The gen_captcha function generates an image containing text thatÂ’s easy for a human to read, but difficult for a computer. This allows you create a test to tell humans and computers apart. (requires PIL)
Python, 39 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 | import random
import Image
import ImageFont
import ImageDraw
import ImageFilter
def gen_captcha(text, fnt, fnt_sz, file_name, fmt='JPEG'):
"""Generate a captcha image"""
# randomly select the foreground color
fgcolor = random.randint(0,0xffff00)
# make the background color the opposite of fgcolor
bgcolor = fgcolor ^ 0xffffff
# create a font object
font = ImageFont.truetype(fnt,fnt_sz)
# determine dimensions of the text
dim = font.getsize(text)
# create a new image slightly larger that the text
im = Image.new('RGB', (dim[0]+5,dim[1]+5), bgcolor)
d = ImageDraw.Draw(im)
x, y = im.size
r = random.randint
# draw 100 random colored boxes on the background
for num in range(100):
d.rectangle((r(0,x),r(0,y),r(0,x),r(0,y)),fill=r(0,0xffffff))
# add the text to the image
d.text((3,3), text, font=font, fill=fgcolor)
im = im.filter(ImageFilter.EDGE_ENHANCE_MORE)
# save the image to a file
im.save(file_name, format=fmt)
if __name__ == '__main__':
"""Example: This grabs a random word from the dictionary 'words' (one
word per line) and generates a jpeg image named 'test.jpg' using
the truetype font 'porkys.ttf' with a font size of 25.
"""
words = open('words').readlines()
word = words[random.randint(1,len(words))]
gen_captcha(word.strip(), 'porkys.ttf', 25, "test.jpg")
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A CAPTCHA (Completely Automated Public Turing test to Tell Computers and Humans Apart) is a type of challenge and response test used tell humans and computers apart. This could be used to prevent "bots" from accessing online resources, taking part in online polls, signing up for free accounts, etc...
You must provide your own TrueType font(s); it works best if you use odd or irregular shaped fonts. You could even randomly choose a font for each captcha.
Tags: graphics
An alternative python captcha library. Check out the PyCaptcha library too. I have found it to be simple and extensible:
http://freshmeat.net/projects/pycaptcha/
dead. no pycaptcha projct on freshmeat; the ones I could find are all PHP.
http://sourceforge.net/projects/pycaptcha/. http://sourceforge.net/projects/pycaptcha/
An alternate method to generate the word. Instead of taking the word from dictionary it could be generated as follows:
The main function would change to
Not yet. It's not dead, the source is currently located here as it seems: http://svn.navi.cx/misc/trunk/pycaptcha/
Not yet. It's not dead, the source is currently located here as it seems: http://svn.navi.cx/misc/trunk/pycaptcha/
There is a problem in this line:
random.randint(1,len(words)) generates numbers between 1 and len(words), inclusive; so (1) it would never pick the first element (index 0), and (2) sometimes it would crash, when it tries to use index = len(words), which is past the end of the list