How to change json encoding behaviour for serializable python object?

Question

It is easy to change the format of an object which is not JSON serializable eg datetime.datetime.

My requirement, for debugging purposes, is to alter the way some cu

Answer 1

Why can't you just create a new object type to pass to the encoder? Try:

class MStuff(object):
    def __init__(self, content):
        self.content = content

class mDict(MStuff):
    pass

class mList(MStuff):
    pass

def json_debug_handler(obj):
    print("object received:")
    print(type(obj))
    print("\n\n")
    if  isinstance(obj, datetime.datetime):
        return obj.isoformat()
    elif isinstance(obj,MStuff):
        attrs = {}
        for key in obj.__dict__:
            if not ( key.startswith("_") or key == "content"):
                attrs[key] = obj.__dict__[key]

        return {'orig':obj.content , 'attrs': attrs}
    else:
        return None

You could add validation on the mDict and mList if desired.