python - Unbaking mojibake

Question

When you have incorrectly decoded characters, how can you identify likely candidates for the original string?

?×èè????è¤?_üiaAajaüapaXüj_10òb.png

I know for a fact that this image filename should have been some Japanese characters. But with various guesses at urllib quoting/unquoting, encode and decode iso8859-1, utf8, I haven't been able to unmunge and get the original filename.

Is the corruption reversible?

Answer 1

You could use chardet (install with pip):

import chardet

your_str = "?×èè????è¤?_üiaAajaüapaXüj_10òb"
detected_encoding = chardet.detect(your_str)["encoding"]

try:
    correct_str = your_str.decode(detected_encoding)
except UnicodeDecodeError:
    print("Could not estimate encoding")

Result: 時間試験観点（アニメパス）_10秒 (no idea if this could be correct or not)

For Python 3 (source file encoded as utf8):

import chardet
import codecs

falsely_decoded_str = "?×èè???|è¤?_üiaAajaüapaXüj_10òb"

try:
    encoded_str = falsely_decoded_str.encode("cp850")
except UnicodeEncodeError:
    print("could not encode falsely decoded string")
    encoded_str = None

if encoded_str:
    detected_encoding = chardet.detect(encoded_str)["encoding"]

    try:
        correct_str = encoded_str.decode(detected_encoding)
    except UnicodeEncodeError:
        print("could not decode encoded_str as %s" % detected_encoding)

    with codecs.open("output.txt", "w", "utf-8-sig") as out:
        out.write(correct_str)

In summary:

>>> s = '?×èè????è¤?_üiaAajaüapaXüj_10òb.png'
>>> s.encode('cp850').decode('shift-jis')
'時間試験観点（アニメパス）_10秒.png'