Django 4.2: Issues with Nested Serializers and Validation in DRF for Complex Models
I'm experimenting with I'm getting frustrated with I tried several approaches but none seem to work. I'm working on a Django 4.2 application using Django Rest Framework (DRF) and I've run into an issue with nested serializers. I have a `Book` model that has a foreign key relationship with an `Author` model, and I want to create or update a book along with its author in a single API call. Here’s a simplified version of my models: ```python class Author(models.Model): name = models.CharField(max_length=100) class Book(models.Model): title = models.CharField(max_length=200) author = models.ForeignKey(Author, related_name='books', on_delete=models.CASCADE) ``` I've defined my serializers like this: ```python from rest_framework import serializers class AuthorSerializer(serializers.ModelSerializer): class Meta: model = Author fields = ['id', 'name'] class BookSerializer(serializers.ModelSerializer): author = AuthorSerializer() class Meta: model = Book fields = ['id', 'title', 'author'] def create(self, validated_data): author_data = validated_data.pop('author') author, created = Author.objects.get_or_create(**author_data) book = Book.objects.create(author=author, **validated_data) return book ``` When I try to create a new book with the following payload: ```json { "title": "New Book", "author": { "name": "John Doe" } } ``` I get the following error message: ``` TypeError: get_or_create() argument after ** must be a mapping, not AuthorSerializer ``` I've tried using `is_valid()` on the `BookSerializer` before creating the `Book` instance, but it seems like the nested `AuthorSerializer` is causing issues. I suspect it might be related to how I'm unpacking the `author_data`. Additionally, I want to ensure that if the author already exists, I can update their details instead of creating a new record. What’s the best way to handle nested serializers like this in DRF while making sure that the author details can be updated if they already exist? Also, how can I improve error handling for cases where the author data might be incomplete or invalid? Any help would be greatly appreciated! Any help would be greatly appreciated! Is there a better approach? I'd really appreciate any guidance on this.