Is a lookup field required in a routers `detail_route`?

Question

Looking over here: http://www.django-rest-framework.org/api-guide/routers/#extra-link-and-actions The example has pk=None:

@detail_route(methods=['post'], permission_classes=[IsAdminOrIsSelf])
def set_password(self, request, pk=None):

and says the following url pattern will be generated: ^users/{pk}/set_password/$

Over here: http://www.django-rest-framework.org/api-guide/routers/#simplerouter It also says that lookup field is in the url: {prefix}/{lookup}/{methodname}/

Does DRF pass the lookup value to the detail_route method? Based on the documentation, it looks like it does, but over here: http://www.django-rest-framework.org/api-guide/routers/#example

If you scroll down to:

@detail_route()
    def group_names(self, request):
        """
        Returns a list of all the group names that the given
        user belongs to.
        """
        user = self.get_object()
        groups = user.groups.all()
        return Response([group.name for group in groups])

A lookup value is not asked for as an argument to the group_names function. My questions are:

1) Is pk / a lookup field argument required in a detail_route?

2) If not, then how does self.get_object() know which object to get?

3) Also, if not, then shouldn't @list_route be used instead since a lookup is not even being used?

Edit: Over here: http://www.django-rest-framework.org/api-guide/viewsets/#marking-extra-actions-for-routing It also says The @detail_route decorator contains pk in its URL pattern and is intended for methods which require a single instance.

Linovia Linovia · Accepted Answer · 2017-05-03T00:21:30

1) Is pk / a lookup field argument required in a detail_route?

Yes. Thanks for spotting it, it's fixed in the repository and will be updated next time the documentation will be generated.

2) If not, then how does self.get_object() know which object to get?

The view's arguments / keyword arguments is stored in the view.args and view.kwargs which get_object uses.

3) Also, if not, then shouldn't @list_route be used instead since a lookup is not even being used?

It's been used through self.get_object which returns the associated users so it's a detail_route.

Is a lookup field required in a routers `detail_route`?

1 Answers