UmnShibAuth is an authentication plugin for Rails designed to replace the existing UmnAuth x500 plugin for use with Shibboleth. This plugin should work for all versions of rails--it's been used in Rails 2 and 3.
Snag the code and drop it into vendor/plugins/umn_shib_auth
In application_controller.rb:
include UmnShibAuth::ControllerMethods
In your views:
<%= link_to "Sign out", shib_logout_url %>
<%= link_to "Sign in", shib_logout_in %>
In your controller:
before_filter :umn_auth_required
If you were using some flavor of the old UmnAuth filter linked from https://wiki.umn.edu/CAH/WebHome labeled "umn_auth for Rails 2.x (Joe Goggins).
You can do a one line migration, by removing the old code and adding the new code like follows
# include UmnAuth::ControllerMethods
include UmnShibAuth::ReplacementForUmnAuthControllerMethods
Copyright (c) 2011 Regents of the University of Minnesota