Handling lazy JSON in Python - 'Expecting property name'

Question

Using Pythons (2.7) 'json' module I'm looking to process various JSON feeds. Unfortunately some of these feeds do not conform with JSON standards - in specific some keys are not wrapped in double speech-marks ("). This is causing Python to bug out.

Before writing an ugly-as-hell piece of code to parse and repair the incoming data, I thought I'd ask - is there any way to allow Python to either parse this malformed JSON or 'repair' the data so that it would be valid JSON?

Working example

import json
>>> json.loads('{"key1":1,"key2":2,"key3":3}')
{'key3': 3, 'key2': 2, 'key1': 1}

Broken example

import json
>>> json.loads('{key1:1,key2:2,key3:3}')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python27\lib\json\__init__.py", line 310, in loads
    return _default_decoder.decode(s)
  File "C:\Python27\lib\json\decoder.py", line 346, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "C:\Python27\lib\json\decoder.py", line 362, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Expecting property name: line 1 column 1 (char 1)

I've written a small REGEX to fix the JSON coming from this particular provider, but I forsee this being an issue in the future. Below is what I came up with.

>>> import re
>>> s = '{key1:1,key2:2,key3:3}'
>>> s = re.sub('([{,])([^{:\s"]*):', lambda m: '%s"%s":'%(m.group(1),m.group(2)),s)
>>> s
'{"key1":1,"key2":2,"key3":3}'

Answer 1

You're trying to use a JSON parser to parse something that isn't JSON. Your best bet is to get the creator of the feeds to fix them.

I understand that isn't always possible. You might be able to fix the data using regexes, depending on how broken it is:

j = re.sub(r"{\s*(\w)", r'{"\1', j)
j = re.sub(r",\s*(\w)", r',"\1', j)
j = re.sub(r"(\w):", r'\1":', j)