Flask-RESTful: How to properly handle nested resource serialization for complex relationships?
After trying multiple solutions online, I still can't figure this out... I'm getting frustrated with I'm following best practices but I'm maintaining legacy code that After trying multiple solutions online, I still can't figure this out......... I'm currently working on a Flask application using Flask-RESTful to build a REST API, and I'm running into issues with serializing nested resources. My app has a `User` model that has a one-to-many relationship with a `Post` model. I need to return a user along with all their posts when accessing the `/users/<id>` endpoint, but I'm not sure how to properly serialize the nested `Post` objects within the `User` response. Here's the relevant code for my models: ```python from flask_sqlalchemy import SQLAlchemy db = SQLAlchemy() class User(db.Model): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(80), unique=True, nullable=False) posts = db.relationship('Post', backref='author', lazy=True) class Post(db.Model): id = db.Column(db.Integer, primary_key=True) title = db.Column(db.String(120), nullable=False) content = db.Column(db.Text, nullable=False) user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False) ``` And here's how I currently have my resource set up: ```python from flask_restful import Resource, marshal_with, fields user_fields = { 'id': fields.Integer, 'username': fields.String, 'posts': fields.List(fields.String), # This is where I struggle } class UserResource(Resource): @marshal_with(user_fields) def get(self, id): user = User.query.get(id) # Need to serialize user posts here return user ``` The issue I'm facing is that when I try to include the posts directly in the `user_fields`, I get only the post IDs instead of their details. I tried modifying the `posts` field to use a nested field definition, but it seems overly complicated. After some research, I found that using a custom method to serialize the `posts` could help, but I haven't figured out how to integrate that cleanly into the current structure. Any suggestions on how to effectively serialize the nested `Post` objects so that the API returns the full details of each post related to the user? Iām using Flask 2.0 and Flask-RESTful 0.3.9. Thanks in advance! Any help would be greatly appreciated! I'd be grateful for any help. For context: I'm using Python on CentOS. Am I missing something obvious? This issue appeared after updating to Python LTS. I'd be grateful for any help. I recently upgraded to Python 3.10. I appreciate any insights! I'm working with Python in a Docker container on Linux.