Casrack the Authenticator is a
Rack[http://github.com/chneukirchen/rack] middleware
that provides CAS[http://www.jasig.org/cas] support.

As of the current version, Casrack the Authenticator only supports the most basic
of CAS scenarios: it requires CAS authentication if it receives a 401 Unauthorized
response from lower-down in the Rack stack, and it stores the authentication token
in the session (so logout happens when users close their browers).  Casrack the Authenticator
is a very open-minded beast, though, so please contribute (well-tested) additions to do
proxy-authentication and single-sign-out, or for anything else you desire.

=== How-To

==== 1: install

  [sudo] gem install casrack_the_authenticator

==== 2: set up the middleware:

  # in your rackup:
  use CasrackTheAuthenticator::Simple, :cas_server => "http://cas.mycompany.com/cas"
  # or "config.middleware.use" if you're on Rails
  
See CasrackTheAuthenticator::Configuration for specifics on that Hash argument.

==== 3: optionally install CasrackTheAuthenticator::RequireCAS if you want _every_ request to require CAS authentication:
   
  # in your rackup:
  use CasrackTheAuthenticator::Simple, :cas_server => ...
  use CasrackTheAuthenticator::RequireCAS
  # or "config.middleware.use" if you're on Rails
   
==== 4: pull the authenticated CAS username out of the Rack session:

  # in a Rack app:
  def call(env)
    user = cas_user(env)
    ...
  end
  
  def cas_user(env)
    username = Rack::Request.new(env).session[CasrackTheAuthenticator::USERNAME_PARAM]
    User.find_by_username(username)
  end
  
  # or, in a Rails controller:
  
  def cas_user
    username = Rack::Request.new(request.env).session[CasrackTheAuthenticator::USERNAME_PARAM]
    User.find_by_username(username)
  end