Facebook JSON badly encoded

问题

I downloaded my Facebook messenger data (in your Facebook account, go to settings, then to Your Facebook information, then Download your information, then create a file with at least the Messages box checked) to do some cool statistics

However there is a small problem with encoding. I'm not sure, but it looks like Facebook used bad encoding for this data. When I open it with text editor I see something like this: Rados\u00c5\u0082aw. When I try to open it with python (UTF-8) I get RadosÅ\x82aw. However I should get: Radosław.

My python script:

text = open(os.path.join(subdir, file), encoding='utf-8')
conversations.append(json.load(text))

I tried a few most common encodings. Example data is:

{
  "sender_name": "Rados\u00c5\u0082aw",
  "timestamp": 1524558089,
  "content": "No to trzeba ostatnie treningi zrobi\u00c4\u0087 xD",
  "type": "Generic"
}

回答1:

I can indeed confirm that the Facebook download data is incorrectly encoded; a Mojibake. The original data is UTF-8 encoded but was decoded as Latin -1 instead. I’ll make sure to file a bug report.

In the meantime, you can repair the damage in two ways:

Decode the data as JSON, then re-encode any strings as Latin-1, decode again as UTF-8:

>>> import json
>>> data = r'"Rados\u00c5\u0082aw"'
>>> json.loads(data).encode('latin1').decode('utf8')
'Radosław'

Load the data as binary, replace all \u00hh sequences with the byte the last two hex digits represent, decode as UTF-8 and then decode as JSON:

import re
from functools import partial

fix_mojibake_escapes = partial(
     re.compile(rb'\\u00([\da-f]{2})').sub,
     lambda m: bytes.fromhex(m.group(1).decode()))

with open(os.path.join(subdir, file), 'rb') as binary_data:
    repaired = fix_mojibake_escapes(binary_data.read())
data = json.loads(repaired.decode('utf8'))

From your sample data this produces:

{'content': 'No to trzeba ostatnie treningi zrobić xD',
 'sender_name': 'Radosław',
 'timestamp': 1524558089,
 'type': 'Generic'}

回答2:

My solution for parsing objects use parse_hook callback on load/loads function:

import json


def parse_obj(dct):
    for key in dct:
        dct[key] = dct[key].encode('latin_1').decode('utf-8')
        pass
    return dct


data = '{"msg": "Ahoj sv\u00c4\u009bte"}'

# String
json.loads(data)  
# Out: {'msg': 'Ahoj svÄ\x9bte'}
json.loads(data, object_hook=parse_obj)  
# Out: {'msg': 'Ahoj světe'}

# File
with open('/path/to/file.json') as f:
     json.load(f, object_hook=parse_obj)
     # Out: {'msg': 'Ahoj světe'}
     pass

Update:

Solution for parsing list with strings does not working. So here is updated solution:

import json


def parse_obj(obj):
    for key in obj:
        if isinstance(obj[key], str):
            obj[key] = obj[key].encode('latin_1').decode('utf-8')
        elif isinstance(obj[key], list):
            obj[key] = list(map(lambda x: x if type(x) != str else x.encode('latin_1').decode('utf-8'), obj[key]))
        pass
    return obj

回答3:

Based on @Martijn Pieters solution, I wrote something similar in Java.

public String getMessengerJson(Path path) throws IOException {
    String badlyEncoded = Files.readString(path, StandardCharsets.UTF_8);
    String unescaped = unescapeMessenger(badlyEncoded);
    byte[] bytes = unescaped.getBytes(StandardCharsets.ISO_8859_1);
    String fixed = new String(bytes, StandardCharsets.UTF_8);
    return fixed;
}

The unescape method is inspired by the org.apache.commons.lang.StringEscapeUtils.

private String unescapeMessenger(String str) {
    if (str == null) {
        return null;
    }
    try {
        StringWriter writer = new StringWriter(str.length());
        unescapeMessenger(writer, str);
        return writer.toString();
    } catch (IOException ioe) {
        // this should never ever happen while writing to a StringWriter
        throw new UnhandledException(ioe);
    }
}

private void unescapeMessenger(Writer out, String str) throws IOException {
    if (out == null) {
        throw new IllegalArgumentException("The Writer must not be null");
    }
    if (str == null) {
        return;
    }
    int sz = str.length();
    StrBuilder unicode = new StrBuilder(4);
    boolean hadSlash = false;
    boolean inUnicode = false;
    for (int i = 0; i < sz; i++) {
        char ch = str.charAt(i);
        if (inUnicode) {
            unicode.append(ch);
            if (unicode.length() == 4) {
                // unicode now contains the four hex digits
                // which represents our unicode character
                try {
                    int value = Integer.parseInt(unicode.toString(), 16);
                    out.write((char) value);
                    unicode.setLength(0);
                    inUnicode = false;
                    hadSlash = false;
                } catch (NumberFormatException nfe) {
                    throw new NestableRuntimeException("Unable to parse unicode value: " + unicode, nfe);
                }
            }
            continue;
        }
        if (hadSlash) {
            hadSlash = false;
            if (ch == 'u') {
                inUnicode = true;
            } else {
                out.write("\\");
                out.write(ch);
            }
            continue;
        } else if (ch == '\\') {
            hadSlash = true;
            continue;
        }
        out.write(ch);
    }
    if (hadSlash) {
        // then we're in the weird case of a \ at the end of the
        // string, let's output it anyway.
        out.write('\\');
    }
}

来源：https://stackoverflow.com/questions/50008296/facebook-json-badly-encoded

标签

python

python-3.x

unicode

mojibake