--- nospam.py.orig 2006-04-14 14:12:17.000000000 -0400 +++ nospam.py 2006-09-23 13:01:05.691442716 -0400 @@ -3,8 +3,8 @@ Based on a idea and ref impl of Jesus Roncero Franco . Implemented as a pyblosxom plugin by Steven Armstrong . -Creates a random number, generates an image of it, and stores the number -in the session. Then compares the number the user entered in the comment +Creates a random string, generates an image of it, and stores the string +in the session. Then compares the string the user entered in the comment form with the one stored in the session. Rejects the comment if they don't match. @@ -38,8 +38,8 @@ Add something like this to your comment-form.html template: -Secret Number Image - +Secret Number Image + Dependecies: @@ -61,6 +61,9 @@ import sys import os import random +import string +import math + from Pyblosxom import tools # PIL imports http://www.pythonware.com/products/pil/ @@ -68,6 +71,7 @@ import Image import ImageDraw import ImageOps + import ImageEnhance try: import ImageFont except ImportError: @@ -82,7 +86,7 @@ _bgColor = (255,255,255) # White _gridInk = (200,200,200) _fontInk = (130,130,130) -_fontSize = 14 +_fontSize = 32 # set in cb_start callback _fontPath = None @@ -146,10 +150,63 @@ return retval +# this function is (c) Benjamin Mako Hill +# generate the unqiue string +def _generateString(): + import string + import random + + chars = string.ascii_lowercase + string.digits + secret_string = "" + + # generate a string that is 5-7 characters long + string_len = random.randint(5,7) + + while (len(secret_string) < string_len ): + char = chars[random.randint(0,35)] + + # skip a number of potentially confusable characters + if char in ['l', '1', 'i', 'j', 'o', '0', 'u', 'v', 'd', '5', 's', 'f', 't' ]: + continue + secret_string += char + return secret_string + +# This function is (c) Neil Harris +# Taken from Mediawiki's ConfirmEdit extension's captcha.py +# Modified and incorporated by Benjamin Mako Hill +# +# Does X-axis wobbly copy, sandwiched between two rotates +def _wobbly_copy(src, wob, col, scale, ang): + x, y = src.size + f = random.uniform(4*scale, 5*scale) + p = random.uniform(0, math.pi*2) + rr = ang+random.uniform(-30, 30) # vary, but not too much + int_d = Image.new('RGB', src.size, 0) # a black rectangle + rot = src.rotate(rr, Image.BILINEAR) + # Do a cheap bounding-box op here to try to limit work below + bbx = rot.getbbox() + if bbx == None: + print "whoops" + return src + else: + l, t, r, b= bbx -# This function is (c) Jesus Roncero Franco . -# Modified to support old and new PIL versions by Steven Armstrong. -def _generateImage(number): + # and only do lines with content on + for i in range(t, b+1): + # Drop a scan line in + xoff = int(math.sin(p+(i*f/y))*wob) + xoff += int(random.uniform(-wob*0.5, wob*0.5)) + int_d.paste(rot.crop((0, i, x, i+1)), (xoff, i)) + + # try to stop blurring from building up + int_d = int_d.rotate(-rr, Image.BILINEAR) + enh = ImageEnhance.Sharpness(int_d) + return enh.enhance(2) + +# This function is (c) Neil Harris +# Taken from Mediawiki's ConfirmEdit extension's captcha.py +# Modified and incorporated by Benjamin Mako Hill +def _generateImage(text): try: # recent PIL version with support for truetype fonts font = ImageFont.truetype(_fontPath, _fontSize) @@ -157,48 +214,52 @@ # old PIL version, fallback to pil fonts font = ImageFont.load(_fontPath) - img = Image.new("RGB", _imageSize, _bgColor) - draw = ImageDraw.Draw(img) - - xsize, ysize = img.size - - # Do we want the grid start at 0,0 or want some offset? - x, y = 0,0 - - while x <= xsize: - try: - # recent PIL version - draw.line(((x, 0), (x, ysize)), fill=_gridInk) - except TypeError: - # old PIL version - draw.setink(_gridInk) - draw.line(((x, 0), (x, ysize))) - x = x + _xstep - while y <= ysize: - try: - draw.line(((0, y), (xsize, y)), fill=_gridInk) - except TypeError: - draw.setink(_gridInk) - draw.line(((0, y), (xsize, y))) - y = y + _ystep - - try: - draw.text((10, 2), number, font=font, fill=_fontInk) - except TypeError: - draw.setink(_fontInk) - draw.text((10, 2), number, font=font) + """Generate a captcha image""" + # white text on a black background + bgcolor = 0x0 + fgcolor = 0xffffff + + # determine dimensions of the text + dim = font.getsize(text) + + # create a new image significantly larger that the text + edge = max(dim[0], dim[1]) + 2*min(dim[0], dim[1]) + + im = Image.new('RGB', (edge, edge), bgcolor) + d = ImageDraw.Draw(im) + x, y = im.size + # add the text to the image + d.text((x/2-dim[0]/2, y/2-dim[1]/2), text, font=font, fill=fgcolor) + k = 3 + wob = 0.20*dim[1]/k + rot = 45 + # Apply lots of small stirring operations, rather than a few large ones + # in order to get some uniformity of treatment, whilst + # maintaining randomness + for i in range(k): + im = _wobbly_copy(im, wob, bgcolor, i*2+3, rot+0) + im = _wobbly_copy(im, wob, bgcolor, i*2+1, rot+45) + im = _wobbly_copy(im, wob, bgcolor, i*2+2, rot+90) + rot += 30 + + # now get the bounding box of the nonzero parts of the image + bbox = im.getbbox() + bord = min(dim[0], dim[1])/4 # a bit of a border + im = im.crop((bbox[0]-bord, bbox[1]-bord, bbox[2]+bord, bbox[3]+bord)) + # and turn into black on white + im = ImageOps.invert(im) - return img + return(im) def _writeImage(request): - number = str(random.randrange(1,99999,1)) + secret_string = _generateString() session = request.getSession() - session["nospam"] = number + session["nospam"] = secret_string session.save() - image = _generateImage(number) + image = _generateImage(secret_string) response = request.getResponse() response.addHeader('Content-Type', 'image/png') @@ -259,7 +320,7 @@ def cb_comment_reject(args): """ - Checks if the the nospam number of the incomming request + Checks if the the nospam code of the incoming request matches the one stored in the session. Creates a template variable $cmt_nospam_error with a error message if it didn't. @@ -285,11 +346,11 @@ allow_trackback = config.get('nospam_allow_trackback', 0) try: - nospam = int(form["nospam"].value) - sess_nospam = int(session["nospam"]) + nospam = form["nospam"].value + sess_nospam = session["nospam"] except: - nospam = 0 - sess_nospam = 1 + nospam = "0" + sess_nospam = "1" if allow_trackback: comment = args['comment'] @@ -300,7 +361,7 @@ if nospam != sess_nospam: _remember_comment(request) - data["cmt_nospam_error"] = "Secret number did not match." + data["cmt_nospam_error"] = "Secret code did not match." return True else: _forget_comment(request)