json_dunder

Encdoe objects with a __json__ dunder method and decode objects with a __from_json__ dunder method.

import json_dunder

# Use tells json to use this class
coder = json_dunder.JsonDunderTypeCoder().use()

@coder.register
class A:
    def __init__(self, x):
        self.x = x

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return self.x == other.x
        return False

    def __json__(self):
        return {"x": self.x}

    @classmethod
    def __from_json__(cls, d: dict):
        return cls(**d)

@coder.register
class B:
    def __init__(self, a, y):
        self.a = a
        self.y = y

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return self.a == other.a and self.y == other.y
        return False

    def __json__(self):
        return {"a": self.a, "y": self.y}

    @classmethod
    def __from_json__(cls, d: dict):
        return cls(**d)

a = A(1)
b = B(a, 2)

sa = json_dunder.dumps(a)
assert sa == '{"x": 1, "__json_type__": "__main__.A"}'

sb = json_dunder.dumps(b)
assert sb == '{"a": {"x": 1, "__json_type__": "__main__.A"}, "y": 2, "__json_type__": "__main__.B"}'

obj = json_dunder.loads(sa)
assert obj == a

obj = json_dunder.loads(sb)
assert obj.a == a
assert obj == b

pip install json_dunder