Recommendations for a captcha on Ruby on Rails

Question

I'd like to implement a captcha in a Rails project for a form submission, but I'm not sure what to go with. I'm inclining towards simplicity of implemention, and reliability when in use, over it being too sophisticated, as my application doesn't require too high a level of security.

Anyone have any recommendations?

Answer 1

The easiest way to add a CAPTCHA to your Rails application is using Ambethia reCAPTCHA:

1. Installation:

config.gem "ambethia-recaptcha", :lib => "recaptcha/rails", 
      :source => "http://gems.github.com"

You can install it as a plugin, too, if you like.

2. Get a reCAPTCHA account:

You have to create a reCAPTCHA key. You can do it on the reCAPTCHA site.

3. Usage:

Use recaptcha_tags to output the necessary HTML code and then verify the input with verify_recaptcha.

4. Further reading:

• Ambethia reCAPTCHA
• reCAPTCHA documentation

Answer 2

Installation

Add the following to your GEMFILE

gem "galetahub-simple_captcha", :require => "simple_captcha"

or

gem 'galetahub-simple_captcha', :require => 'simple_captcha',
    :git => 'git://github.com/galetahub/simple-captcha.git'

Then run bundle install if you're using Bundler (or use the package manager for your Rails configuration)

Setup

After installation, follow these simple steps to setup the plugin. The setup will depend on the version of rails your application is using.

rails generate simple_captcha
rake db:migrate

Usage

Controller Based

Add the following line in the file “app/controllers/application.rb”

ApplicationController < ActionController::Base
  include SimpleCaptcha::ControllerHelpers
end

In the view file within the form tags add this code

<%= show_simple_captcha %>

and in the controller’s action authenticate it as

if simple_captcha_valid?
  do this
else
  do that
end

Model Based

In the view file within the form tags add this code

<%= show_simple_captcha(:object=>"user") %>

and in the model class add this code

class User < ActiveRecord::Base
  apply_simple_captcha
end

FormBuilder helper

<%= form_for @user do |form| -%>
  ...
  <%= form.simple_captcha :label => "Enter numbers.." %>
  ...
<% end -%>

Validating with captcha

NOTE: @user.valid? will still work as it should, it will not validate the captcha code.

@user.valid_with_captcha?

Saving with captcha

NOTE: @user.save will still work as it should, it will not validate the captcha code.

@user.save_with_captcha

Formtastic integration

SimpleCaptcha detects if your use Formtastic and appends

“SimpleCaptcha::CustomFormBuilder”.

<%= form.input :captcha, :as => :simple_captcha %>

Options & Examples

View Options

*label* - provides the custom text b/w the image and the text field, the default is “type the code from the image”

*object* - the name of the object of the model class, to implement the model based captcha.

*code_type* - return numeric only if set to ‘numeric’

Global options

image_style - provides the specific image style for the captcha image.

There are eight different styles available with the plugin as…

1. simply_blue
2. simply_red
3. simply_green
4. charcoal_grey
5. embosed_silver
6. all_black
7. distorted_black
8. almost_invisible

Default style is ‘simply_blue’. You can also specify ‘random’ to select the random image style.

distortion - handles the complexity of the image. The :distortion can be set to ‘low’, ‘medium’ or ‘high’. Default is ‘low’.

*Create “rails_root/config/initializers/simple_captcha.rb”*

SimpleCaptcha.setup do |sc|
  # default: 100x28
  sc.image_size = '120x40'

  # default: 5
  sc.length = 6

  # default: simply_blue
  # possible values:
  # 'embosed_silver',
  # 'simply_red',
  # 'simply_green',
  # 'simply_blue',
  # 'distorted_black',
  # 'all_black',
  # 'charcoal_grey',
  # 'almost_invisible'
  # 'random'
  sc.image_style = 'simply_green'

  # default: low
  # possible values: 'low', 'medium', 'high', 'random'
  sc.distortion = 'medium'
end

You can add your own style:

SimpleCaptcha.setup do |sc|
  sc.image_style = 'mycaptha'
  sc.add_image_style('mycaptha', [
      "-background '#F4F7F8'",
      "-fill '#86818B'",
      "-border 1",
      "-bordercolor '#E0E2E3'"])
end

You can provide the path where image_magick is installed as well:

SimpleCaptcha.setup do |sc|
  sc.image_magick_path = '/usr/bin' # you can check this from console by running: which convert
end

You can provide the path where should be stored tmp files. It’s usefull when you dont have acces to /tmp (default directory)

SimpleCaptcha.setup do |sc|
  sc.tmp_path = '/tmp' # or somewhere in project eg. Rails.root.join('tmp/simple_captcha').to_s, make shure directory exists
end

How to change the CSS for SimpleCaptcha DOM elements?

You can change the CSS of the SimpleCaptcha DOM elements as per your need in this file.

*/app/views/simple_captcha/_simple_captcha.erb*

View’s Examples

Controller Based Example

<%= show_simple_captcha %>

<%= show_simple_captcha(:label => "human authentication") %>

Model Based Example

<%= show_simple_captcha(:object => 'user', :label => "human authentication") %>

Model Options

message - provides the custom message on failure of captcha authentication the default is “Secret Code did not match with the Image”

add_to_base - if set to true, appends the error message to the base.

Model’s Example

class User < ActiveRecord::Base
  apply_simple_captcha
end

class User < ActiveRecord::Base
  apply_simple_captcha :message => "The secret Image and code were different", :add_to_base => true
end

Answer 3

Well, ReCaptcha will do the job and there are many tutorials on it online.

However, you have to write a correct "def create" (create method) in your controller that will pass whatever is in your form plus validate Recaptcha at the same time. Then it will work nicely.

There was one little problem with it. After I inserted ReCaptcha into my form, the form validation stopped working. However, it can be fixed with an easy code inserted into the model file:

after_validation :on => :create 

(:create = is the "def create" method in your controller). It will force the form to validate the form first and then validate Recaptcha.

Answer 4

I've used Recaptcha in one of my PHP project. http://recaptcha.net/
According to the site, it also has plugins for Ruby (http://recaptcha.net/resources.html). Although first ruby link didn't work, next link still works. http://svn.ambethia.com/pub/rails/plugins/recaptcha/ Check it.

Answer 5

I've used ambethia recapchat for rails application. it most easy than other

Answer 6

reCAPTCHA for rails is great, in terms of functionality. However, if you require XHTML validation, RUN AWAY! This plugin does not (and probably never will) validate. I find it embarrassing that only one page on my entire site does not validate - it is the page with reCAPTCHA. If there was ANY other choice, I would take it.

Answer 7

if you're after a CAPTCHA that validates, and is (almost) as easy to use as reCAPTCHA, please give my SlideCAPTCHA a try. (Wrote it a few days ago, needs some tests in real-life usage.) I based its deployment process on the reCAPTCHA plugin, but you can style it with CSS.

It does require Ruby/GD, however, so if you don't have GD already, I can't promise that GD is easy to install and use!