用户控制器渲染错误中的before_action:用户#show中的NoMethodError

Question

我正在关注Michael Hartl的Rails指南(第9章).当我尝试访问与用户配置文件对应的页面时,浏览器显示以下错误消息:

 NoMethodError in Users#show

Showing /home/jonathan/Desktop/railsTut/sample_app/app/views/users/show.html.erb where line #1 raised:

undefined method `name' for nil:NilClass

Extracted source (around line #1):

1: <% provide(:title, @user.name) %>
2: <div class="row">
3:   <aside class="span4">
4:     <section>

Rails.root: /home/jonathan/Desktop/railsTut/sample_app

这是我的users_controller.rb

class UsersController < ApplicationController
  before_action :signed_in_user, only: [:edit, :update]

  def show
    @user = User.find(params[:id])
    end

  def new
    @user = User.new
  end

  def create
    @user = User.new(params[:user])    # Not the final implementation!
    if @user.save
     sign_in @user
     flash[:success] = "Welcome to the Sample App!"
     redirect_to @user
    else
      render 'new'
    end
  end

  def edit
    @user = User.find(params[:id])
  end

  def update
    @user = User.find(params[:id])
    if @user.update_attributes(params[:user])
         flash[:success] = "Profile updated"
         sign_in @user
         redirect_to @user
      else
           render 'edit'
      end
    end

  def destroy
 User.find(params[:id]).destroy
    flash[:success] = "User destroyed."
    redirect_to users_url
    end

private

  def user_params
    params.require(:user).permit(:name, :email, :password, :password_confirmation)
    end


  # Before filters

  def signed_in_user
    unless signed_in?
        store_location
        redirect_to signin_url, notice: "Please sign in."
    end
 end
end

页面加载正常没有行:

before_action :signed_in_user, only: [:edit, :update]

但随着它的包含,事情出错了,我无法弄清楚为什么.

此外,这是routes.rb

SampleApp::Application.routes.draw do
  resources :users
  resources :sessions, only: [:new, :create, :destroy]

  root to: 'static_pages#home'

 match '/signup',  to: 'users#new'
  match '/signin',  to: 'sessions#new'
  match '/signout', to: 'sessions#destroy', via: :delete

  match '/help',    to: 'static_pages#help'
  match '/about',   to: 'static_pages#about'
  match '/contact', to: 'static_pages#contact'

end

任何帮助表示赞赏!

Answer 1

如果确实Hurman的答案解决了您的问题,原因是因为您运行的是旧版本(即<4.0.0)的rails.before_filter在此版本中重命名为before_action(https://github.com/rails/rails/commit/9d62e04838f01f5589fa50b0baa480d60c815e2c),Rails 4中的更多信息:before_filter vs. before_action

Answer 2

而不是在Users_controller中的Before Action尝试过滤之前所以你的代码如下所示:

before_filter :signed_in_user, only: [:edit, :update]

我有完全相同的错误!