jsondatetime.py

import json
import datetime

class DateTimeDecoder(json.JSONDecoder):
    def __init__(self, *args, **kargs):
        json.JSONDecoder.__init__(
            self,
            object_hook=self.dict_to_object,
            *args,
            **kargs
        )

    def dict_to_object(self, d): 
        if '__type__' not in d:
            return d
        type = d.pop('__type__')
        types = {
            'datetime': datetime.datetime
        }
        try:
            return types[type](**d)
        except TypeError:
            d['__type__'] = type
            return d

class DateTimeEncoder(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, datetime.datetime):
            return {
                '__type__': 'datetime',
                'year': obj.year,
                'month': obj.month,
                'day': obj.day,
                'hour': obj.hour,
                'minute': obj.minute,
                'second': obj.second,
                'microsecond': obj.microsecond,
            }   
        else:
            return json.JSONEncoder.default(self, obj)

#use like:           
json.loads(some_string, cls=DateTimeDecoder)
json.dumps(some_dict, cls=DateTimeEncoder)
# load and dump variants work the same, just provide the cls argument