Adding login.gatech.edu support to a Ruby on Rails v2.x app

1. Add gem dependency to rubycas-client gem (http://code.google.com/p/rubycas-client/).
   In config/environment.rb, inside Rails::Initializer block, add the following:

      config.gem "rubycas-client", :lib => 'casclient'

      
2. From the command line, install the gem by running:

      rake gems:install

      
3. Create a file config/initializers/cas.rb, containing:

 # CAS configuration require 'casclient'require 'casclient/frameworks/rails/filter'CASClient::Frameworks::Rails::Filter.configure(:cas_base_url  => "https://login.gatech.edu/cas/" )

   
   See the rubycas-client documentation (http://rubycas-client.rubyforge.org/) for
   more options for customizing the CAS client behavior.

4. In your ApplicationController class (app/controllers/application.rb), add 
  the following line:
  

      before_filter CASClient::Frameworks::Rails::Filter 

      
  Now once you restart your server, your entire app will be CASified, and any action
  will redirect to login.gatech.edu for authentication if the browser has not already
  been authenticated. After login, the user will be redirected back to your app. 
  The GT Account username of the logged in user will be available to your code in the session: 
  

      session[:cas_user]

  If you would like to only require login for specific controllers, you 
  can move the before_filter out of the ApplicationController, and into only 
  those controllers.  See the rails documentation for information on restricting 
  filters to specific actions.