SessionCaptcha¶ ↑

SessionCaptcha is an easy to use CAPTCHA plugin that uses the session to temporarily store the hashed value of the generated secret. The secret and image are securely destroyed after completion of the transaction.

Requirements¶ ↑

• Ruby >= 1.8.7

• Rails >= 3

• ImageMagick should be installed on your machine to use this plugin. visit www.imagemagick.org/script/index.php for more details.

Installation¶ ↑

gem ‘session_captcha’, :git => ‘git://github.com/trimentor/session_captcha.git’

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 session_captcha

The following files will be created

config/initializers/session_captcha.rb
app/views/session_captcha/_session_captcha.rb

The initializer “config/initializers/session_captcha.rb” will contain a randomly generated salt. Create your own salt with for example a program like pwgen (Linux).

pwgen -s -y -n 64 1

Usage¶ ↑

Add the following line in the controller where you want to generate a CAPTCHA and verify user input

include SessionCaptcha::ControllerHelpers

Next add a route in the file routes.rb for the controller action generate_captcha.

In the view file within the form tag add this code

<%= show_session_captcha generate_captcha_url %>

and in the controller’s action authenticate it as

if session_captcha_valid?
  do this
else
  do that
end

Options¶ ↑

Controller Options¶ ↑

• code - return ‘alfanumeric’ or ‘numeric’ only

Default is ‘alfanumeric’. Overrule the controller action generate_captcha to change it.

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

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/session_captcha.rb”

SessionCaptcha.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:

SessionCaptcha.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:

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

How to change the CSS for SessionCaptcha DOM elements?¶ ↑

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

/app/views/session_captcha/_session_captcha.erb

Bug Tracker¶ ↑

Have a bug? Please create an issue here on GitHub!

github.com/trimentor/session_captcha/issues

Authors¶ ↑

• Author : Sur

• *Rails 3 Plugin* : Igor Galeta

• SessionCaptcha : Kjel Delaey

Copyright and License¶ ↑

Copyright © 2008 Sur

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.