Austin said:
Jamis,
What did you use to do that captcha? That captcha I might actually
support using; I just don't want to do an image-based captcha because
of accessibility issues.
-austin
Just Ruby. In my blog-comments.rb file, I've got a method 'captcha' that
returns the captcha block as HTML, expecting to be wrapped in a form:
def captcha
source = "23456789abdefghijkmnpqr" +
"stuvwxyzABDEFGHJKLMNPQR" +
"STUVWXYZ!?%\#@&*:\"<>".split(//)
source = source.sort_by { rand }
chars = (1..10).collect { source.shift }
string = chars.join
md5hash = MD5.hexdigest( string )
captcha_string = chars.reverse.collect { |i|
"<span>#{i}</span> " }.join
<<-EOF
<p>
Type the following characters <strong>in reverse
order</strong> into the text box. Spaces are optional.
</p>
<div class="captcha">
#{captcha_string}
</div>
<input type="hidden" name="checksum" value="#{md5hash}" />
What characters did you see:
<input type="text" name="captcha" value="" />
EOF
end
Then, when the form is submitted, I call 'validate_captcha':
def validate_captcha
checksum = @session['checksum']
captcha = @session['captcha']
sum = MD5.hexdigest( captcha.gsub(/\s/,"") )
sum == checksum
end
If this returns true, they entered the captcha string correctly. Like I
said, it's pretty simple, and easily circumvented, but it's worked well
for me so far.
(The above code is in the public domain, so do with it as you will.)
))