Handling Circular References in JSON Serialization with Python's JSON Module
I've been struggling with this for a few days now and could really use some help. I'm trying to serialize a Python object that contains circular references into JSON using the built-in `json` module, but I'm running into a `ValueError`. The object I'm working with is a tree structure where each node contains a reference to its parent. Here’s a simplified version of my class: ```python class Node: def __init__(self, value, parent=None): self.value = value self.parent = parent self.children = [] def add_child(self, child): child.parent = self self.children.append(child) root = Node('root') child1 = Node('child1') child2 = Node('child2') root.add_child(child1) root.add_child(child2) child1.add_child(Node('child1.1')) child2.add_child(Node('child2.1')) # This creates a circular reference child1.parent = root # This line is redundant and just for illustration ``` When I try to serialize `root` using `json.dumps(root)`, I get the following behavior: ``` ValueError: Circular reference detected ``` I attempted to resolve this using a custom encoder by subclassing `json.JSONEncoder` and overriding the `default` method, but I’m not sure how to handle the circular references properly. Here’s what I tried: ```python import json class NodeEncoder(json.JSONEncoder): def default(self, obj): if isinstance(obj, Node): return { 'value': obj.value, 'children': obj.children # This causes circular reference issues } return json.JSONEncoder.default(self, obj) ``` However, that still leads to the same circular reference scenario. What’s the best approach to serialize this kind of structure without running into circular reference problems? Any suggestions or best practices would be greatly appreciated! For context: I'm using Python on macOS. I'd really appreciate any guidance on this. For reference, this is a production microservice. How would you solve this?