I need a captcha in a form, whose associated model is a Validatable. After googling, I decided to go with Simple Captcha. The Simple captcha is extremely easy to use, see its documentation, you’ll know. But it works fine with a ActiveRecord::Base, not a Validatable. There has to be some hack to make it work. I could use “Controller mode” of it. But it will be nice to put it into model, make it part of validation process. and here’s my code:

First, include SimpleCaptcha into your Validatable model:

YourValidatable.module_eval do
    class << self; include SimpleCaptcha::ModelHelpers; end
end

And overwrite apply_simple_captcha

  def self.apply_simple_captcha(options = {})
    module_eval do
      require 'pstore'
      include SimpleCaptcha::ConfigTasks
      attr_accessor :captcha, :captcha_code,
      :authenticate_with_captcha
      alias_method :valid_without_captcha?, :valid?
    end
    @captcha_invalid_message =
 (options[:message].nil? || options[:message].empty?) ?
  " image did not match with text" : options[:message]
    module_eval(turing_valid_method)
    module_eval(turing_save_method)
  end

Finally, call apply_simple_captcha

That’s it.

In the controller, instead of calling valid? to decide if the object is valid, you call valid_with_captcha?

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