Django Rest API – Router – View Class – Part3

In this blog post we will see more details on View Class and also router.

Router

Read this https://www.django-rest-framework.org/api-guide/routers/ to understand routers briefly.

In our previous blog post we saw simple routes with regex. DRF router can be used that as well with simple regex and its quite power. Here are few blogs which show different useful regex and many can be found online as well

https://simpleisbetterthancomplex.com/references/2016/10/10/url-patterns.html

Let’s take the first route shown in above blog as an example in our code base

 url(r'^(?P<pk>\d+)/$', views.index, name='test_regex'),

and our function would look like

@api_view()
def index(request, pk):
    todo = Todo.objects.get(pk=pk)
    ser = TodoSerializer(todo)
    return Response(ser.data) 

Take note how we are passing ‘pk’ dynamic variable from route to function. This is quite simple and can be extended as required

Simple RouteR and View Sets

DRF has a concept of “simple router”. This is to be used with ViewSets only and mainly reason for this it generate lot of routes automatically based on the ViewSets.

Before going into detail let’s recap what we have seen till now because this can be a bit confusing

a) @api_view: this is simple function based view and can be paired with regex based routing. By default it’s GET type but we can add more types easily. This suppose decorators for permission, authentication, etc etc https://www.django-rest-framework.org/api-guide/views/#function-based-views

b) ViewClass (APIView): this is a class based view with methods for “get”, “post” “list” “delete” etc. This can be paired with regex based routing and also suppose decorates for auth, permission etc https://www.django-rest-framework.org/api-guide/views/#class-based-views

c) Generic Views : this is extension of APIView and provides default features on top of it.

The above view method’s are quite flexible and can be easily paired with routes using regex.

Pros: Easy to use and implement. Easy to understand

Cons: No fixed structure, this will cause problem in large projects as every developer will make things on this own. No code consistency will be there.

View Sets

View sets are similar to Generic Views, except that are paired with “SimpleRouter” and hence provide a consistent interface for routing and code structure.

https://www.django-rest-framework.org/api-guide/viewsets/

Let’s see how this works

There are all the different actions a viewset provides by default

 def list(self, request):
        pass

    def create(self, request):
        pass

    def retrieve(self, request, pk=None):
        pass

    def update(self, request, pk=None):
        pass

    def partial_update(self, request, pk=None):
        pass

    def destroy(self, request, pk=None):
        pass

Let’s see this at code level

//todo/views.py

from todo.models import Todo
from todo.serializers import TodoSerializer

from rest_framework import viewsets


class TodoViewSet(viewsets.ModelViewSet):
    serializer_class = TodoSerializer
    queryset = Todo.objects.all()

//todo/urls.py

from rest_framework.routers import DefaultRouter
from todo.views import TodoViewSet


router = DefaultRouter()

router.register(r'todo', TodoViewSet, basename='todo')

urlpatterns = router.urls

We are using “ModelViewSet” because this implement all functions i.e create, delete, list, etc by default. If you use instead “ViewSet” it won’t have any of the functions implemented.

To see this open postman and fire all the route GET, POST, PUT, etc and all will work

So basically with just a few lines of code we are able to setup full CRUD operations

Read in detail simple router and default router to understand there difference between them and what kind of routes they generate automatically

https://www.django-rest-framework.org/api-guide/routers/#simplerouter

https://www.django-rest-framework.org/api-guide/routers/#defaultrouter

ViewSets Actions

Actions are also quite important in viewset. Basically suppose we want to add an extra function to viewset which is out of the standard CRUD. It done via action.

Read more about actions here the explanation is quite clear how to use it https://www.django-rest-framework.org/api-guide/viewsets/#marking-extra-actions-for-routing

Read about different view sets here as well https://www.django-rest-framework.org/api-guide/viewsets/#api-reference