application_controller.rb

 # check that user is logged in
    def require_user
      logger.info "Require User"
      if current_user.nil?
        session[:link_back] = request.url
        redirect_to login_path
        false
      end
    end
    def require_user_no_linkback
      logger.info "Require User no linkback"
      if current_user.nil?
        redirect_to login_path
        false
      end
    end

windows_controller.rb

class WindowsController < ApplicationController
  before_filter :require_user_no_linkback, :except => [:index]
end