In Python, have json not escape a string -

i caching json data, , in storage represented json-encode string. no work performed on json server before sending client, other collation of multiple cached objects, this:

def get_cached_items():   item1 = cache.get(1)   item2 = cache.get(2)   return json.dumps(item1=item1, item2=item2, msg="123") 

there may other items included return value, in case represented msg="123".

the issue cached items double-escaped. behoove library allow pass-through of string without escaping it.

i have looked @ documentation json.dumps default argument, seems place 1 address this, , searched on google/so found no useful results.

it unfortunate, performance perspective, if had decode json of each cached items send browser. unfortunate complexity perspective not able use json.dumps.

my inclination write class stores cached string , when default handler encounters instance of class uses string without perform escaping. have yet figure out how achieve though, , grateful thoughts , assistance.

edit clarity, here example of proposed default technique:

class rawjson(object):    def __init__(self, str):        self.str = str  class jsonencoderwithraw(json.jsonencoder):    def default(self, o):        if isinstance(o, rawjson):            return o.str # avoid call `encode_basestring` (or ascii equiv.)        return super(jsonencoderwithraw, self).default(o) 

here degenerate example of above:

>>> class m():        str = '' >>> m = m() >>> m.str = json.dumps(dict(x=123)) >>> json.dumps(dict(a=m), default=lambda (o): o.str) '{"a": "{\\"x\\": 123}"}' 

the desired output include unescaped string m.str, being:

'{"a": {"x": 123}}' 

it if json module did not encode/escape return of default parameter, or if same avoided. in absence of method via default parameter, 1 may have achieve objective here overloading encode , iterencode method of jsonencoder, brings challenges in terms of complexity, interoperability, , performance.

a quick-n-dirty way patch json.encoder.encode_basestring*() functions:

import json  class rawjson(unicode):     pass  # patch json.encoder module name in ['encode_basestring', 'encode_basestring_ascii']:     def encode(o, _encode=getattr(json.encoder, name)):         return o if isinstance(o, rawjson) else _encode(o)     setattr(json.encoder, name, encode)   print(json.dumps([1, rawjson(u'["abc", 2]'), u'["def", 3]'])) # -> [1, ["abc", 2], "[\"def\", 3]"]