todict_mixin.py

#!/usr/local/bin/python3
# -*- coding: utf-8 -*-


from datetime import datetime


class DictMixin(object):
    def to_dict(self):
        return self._parse_dict(self.__dict__)

    def _parse_dict(self, instance_dict):
        result = {}
        for key, value in instance_dict.items():
            result[key] = self._parse(value)
        return result

    def _parse(self, value):
        if isinstance(value, DictMixin):
            return value.to_dict()
        elif isinstance(value, dict):
            return self._parse_dict(value)
        elif isinstance(value, list):
            return [self._parse(v) for v in value]
        elif hasattr(value, '__dict__'):
            return self._parse_dict(value.__dict__)
        elif isinstance(value, datetime):
            return datetime.isoformat(value)
        else:
            return value


class Person():
    def __init__(self, name, age):
        self.name, self.age = name, age
        self.created_at = datetime.utcnow()


class Programmer(DictMixin):
    def __init__(self, person, role):
        self.person = person
        self.role = role


if __name__ == '__main__':
    p = Person('Kiran', 25)
    pr = Programmer(p, 'Web Developer')
    print(pr.to_dict())

# Output:
# {
#    'person': {
#        'created_at': '2015-10-20T08:34:57.193786', 
#        'age': 25, 
#        'name': 'Kiran'
#    }, 
#    'role': 'Web Developer'
# }