DRF nested router serializer source fields from url

Question

I have an author and books model. An author has many books with him

class Author(Model):
    id = UUIDField(primary_key=True, default=uuid4, editable=False)
    name = CharField(max_length=50)
    email = CharField(max_length=50)

class Book(Model):
    id = UUIDField(primary_key=True, default=uuid4, editable=False)
    name = CharField(max_length=50)
    author = ForeignKey(Author, on_delete=models.CASCADE)

In my urls.py

author_router = SimpleRouter()
author_router.register(
    r"author", AuthorViewSet, basename=author
)

nested_author_router = NestedSimpleRouter(author_router, r"author", lookup="author")
nested_author_router.register(r"book", BookViewSet)

In my searlizers.py

class BookSerializer(ModelSerializer):
    class Meta:
        model = Book
        fields = (
            "id",
            "name",
            "author",
        )
        extra_kwargs = {
            "id": {"required": False},
            "author": {"required": False},
        }

class AuthorSerialzer(ModelSerializer):
        class Meta:
            model = Author
            fields = (
                "id",
                "name",
                "email",
            )
            extra_kwargs = {
                "id": {"required": False},
            }

In views.py

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


    def create(self, request, author_pk):
        data = request.data
        data["author"] = author_pk
        serializer = self.get_serializer(data=data)
        serializer.is_valid(raise_exception=True)
        serializer.save() 
        return Response(serializer.data)

Since books are related to the author and I am using nested routers the curl call would look like

curl --location --request POST 'localhost:8000/author/1/book' --data '{"name": "Book Name"}'

In my BookViewSet I end up manually adding the author_pk to the data object before calling serializer is_valid method. Is there a way to specify the source from URL route or any better way of doing this?

Answer 1

In this case you can pass the author_pk to save() to automatically set the author id of the newly created book, as explained here:

    def create(self, request, author_pk):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        serializer.save(author_id=author_pk) 
        return Response(serializer.data)