Support generation of random challenges instead of wordlist-based ones.

[toast/cookiecaptcha.git] / captcha.py

diff --git a/captcha.py b/captcha.py
index f1a050113461b677cf0f7c2fe38bac3f6eab3f1e..b30aebe1841882f438a075545a429af373f1a0f5 100644 (file)
--- a/captcha.py
+++ b/captcha.py
@@ -124,12 +124,32 @@ def gen_subdir(basedir, md5hash, levels):
                        os.mkdir(fulldir)
        return subdir
 
-def try_pick_word(words, blacklist, verbose):
-       word1 = words[random.randint(0,len(words)-1)]
-       word2 = words[random.randint(0,len(words)-1)]
-       word = word1+word2
+def try_pick_word(words, blacklist, verbose, nwords, min_length, max_length):
+       if words is not None:
+               word = words[random.randint(0,len(words)-1)]
+               while nwords > 1:
+                       word2 = words[random.randint(0,len(words)-1)]
+                       word = word + word2
+                       nwords = nwords - 1
+       else:
+               word = ''
+               max_length = max_length if max_length > 0 else 10
+               for i in range(0, random.randint(min_length, max_length)):
+                       word = word + chr(97 + random.randint(0,25))
+
        if verbose:
                print "word is %s" % word
+
+       if len(word) < min_length:
+               if verbose:
+                       print "skipping word pair '%s' because it has fewer than %d characters" % (word, min_length)
+               return None
+
+       if max_length > 0 and len(word) > max_length:
+               if verbose:
+                       print "skipping word pair '%s' because it has more than %d characters" % (word, max_length)
+               return None
+
        if nonalpha.search(word):
                if verbose:
                        print "skipping word pair '%s' because it contains non-alphabetic characters" % word
@@ -142,9 +162,9 @@ def try_pick_word(words, blacklist, verbose):
                        return None
        return word
 
-def pick_word(words, blacklist, verbose):
+def pick_word(words, blacklist, verbose, nwords, min_length, max_length):
        for x in range(1000): # If we can't find a valid combination in 1000 tries, just give up
-               word = try_pick_word(words, blacklist, verbose)
+               word = try_pick_word(words, blacklist, verbose, nwords, min_length, max_length)
                if word:
                        return word
        sys.exit("Unable to find valid word combinations")
@@ -162,6 +182,7 @@ if __name__ == '__main__':
        """
        parser = OptionParser()
        parser.add_option("--wordlist", help="A list of words (required)", metavar="WORDS.txt")
+       parser.add_option("--random", help="Use random charcters instead of a wordlist", action="store_true")
        parser.add_option("--key", help="The passphrase set as $wgCaptchaSecret (required)", metavar="KEY")
        parser.add_option("--output", help="The directory to put the images in - $wgCaptchaDirectory (required)", metavar="DIR")
        parser.add_option("--font", help="The font to use (required)", metavar="FONT.ttf")
@@ -170,12 +191,17 @@ if __name__ == '__main__':
        parser.add_option("--blacklist", help="A blacklist of words that should not be used", metavar="FILE")
        parser.add_option("--fill", help="Fill the output directory to contain N files, overrides count, cannot be used with --dirs", metavar="N", type='int')
        parser.add_option("--dirs", help="Put the images into subdirectories N levels deep - $wgCaptchaDirectoryLevels", metavar="N", type='int')
-       parser.add_option("--verbose", "-v", help="Show debugging information", action='store_true')    
+       parser.add_option("--verbose", "-v", help="Show debugging information", action='store_true')
+       parser.add_option("--number-words", help="Number of words from the wordlist which make a captcha challenge (default 2)", type='int', default=2)
+       parser.add_option("--min-length", help="Minimum length for a captcha challenge", type='int', default=1)
+       parser.add_option("--max-length", help="Maximum length for a captcha challenge", type='int', default=-1)
        
        opts, args = parser.parse_args()
 
        if opts.wordlist:
                wordlist = opts.wordlist
+       elif opts.random:
+               wordlist = None
        else:
                sys.exit("Need to specify a wordlist")
        if opts.key:
@@ -197,14 +223,16 @@ if __name__ == '__main__':
        dirs = opts.dirs
        verbose = opts.verbose
        fontsize = opts.font_size
-       
+
        if fill:
                count = max(0, fill - len(os.listdir(output)))
-       
-       words = read_wordlist(wordlist)
-       words = [x for x in words
-               if len(x) in (4,5) and x[0] != "f"
-               and x[0] != x[1] and x[-1] != x[-2]]
+
+       words = None
+       if wordlist:
+               words = read_wordlist(wordlist)
+               words = [x for x in words
+                       if len(x) in (4,5) and x[0] != "f"
+                       and x[0] != x[1] and x[-1] != x[-2]]
        
        if blacklistfile:
                blacklist = read_wordlist(blacklistfile)
@@ -212,7 +240,7 @@ if __name__ == '__main__':
                blacklist = []
        
        for i in range(count):
-               word = pick_word(words, blacklist, verbose)
+               word = pick_word(words, blacklist, verbose, opts.number_words, opts.min_length, opts.max_length)
                salt = "%08x" % random.randrange(2**32)
                # 64 bits of hash is plenty for this purpose
                md5hash = hashlib.md5(key+salt+word+key+salt).hexdigest()[:16]