devise_cosign_authenticatable

Written by Nat Budin
Taking a lot of inspiration from devise_ldap_authenticatable

devise_cosign_authenticatable is CoSign single sign-on support for Devise applications. It acts as a replacement for database_authenticatable. It builds on rubycas-client and should support just about any conformant CoSign server (although I have personally tested it using rubycas-server).

Requirements

• Rails 2.3 or greater (works with 3.x versions as well)
• Devise 1.0 or greater
• rubycas-client

Installation

gem install --pre devise_cosign_authenticatable

and in your config/environment.rb (on Rails 2.3):

config.gem 'devise', :version => '~> 1.0.6'
config.gem 'devise_cosign_authenticatable'

or Gemfile (Rails 3.x):

gem 'devise'
gem 'devise_cosign_authenticatable'

Setup

Once devise_cosign_authenticatable is installed, add the following to your user model:

devise :cosign_authenticatable

You can also add other modules such as token_authenticatable, trackable, etc. Please do not add database_authenticatable as this module is intended to replace it.

You'll also need to set up the database schema for this:

create_table :users do |t|
  t.string :username, :null => false
end

We also recommend putting a unique index on the username column:

add_index :users, :username, :unique => true

(Note: previously, devise_cosign_authenticatable recommended using a t.cosign_authenticatable method call to update the schema. Devise 2.0 has deprecated this type of schema building method, so we now recommend just adding the username string column as above. As of this writing, t.cosign_authenticatable still works, but throws a deprecation warning in Devise 2.0.)

Finally, you'll need to add some configuration to your config/initializers/devise.rb in order to tell your app how to talk to your CoSign server:

Devise.setup do |config|
  ...
  config.cosign_base_url = "https://cas.myorganization.com"
  
  # you can override these if you need to, but cosign_base_url is usually enough
  # config.cosign_login_url = "https://cas.myorganization.com/login"
  # config.cosign_logout_url = "https://cas.myorganization.com/logout"
  # config.cosign_validate_url = "https://cas.myorganization.com/serviceValidate"
  
  # The CoSign specification allows for the passing of a follow URL to be displayed when
  # a user logs out on the CoSign server. RubyCoSign-Server also supports redirecting to a
  # URL via the destination param. Set either of these urls and specify either nil,
  # 'destination' or 'follow' as the logout_url_param. If the urls are blank but
  # logout_url_param is set, a default will be detected for the service.
  # config.cosign_destination_url = 'https://cas.myorganization.com'
  # config.cosign_follow_url = 'https://cas.myorganization.com'
  # config.cosign_logout_url_param = nil

  # By default, devise_cosign_authenticatable will create users.  If you would rather
  # require user records to already exist locally before they can authenticate via
  # CoSign, uncomment the following line.
  # config.cosign_create_user = false

  # If you want to use the Devise Timeoutable module with single sign out, 
  # uncommenting this will redirect timeouts to the logout url, so that the CoSign can
  # take care of signing out the other serviced applocations. Note that each
  # application manages timeouts independently, so one application timing out will 
  # kill the session on all applications serviced by the CoSign.
  # config.warden do |manager|
  #   manager.failure_app = DeviseCosignAuthenticatable::SingleSignOut::WardenFailureApp
  # end
end

Extra attributes

If your CoSign server passes along extra attributes you'd like to save in your user records, using the CoSign extra_attributes parameter, you can define a method in your user model called cosign_extra_attributes= to accept these. For example:

class User < ActiveRecord::Base
  devise :cosign_authenticatable
  
  def cosign_extra_attributes=(extra_attributes)
    extra_attributes.each do |name, value|
      case name.to_sym
      when :fullname
        self.fullname = value
      when :email
        self.email = value
      end
    end
  end
end

See also

• CoSign
• rubycas-server
• rubycas-client
• Devise
• Warden

TODO

• Test on non-ActiveRecord ORMs

License

devise_cosign_authenticatable is released under the terms and conditions of the MIT license. See the LICENSE file for more information.