How to build a Django REST route that extracts multiple arguments from the URL?

Question

I have built some Django-Rest-Framework APIs to my application. These APIs do things like return lists of Model Instances and return counts of how many models meet a pre-determined criteria.

Here is what the my ViewSet looks like:

class MyObjectsViewSet(viewsets.ViewSet):

    def retrieve(self,request,pk=None):
        queryset = ## Do something here to return a list of myObjects
        serializer = MyObjectsSerializer(queryset) ## MyObjectsSerializer not shown here.
        return Response(serializer.data,status=status.HTTP_200_OK)

And here is what my urls.py looks like for this endpoint:

router = routers.DefaultRouter()
router.register(r'myObjects', views.myObjectsViewSet, base_name="myObjects")

urlpatterns = patterns('',
    ...
    url(r'^api/', include(router.urls)),
    ...
)

The above code allows me to take a single parameter to the API and use it as the pk argument in MyObjectsViewSet.retrieve(). So when I point my browser to /api/MyObjects/60/, retrieve() is called with pk == 60. Great. Everything is awesome.

But now I need an API that will do something more. I need an API that takes two numeric parameters ("pk" and "otherArg") and calls another viewSet (MyObjectsNewView) with those two arguments. So that when I point my browser to /api/MyObjects/60/59/, MyObjectsNewView.retrieve() will be called with arguments pk == 60 and otherArg == 59.

How can I design my routes in url.py and my Viewsets to make this work?

In other cases, when I was designing non-REST urls, I used regexps and used notation like this to specify extract arguments from a URL string: (?P<MyObjectID>\d+).

It would seem like I should be able to do the same type of thing here. However, it automatically takes in the pk argument without me specifying it anywhere in the route, so now I'm confused how to add another argument to this route when the first pk argument sorta appeared magically without any regexp pattern.

Answer 1

Without using regex drf provides path with type prefix, if you don't have strict validation for "pk" and "otherArg". So,

Step 1: In urlpatters,

path('/api/<int:id>/<otherArg>/', YourViewset.action_name, name="action_name")

Step 2: In Viewset

@action(methods=['get'],detail=True/False)

Step 3: Below @action

def action_name(self, id, otherArg):

Now use id, otherArg/s in function. Make changes and use.

Answer 2

Write a custom detail route and change the signature to pass in the additional kwarg you intend to use. Then, customize the url path.

from rest_framework.decorators import detail_route
from rest_framework import viewsets

class MyObjectsViewSet(viewsets.ViewSet):

    @detail_route(methods=['get'], url_path='(?P<oid>\d+)')
    def get_with_objectid(self,request,pk=None, oid=None):
        queryset = ## Do something here with oid to return a list of myObjects
        serializer = MyObjectsSerializer(queryset) ## MyObjectsSerializer not shown here.
        return Response(serializer.data,status=status.HTTP_200_OK)

Now your viewset will work with /api/MyObjects/60/59/ where pk=60 and oid=59. If the url_path was instead url_path='/thisthing/(?P(<oid>\d+)' then the viewset would register /api/MyObjects/60/thisthing/59.