Authenticate as remote user - Ruby on Rails Plugins
Authenticate as remote user Plugin

Plugin Details

      Provides a simple intereface to various Apache authentication systems to allow your Rails application to find out the currently logged in user. The plugin interface is similar to the Acts As Authenticated plugin, but it does no actual authentication.

Install Authenticate as remote user Plugin

ruby script/plugin install http://craz8.com/svn/trunk/plugins/authenticate_as_remote_user/