Serialize python objet to Json

json_serialize.py

# coding: utf-8

import json


class UserEncoder(json.JSONEncoder):

    def default(self, obj):
        return obj.__dict__


class User(object):

    def __init__(self, username, password):
        self.username = username
        self.password = password


david = User("David", "password")

#Serializamos el objeto, el parametro cls corresponde al encoder que queramos usar
#En nuestro caso UserEncoder
serialize = json.dumps(david, cls=UserEncoder, indent=4)

#un print rápidito
print serialize