Q(x) for x in filter.items()))
        return get_object_or_404(queryset, q)

Then in View

class Organization(MultipleFieldLookupMixin, viewsets.ModelViewSet):
    queryset = OrganisationGroup.objects.all()
    serializer_class = OrganizationSerializer
    lookup_fields = ('pk', 'another field')

Hope this helps.

Answer 2

I think the fundamental answer is that this would not be good REST/API design and just isn't something DRF would enable.

Answer 3

I solved the similar problem by overriding retrieve method and check pk field's value against any pattern. For example if it consists of only numbers.

def retrieve(self, request, *args, **kwargs):
    if kwargs['pk'].isdigit():
        return super(Organization, self).retrieve(request, *args, **kwargs)
    else:
        # get and return object however you want here.

Answer 4

class MultipleFieldLookupMixin(object):
    """
    Apply this mixin to any view or viewset to get multiple field filtering
    based on a `lookup_fields` attribute, instead of the default single field filtering.
    """

    def get_object(self):
        queryset = self.get_queryset()  # Get the base queryset
        queryset = self.filter_queryset(queryset)
        filter = {}
        for field in self.lookup_fields:
            if self.kwargs[field]:  # Ignore empty fields.
                filter[field] = self.kwargs[field]
        return get_object_or_404(queryset, **filter)  # Lookup the object


class RetrieveUserView(MultipleFieldLookupMixin, generics.RetrieveAPIView):
    queryset = User.objects.all()
    serializer_class = UserSerializer
    lookup_fields = ('account', 'username')

Answer 5

The official docs have an example for this at https://www.django-rest-framework.org/api-guide/generic-views/#creating-custom-mixins

Also, you need to modify the urls.py adding a new route for the same view, but with the new field name.

Answer 6

There are a lot of answers here already, but none provide a full description including the mixin, view, and url configuration. This answer does.

This is the mixin that works best, it is slightly modified from https://www.django-rest-framework.org/api-guide/generic-views/#creating-custom-mixins to not error out on non-existing fields.

class MultipleFieldLookupMixin:
    """
    Apply this mixin to any view or viewset to get multiple field filtering
    based on a `lookup_fields` attribute, instead of the default single field filtering.

    Source: https://www.django-rest-framework.org/api-guide/generic-views/#creating-custom-mixins
    Modified to not error out for not providing all fields in the url.
    """

    def get_object(self):
        queryset = self.get_queryset()             # Get the base queryset
        queryset = self.filter_queryset(queryset)  # Apply any filter backends
        filter = {}
        for field in self.lookup_fields:
            if self.kwargs.get(field):  # Ignore empty fields.
                filter[field] = self.kwargs[field]
        obj = get_object_or_404(queryset, **filter)  # Lookup the object
        self.check_object_permissions(self.request, obj)
        return obj

Now add the view as follows, it is important to have the Mixin first, otherwise the get_object method is not overwritten:

class RudAPIView(MultipleFieldLookupMixin, generics.RetrieveUpdateDestroyAPIView):
    ...
    lookup_fields = ['pk', 'other_field']

Now, for the urls, we use default converters. It is important int comes first as that one will actually check if it is an int, and if not fallback to str. If you have more complex fields, you need to resort to regex.

path('efficiency/<int:pk>/', views.RudAPIView.as_view(), name='something-rud'),
path('efficiency/<string:other_field>/', views.RudAPIView.as_view(), name='something-rud'),