How to convert a DictProxy object into JSON serializable dict?

Question

I have a DictProxy object created using multiprocessing.Manager().dict() to support concurrency. At the end of the run, I need to serialize the dict to JSON. But it's unclear how to convert the DictProxy to serializable dict object. When I tried it, I got:

TypeError: <DictProxy object, typeid 'dict' at 0x10a240ed0> is not JSON serializable

How can I fix this?

Answer 1

Late answer, but I solved the following errors:

TypeError: Object of type 'DictProxy' is not JSON serializable
TypeError: Object of type 'ListProxy' is not JSON serializable

using:

from multiprocessing import Manager

manager = Manager()

# For Dicts
x = manager.dict()
json.dumps(dict(x))

# For Lists
x = manager.list()
json.dumps(list(x))

Answer 2

Use dict_proxy._getvalue() to fetch the actual dict instance underlying the proxy, and pass that to json.dump (or whatever method you're using).

>>> import multiprocessing
>>> m = multiprocessing.Manager()
>>> d = m.dict()
>>> import json
>>> json.dumps(d)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.6/json/__init__.py", line 230, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib64/python2.6/json/encoder.py", line 367, in encode
    chunks = list(self.iterencode(o))
  File "/usr/lib64/python2.6/json/encoder.py", line 317, in _iterencode
    for chunk in self._iterencode_default(o, markers):
  File "/usr/lib64/python2.6/json/encoder.py", line 323, in _iterencode_default
    newobj = self.default(o)
  File "/usr/lib64/python2.6/json/encoder.py", line 344, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <DictProxy object, typeid 'dict' at 0x97eed0> is not JSON serializable
>>> json.dumps(d._getvalue())
'{}'