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Smart Captcha Automation
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LICENSE Added a license and wrote some of the README Mar 8, 2011
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Adding captchas to some action should be really easy. It shouldn't require a migration, like Brain Buster or API calls like reCAPTCHA. Gotcha is an easy way to ask (custom) questions of your users in order for them to perform some action (like submitting a form).


To install Gotcha, just run:

$ gem install gotcha

Or put it in your Gemfile

gem 'gotcha'

Built-in Gotchas

There are a few captchas implemented and installed by default:

  • SumGotcha - Two random numbers, ask the user for the sum of them
  • BackwardGotcha - Ask the user to retype a random string backwards (case-insensitive)

A random Gotcha type will be generated on each call to gotcha

Using Gotcha

In your forms (HAML used for brevity):

= form_for @thing do |f|
  = gotcha_error
  = gotcha
  = f.submit

In your controller

def new
  @thing =

def create
  @thing =[:thing])
  if gotcha_valid? &&
    redirect_to @thing
    render :new

Multiple Gotchas in a page?

= form_for @thing do |f|
  = gotcha_error
  - 10.times do
    .gotcha= gotcha
  = f.submit

and in your controller


Writing your own Gotchas

To write your own Gotcha, all you have to do is extend Gotcha::Base and provide a question and an answer:

class MyGotcha < Gotcha::Base
  def initialize
    @question = 'Who made this?'
    @answer = 'john'

When writing your own gotchas, you may want the answers to be able to flex a bit, like allowing users to enter things in different cases. In that case, your Gotcha can just override self.down_transform with whatever logic you want. It takes a single argument, text which is the text of the answer. You are expected to put it in a form that it would match regardless of the cases you want. By default, self.down_transform is implemented as:

def self.down_transform(text)
  text = text.is_a?(String) ? text.dup : text.to_s
  text.gsub!(/\s+/, ' ')

Meaning by default, space types don't matter - and case is insensitive.

Installing your gotchas

In an initializer:

Gotcha.unregister_all_types # Remove pre-defined
Gotcha.register_type SumGotcha

Determine if the gotcha was valid

You have a few ways to determine whether or not a Gotcha was valid. You can use gotcha_valid? in views and controllers, or use validate_gotcha! (which throws a Gotcha::ValidationException if the Gotcha was not valid) in your controllers.


In testing, it's sometimes useful to make validation always return true. For this, you can use: Gotcha.skip_validation = true


MIT License. See attached

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