host_based_routing.rb

# Host based routing - enables routes like:
# map.connect '', :controller => 'blah', :action => 'blah', :conditions => {:host => 'blah'}
#
# Put this file in /config/initializers

module ActionController
  module Routing
    class Route
      def recognition_conditions_with_host
        result = recognition_conditions_without_host
        result << 'conditions[:host] === env[:host]' if conditions[:host]
        result
      end
      alias_method_chain :recognition_conditions, :host
    end
  end
end