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addChecksum.py
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addChecksum.py
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#!/usr/bin/env python
# coding: utf-8
# The contents of this file are subject to the Mozilla Public License
# Version 1.1 (the "License"); you may not use this file except in
# compliance with the License. You may obtain a copy of the License at
# http://www.mozilla.org/MPL/
#############################################################################
# This is a reference script to add checksums to downloadable #
# subscriptions. The checksum will be validated by Adblock Plus on download #
# and checksum mismatches (broken downloads) will be rejected. #
# #
# To add a checksum to a subscription file, run the script like this: #
# #
# perl addChecksum.pl < subscription.txt > subscriptionSigned.txt #
# #
# Note: your subscription file should be saved in UTF-8 encoding, otherwise #
# the operation will fail. #
# #
#############################################################################
import sys, re, codecs, hashlib, base64
checksumRegexp = re.compile(r'^\s*!\s*checksum[\s\-:]+([\w\+\/=]+).*\n', re.I | re.M)
def addChecksum(data):
checksum = calculateChecksum(data)
data = re.sub(checksumRegexp, '', data)
data = re.sub(r'(\r?\n)', r'\1! Checksum: %s\1' % checksum, data, 1)
return data
def calculateChecksum(data):
md5 = hashlib.md5()
md5.update(normalize(data).encode('utf-8'))
return base64.b64encode(md5.digest()).rstrip('=')
def normalize(data):
data = re.sub(r'\r', '', data)
data = re.sub(r'\n+', '\n', data)
data = re.sub(checksumRegexp, '', data)
return data
def readStream(stream):
reader = codecs.getreader('utf8')(stream)
try:
return reader.read()
except Exception, e:
raise Exception('Failed reading data, most likely not encoded as UTF-8:\n%s' % e)
if __name__ == '__main__':
data = addChecksum(readStream(sys.stdin))
sys.stdout.write(data.encode('utf-8'))