Serializer + object hook for Decimal and date objects

decimal_date_json_handlers.py

from json import loads, dumps, JSONEncoder
from decimal import Decimal
import datetime

class Encoder(JSONEncoder):

    def default(self, obj):
        if isinstance(obj, Decimal):
            return '__decimal__' + str(obj)

        if isinstance(obj, datetime.date):
            return '__date__' + obj.strftime('%Y-%m-%d')

        return JSONEncoder.default(self, obj)


def object_hook(dict_):
    for key, val in dict_.items():
        if val.startswith('__decimal__'):
            val = Decimal(val.replace('__decimal__', ''))
            dict_[key] = val

        elif val.startswith('__date__'):
            val = val.replace('__date__', '')
            val = datetime.datetime.strptime(val, '%Y-%m-%d').date()
            dict_[key] = val

    return dict_

if __name__=='__main__':

    obj = {'d': Decimal('1.345457568'), 'dt': datetime.date.today()}
    obj_ser = dumps(obj, cls=Encoder)
    obj2 = loads(obj_ser, object_hook=object_hook)
    print obj==obj2
    print obj_ser