Yacaph, which stands for "Yet Another CAPtcha Helper". It’s a lean and mean captcha processor. The reason it’s lean is because it doesn’t need to create images on the fly nor store any information in the users session. Everything required to validate the captcha is provided by the user request.

Using Yacaph is a five step process

  1. Install RMagick
  2. Install the plugin
  3. Generate a bunch of images off-line
  4. Use the helper method(s)
  5. Validate user input

Install the RMagic

Follow the instructions on their site: http://rmagick.rubyforge.org/install-faq.html

Install the Plugin

Installing the plugin is as simple as issuing this command from the root of your rails application directory:

  script/plugin install svn://rubyforge.org//var/svn/yacaph/trunk

Generate a bunch of images off-line

The reason why you don’t need to generate images on the fly is that they have been generated in advance and all you do is pick one at random. To do this you run the rake task:

   rake yacaph:generate COUNT=250

This will create the ’/public/images/captcha’ directory if it doesn’t already exist and put 250 randomly generated captcha gifs. This can take a while so you might as well get something to drink. Feel free to toy around with the settings within the yacaph.rb file to get just the right look/size for your images.

Use the helper methods

In your forms all you need to do is:

  <%= yacaph_block %>

and add a little bit of CSS styling to get a nice looking captcha validation text field and image. If you don’t like the way it’s setup then use the other helper methods, which are more granular.

Validate user input

In your controller, you will need to do the following:

PostController < ApplicationController

   include YacaphHelper

   def create
      ...
      if yacaph_validated?
         ...
      else
         ...
      end
   end

end

That’s it. Did I tell you that it flies? It’s really fast (of course it’s got nothing to do!)

Enjoy!

Copyright © 2007 Eric Methot, released under the MIT license