Fixing invalid JSON escape

问题:

KISSmetrics generates invalid JSON strings I need to parse. I'm getting tons of errors like

ERROR 2013-03-04 04:31:12,253 Invalid \escape: line 1 column 132 (char 132): {"search engine":"Google","_n":"search engine hit","_p":"z392cpdpnm6silblq5mac8kiugq=","search terms":"happy new year animation 1920\303\2271080 hd","_t":1356390128}

ERROR 2013-03-04 04:34:19,153 Invalid \escape: line 1 column 101 (char 101): {"search engine":"Google","_n":"ad campaign hit","_p":"byskpczsw6sorbmzqi0tk1uimgw=","search terms":"\331\203\330\261\330\252\331\207 \331\201\331\212\330\257\331\212\330\244\331\211 \330\256\331\212\331\204\330\247\330\255\331\211 \331\203\331\210\330\261\330\257\331\211","_t":1356483052}

My code is:

for line in lines:
    try:
        data = self.clean_data(json.loads(line))
        except ValueError, e:
            logger.error('%s: %s' % (e.message, line))

Example raw data:

{"search engine":"Google","_n":"search engine hit","_p":"kvceh84hzbhywcnlivv+hdztizw=","search terms":"military sound effects programs","_t":1356034177}

Is there any chance to cleanup this messy JSON and parse it? Thanks for your help.

回答1:

Your input data contains octal escapes; those would be invalid indeed. Replace them with decoded bytes using a regular expression:

import re

invalid_escape = re.compile(r'\\[0-7]{1,3}')  # up to 3 digits for byte values up to FF

def replace_with_byte(match):
    return chr(int(match.group(0)[1:], 8))

def repair(brokenjson):
    return invalid_escape.sub(replace_with_byte, brokenjson)

This makes your input work:

>>> data1 = r"""{"search engine":"Google","_n":"search engine hit","_p":"z392cpdpnm6silblq5mac8kiugq=","search terms":"happy new year animation 1920\303\2271080 hd","_t":1356390128}"""
>>> json.loads(repair(data1))
{u'_n': u'search engine hit', u'search terms': u'happy new year animation 1920\xd71080 hd', u'_p': u'z392cpdpnm6silblq5mac8kiugq=', u'_t': 1356390128, u'search engine': u'Google'}
>>> print json.loads(repair(data1))['search terms']
happy new year animation 1920×1080 hd
>>> data2 = r"""{"search engine":"Google","_n":"ad campaign hit","_p":"byskpczsw6sorbmzqi0tk1uimgw=","search terms":"\331\203\330\261\330\252\331\207 \331\201\331\212\330\257\331\212\330\244\331\211 \330\256\331\212\331\204\330\247\330\255\331\211 \331\203\331\210\330\261\330\257\331\211","_t":1356483052}"""
>>> json.loads(repair(data2)){u'_n': u'ad campaign hit', u'search terms': u'\u0643\u0631\u062a\u0647 \u0641\u064a\u062f\u064a\u0624\u0649 \u062e\u064a\u0644\u0627\u062d\u0649 \u0643\u0648\u0631\u062f\u0649', u'_p': u'byskpczsw6sorbmzqi0tk1uimgw=', u'_t': 1356483052, u'search engine': u'Google'}
>>> print json.loads(repair(data2))['search terms']
كرته فيديؤى خيلاحى كوردى

回答2:

Consider cjson for this exact scenario (https://pypi.python.org/pypi/python-cjson)

Seems to handle the escaped octals (and quick).

回答3:

I had similar problem and just replacing json library with yaml solved the issue. (YAML is compatible with JSON.)

Example:

import yaml

obj = yaml.load(json_string) # instead of json.loads(json_string)