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https://gerrit.wikimedia.org/r/mediawiki/extensions/ConfirmEdit
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398 lines
12 KiB
Python
398 lines
12 KiB
Python
#!/usr/bin/python3
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#
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# Script to generate distorted text images for a captcha system.
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#
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# Copyright (C) 2005 Neil Harris
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License along
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# with this program; if not, write to the Free Software Foundation, Inc.,
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# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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# http://www.gnu.org/copyleft/gpl.html
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#
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# Further tweaks by Brion Vibber <brion@pobox.com>:
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# 2006-01-26: Add command-line options for the various parameters
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# 2007-02-19: Add --dirs param for hash subdirectory splits
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# Tweaks by Greg Sabino Mullane <greg@turnstep.com>:
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# 2008-01-06: Add regex check to skip words containing other than a-z
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import random
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import math
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import hashlib
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from optparse import OptionParser
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import os
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import sys
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import re
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import multiprocessing
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try:
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from PIL import Image
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from PIL import ImageFont
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from PIL import ImageDraw
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from PIL import ImageEnhance
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from PIL import ImageOps
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except ImportError:
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sys.exit(
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"This script requires the Python Imaging Library - http://www.pythonware.com/products/pil/"
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)
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# regex to test for suitability of words
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nonalpha = re.compile("[^a-z]")
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# Pillow 9.2 added getbbox to replace getsize, and getsize() was removed in Pillow 10
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# https://pillow.readthedocs.io/en/stable/releasenotes/10.0.0.html#font-size-and-offset-methods
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# We don't have a requirements.txt, and therefore don't declare any specific supported or min version...
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IMAGEFONT_HAS_GETBBOX = hasattr(ImageFont.ImageFont, "getbbox")
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# Does X-axis wobbly copy, sandwiched between two rotates
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def wobbly_copy(src, wob, col, scale, ang):
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x, y = src.size
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f = random.uniform(4 * scale, 5 * scale)
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p = random.uniform(0, math.pi * 2)
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rr = ang + random.uniform(-30, 30) # vary, but not too much
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int_d = Image.new("RGB", src.size, 0) # a black rectangle
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rot = src.rotate(rr, Image.BILINEAR)
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# Do a cheap bounding-box op here to try to limit work below
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bbx = rot.getbbox()
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if bbx is None:
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return src
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else:
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l, t, r, b = bbx
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# and only do lines with content on
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for i in range(t, b + 1):
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# Drop a scan line in
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xoff = int(math.sin(p + (i * f / y)) * wob)
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xoff += int(random.uniform(-wob * 0.5, wob * 0.5))
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int_d.paste(rot.crop((0, i, x, i + 1)), (xoff, i))
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# try to stop blurring from building up
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int_d = int_d.rotate(-rr, Image.BILINEAR)
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enh = ImageEnhance.Sharpness(int_d)
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return enh.enhance(2)
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def gen_captcha(text, fontname, fontsize, file_name):
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"""Generate a captcha image"""
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# white text on a black background
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bgcolor = 0x0
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fgcolor = 0xFFFFFF
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# create a font object
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font = ImageFont.truetype(fontname, fontsize)
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# determine dimensions of the text
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if IMAGEFONT_HAS_GETBBOX:
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dim = font.getbbox(text)[2:]
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else:
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dim = font.getsize(text)
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# create a new image significantly larger that the text
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edge = max(dim[0], dim[1]) + 2 * min(dim[0], dim[1])
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im = Image.new("RGB", (edge, edge), bgcolor)
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d = ImageDraw.Draw(im)
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x, y = im.size
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# add the text to the image
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d.text((x / 2 - dim[0] / 2, y / 2 - dim[1] / 2), text, font=font, fill=fgcolor)
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k = 3
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wob = 0.20 * dim[1] / k
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rot = 45
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# Apply lots of small stirring operations, rather than a few large ones
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# in order to get some uniformity of treatment, whilst
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# maintaining randomness
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for i in range(k):
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im = wobbly_copy(im, wob, bgcolor, i * 2 + 3, rot + 0)
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im = wobbly_copy(im, wob, bgcolor, i * 2 + 1, rot + 45)
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im = wobbly_copy(im, wob, bgcolor, i * 2 + 2, rot + 90)
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rot += 30
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# now get the bounding box of the nonzero parts of the image
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bbox = im.getbbox()
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bord = min(dim[0], dim[1]) / 4 # a bit of a border
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im = im.crop((bbox[0] - bord, bbox[1] - bord, bbox[2] + bord, bbox[3] + bord))
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# and turn into black on white
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im = ImageOps.invert(im)
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# save the image, in format determined from filename
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im.save(file_name)
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def gen_subdir(basedir, md5hash, levels):
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"""Generate a subdirectory path out of the first _levels_
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characters of _hash_, and ensure the directories exist
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under _basedir_."""
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subdir = None
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for i in range(0, levels):
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char = md5hash[i]
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if subdir:
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subdir = os.path.join(subdir, char)
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else:
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subdir = char
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fulldir = os.path.join(basedir, subdir)
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if not os.path.exists(fulldir):
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os.mkdir(fulldir)
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return subdir
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def try_pick_word(words, badwordlist, verbose, nwords, min_length, max_length):
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if words is not None:
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word = words[random.randint(0, len(words) - 1)]
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while nwords > 1:
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word2 = words[random.randint(0, len(words) - 1)]
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word = word + word2
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nwords = nwords - 1
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else:
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word = ""
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max_length = max_length if max_length > 0 else 10
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for i in range(0, random.randint(min_length, max_length)):
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word = word + chr(97 + random.randint(0, 25))
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if verbose:
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print("word is %s" % word)
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if len(word) < min_length:
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if verbose:
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print(
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"skipping word pair '%s' because it has fewer than %d characters"
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% (word, min_length)
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)
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return None
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if max_length > 0 and len(word) > max_length:
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if verbose:
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print(
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"skipping word pair '%s' because it has more than %d characters"
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% (word, max_length)
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)
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return None
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if nonalpha.search(word):
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if verbose:
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print(
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"skipping word pair '%s' because it contains non-alphabetic characters"
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% word
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)
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return None
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for naughty in badwordlist:
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if naughty in word:
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if verbose:
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print(
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"skipping word pair '%s' because it contains word '%s'"
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% (word, naughty)
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)
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return None
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return word
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def pick_word(words, badwordlist, verbose, nwords, min_length, max_length):
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for x in range(
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1000
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): # If we can't find a valid combination in 1000 tries, just give up
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word = try_pick_word(
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words, badwordlist, verbose, nwords, min_length, max_length
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)
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if word:
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return word
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sys.exit("Unable to find valid word combinations")
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def read_wordlist(filename):
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if not os.path.isfile(filename):
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return []
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f = open(filename)
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words = [x.strip().lower() for x in f.readlines()]
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f.close()
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return words
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def run_in_thread(object):
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count = object[0]
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words = object[1]
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badwordlist = object[2]
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opts = object[3]
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font = object[4]
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fontsize = object[5]
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for i in range(count):
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word = pick_word(
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words,
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badwordlist,
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opts.verbose,
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opts.number_words,
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opts.min_length,
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opts.max_length,
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)
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salt = "%08x" % random.randrange(2**32)
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# 64 bits of hash is plenty for this purpose
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md5hash = hashlib.md5(
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(key + salt + word + key + salt).encode("utf-8")
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).hexdigest()[:16]
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filename = "image_%s_%s.png" % (salt, md5hash)
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if opts.dirs:
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subdir = gen_subdir(opts.output, md5hash, opts.dirs)
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filename = os.path.join(subdir, filename)
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if opts.verbose:
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print(filename)
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gen_captcha(word, font, fontsize, os.path.join(opts.output, filename))
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if __name__ == "__main__":
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"""This grabs random words from the dictionary 'words' (one
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word per line) and generates a captcha image for each one,
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with a keyed salted hash of the correct answer in the filename.
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To check a reply, hash it in the same way with the same salt and
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secret key, then compare with the hash value given.
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"""
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script_dir = os.path.dirname(os.path.realpath(__file__))
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parser = OptionParser()
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parser.add_option(
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"--wordlist", help="A list of words (required)", metavar="WORDS.txt"
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)
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parser.add_option(
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"--random",
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help="Use random characters instead of a wordlist",
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action="store_true",
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)
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parser.add_option(
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"--key", help="The passphrase set as $wgCaptchaSecret (required)", metavar="KEY"
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)
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parser.add_option(
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"--output",
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help="The directory to put the images in - $wgCaptchaDirectory (required)",
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metavar="DIR",
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)
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parser.add_option("--font", help="The font to use (required)", metavar="FONT.ttf")
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parser.add_option(
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"--font-size",
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help="The font size (default 40)",
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metavar="N",
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type="int",
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default=40,
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)
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parser.add_option(
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"--count",
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help="The maximum number of images to make (default 20)",
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metavar="N",
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type="int",
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default=20,
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)
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parser.add_option(
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"--badwordlist",
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help="A list of words that should not be used",
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metavar="FILE",
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default=os.path.join(script_dir, "badwordlist"),
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)
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parser.add_option(
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"--blacklist",
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help="DEPRECATED: list of words that should not be used",
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metavar="FILE",
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default=os.path.join(script_dir, "blacklist"),
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)
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parser.add_option(
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"--fill",
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help="Fill the output directory to contain N files, overrides count, cannot be used with --dirs",
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metavar="N",
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type="int",
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)
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parser.add_option(
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"--dirs",
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help="Put the images into subdirectories N levels deep - $wgCaptchaDirectoryLevels",
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metavar="N",
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type="int",
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)
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parser.add_option(
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"--verbose", "-v", help="Show debugging information", action="store_true"
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)
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parser.add_option(
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"--number-words",
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help="Number of words from the wordlist which make a captcha challenge (default 2)",
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type="int",
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default=2,
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)
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parser.add_option(
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"--min-length",
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help="Minimum length for a captcha challenge",
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type="int",
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default=1,
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)
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parser.add_option(
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"--max-length",
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help="Maximum length for a captcha challenge",
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type="int",
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default=-1,
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)
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parser.add_option(
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"--threads",
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help="Maximum number of threads to be used to generate captchas.",
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type="int",
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default=1,
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)
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opts, args = parser.parse_args()
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if opts.wordlist:
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wordlist = opts.wordlist
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elif opts.random:
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wordlist = None
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else:
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sys.exit("Need to specify a wordlist")
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if opts.key:
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key = opts.key
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else:
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sys.exit("Need to specify a key")
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if opts.output:
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output = opts.output
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else:
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sys.exit("Need to specify an output directory")
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if opts.font and os.path.exists(opts.font):
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font = opts.font
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else:
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sys.exit("Need to specify the location of a font")
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badwordlist = read_wordlist(opts.blacklist) + read_wordlist(opts.badwordlist)
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count = opts.count
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fill = opts.fill
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fontsize = opts.font_size
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threads = opts.threads
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if fill:
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count = max(0, fill - len(os.listdir(output)))
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words = None
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if wordlist:
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words = read_wordlist(wordlist)
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words = [
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x
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for x in words
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if len(x) in (4, 5) and x[0] != "f" and x[0] != x[1] and x[-1] != x[-2]
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]
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if count == 0:
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sys.exit("No need to generate CAPTCHA images.")
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if count < threads:
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chunks = 1
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threads = 1
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else:
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chunks = count // threads
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p = multiprocessing.Pool(threads)
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data = []
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print(
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"Generating %s CAPTCHA images separated in %s image(s) per chunk run by %s threads..."
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% (count, chunks, threads)
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)
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for i in range(0, threads):
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data.append([chunks, words, badwordlist, opts, font, fontsize])
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p.map(run_in_thread, data)
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