ViewSets and Routers

from rest_framework import viewsets
from .models import Book
from .serializers import BookSerializer

class BookViewSet(viewsets.ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

from django.urls import path, include
from rest_framework.routers import DefaultRouter
from .views import BookViewSet

router = DefaultRouter()
router.register('books', BookViewSet, basename='book')

urlpatterns = [
    path('api/', include(router.urls)),
]

GET    /api/books/       -> list all books
POST   /api/books/       -> create a book
GET    /api/books/1/     -> retrieve book with id 1
PUT    /api/books/1/     -> update book with id 1
DELETE /api/books/1/     -> delete book with id 1

1. Writing separate URL patterns by hand for a ModelViewSet instead of registering it with a router, duplicating work the router already does.
2. Confusing ViewSet with View — a ViewSet doesn't map directly to one URL, it maps to a set of related URLs generated by a router.
3. Forgetting to include the router's generated urls (router.urls) in the project's URL configuration.

• ModelViewSet provides list, retrieve, create, update, and destroy actions from a single class.
• DefaultRouter automatically generates the URL patterns for a registered ViewSet, including a browsable API root.
• Registering a ViewSet with a router replaces writing each URL pattern by hand.