Dictionary with JSON-serialized internal buffer. Placed in the Public Domain.

JsonSerializedDict

from json import dumps, loads
from UserDict import DictMixin

class JsonSerializedDict(DictMixin):
    """

    >>> JSD = JsonSerializedDict
    >>> d = JSD()
    >>> print d
    {}
    >>> d['asdf'] = 42
    >>> print d.json
    {"asdf": 42}
    >>> print d.items()
    [(u'asdf', 42)]
    >>> print 'asdf' in d
    True
    >>> d.pop('asdf')
    42
    >>> d.get('abc', 'def')
    'def'
    """

    def __init__(self, json='{}'):
        loads(json) # assert if it's valid json
        self.json = json

    @property
    def as_dict(self):
        return loads(self.json)

    def __getitem__(self, key):
        return self.as_dict[key]

    def __setitem__(self, key, value):
        d = self.as_dict
        d[key] = value
        self.json = dumps(d)

    def __delitem__(self, key):
        d = self.as_dict
        del d[key]
        self.json = dumps(d)

    def keys(self):
        return self.as_dict.keys()

if __name__=='__main__':
    from doctest import testmod
    testmod()