ruby-on-rails - :authenticate_user！功能不工作

Question

我在 ruby​​-on-rails 项目中使用设计，before_filter :authenticate_user!, :only => [:show]当我在 UsersController 中使用它时不起作用：

# ./controllers/users_controller.rb
class UsersController < Devise::SessionsController
  before_filter :authenticate_user!, :only => [:show]

  def show
  end
end

# ./config/routes.rb
Notify::Application.routes.draw do
   devise_for :users 
  ...
end