gistfile1.rb

class ApplicationController < ActionController::Base

  before_filter :authenticate_user!
  before_filter :authorize_admin
  rescue_from UserNotAuthorized, :with => :handle_auth_exception

  private
  
  def handle_auth_exception
    render :text => "401 Not Authorized", :status => :unauthorized
  end

  def authorize_admin
    raise UserNotAuthorized unless current_user.is_admin?
  end
end