Decode input passed to PowerShell's FromBase64String function

decode-posh-base64string.py

#!/usr/bin/env python

import gzip
import base64
import StringIO
import sys


def gunzip(raw_data):
    decoded_data_obj = StringIO.StringIO(raw_data)
    decompressed_data_obj = gzip.GzipFile(fileobj=decoded_data_obj)

    return decompressed_data_obj.read()


if __name__ == '__main__':

    raw_data = sys.argv[1]

    try:
        print gunzip(base64.b64decode(raw_data))
    except IOError, err:
        if 'Not a gzipped file' in str(err):
            print base64.b64decode(raw_data)
    except TypeError, err:
        if 'Incorrect padding' in str(err):
            pad_delta = len(raw_data) % 4
            if pad_delta == 0:
                print 'O NOES: A new edge case!'
            else:
                raw_data += '0' * pad_delta
                print base64.b64decode(raw_data)