Question

我将跟着Michael Hartl Chapter 13的rails教程一起学习，但是我不是在制作微博，而是在创作动物。

我的动物视图显示了一个“删除”超链接，该超链接应该从我的列表中删除动物记录，但是视图操作似乎根本无法使用destroy方法。
我通读了类似帖子here中的所有答案，但没有找到对我的情况有帮助的答案。

按照教程中的说明，我目前在AWS cloud9上的开发环境中。我非常感谢任何指针，因为我已经为此奋斗了几天。

这是我的视图代码：

<li id="animal-<%= animal.id %>">
  <%= link_to gravatar_for(animal.user, size: 50), animal.user %>
  <span class="user"><%= link_to animal.user.name, animal.user %></span>
  <span class="ear_tag"><%= animal.ear_tag %></span>
  <span class="timestamp">
    Posted <%= time_ago_in_words(animal.created_at) %> ago.
    <% if current_user?(animal.user) %>
      <%= link_to "delete", animal, method: :delete, data: { confirm: "You sure?" } %>
    <% end %>
  </span>
</li>

此视图是从供稿视图调用的：

<% if @feed_items.any? %>
  <ol class="animals">
    <%= render @feed_items %>
  </ol>
  <%= will_paginate @feed_items %>
<% end %>

哪个来自主页视图：

<div class="col-md-8">
  <h3>Animal Feed</h3>
  <%= render 'shared/feed' %>
</div>

我对<%= link_to...行进行了多次审查，这似乎是正确的。我的控制器代码是：

class AnimalsController < ApplicationController
  before_action :logged_in_user,  only: [:create, :destroy]
  before_action :correct_user,    only: :destroy

  def destroy
    @animal.destroy
    flash[:success] = "Animal deleted"
    redirect_to request.referrer || root_url
  end

  def correct_user
    @animal = current_user.animals.find_by(id: params[:id])
    redirect_to root_url if @animals.nil?
  end
end

我注意到我从来没有看到闪烁的“动物已删除”，这告诉我在控制器方法中我可能还没到那点。

我的模型代码是：

class Animal < ApplicationRecord
  belongs_to :user
  default_scope -> {order(created_at: :desc) }
  validates :user_id, presence: true
  validates :ear_tag, presence: true, length: {maximum: 20}
end

这是我来自app / assets / javascripts的application.js文件：

//= require jquery
//= require bootstrap
//= require rails-ujs
//= require turbolinks
//= require_tree

在浏览器的渲染视图中单击“删除”标签后，服务器日志显示的内容如下：

Started DELETE "/animals/308" for 23.25.133.17 at 2018-09-06 21:11:06 +0000
Processing by AnimalsController#destroy as HTML
  Parameters: {"authenticity_token"=>"vwF6cWow+6B3BxOiJElVY0aQmMGr4WLWDOCxgB0C03nRLcQDKC3YCUqBr4ahVwlSKN7bEYRrmGytyI1fPgvavw==", "id"=>"308"}
  User Load (0.1ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT ?  [["id", 102], ["LIMIT", 1]]
  Animal Load (0.2ms)  SELECT  "animals".* FROM "animals" WHERE "animals"."user_id" = ? AND "animals"."id" = ? ORDER BY "animals"."created_at" DESC LIMIT ?  [["user_id", 102], ["id", 308], ["LIMIT", 1]]
Redirected to https://cabfa13dd4f34e67b634d4f52a7a046f.vfs.cloud9.us-west-2.amazonaws.com/
Filter chain halted as :correct_user rendered or redirected
Completed 302 Found in 4ms (ActiveRecord: 0.3ms)

我还发现我的一项测试失败了：

FAIL["test_animal_interface", AnimalsInterfaceTest, 1.5248641059999954]
 test_animal_interface#AnimalsInterfaceTest (1.53s)
        "Animal.count" didn't change by -1.
        Expected: 38
          Actual: 39
        test/integration/animals_interface_test.rb:33:in `block in <class:AnimalsInterfaceTest>'

Answer 1

由于：correct_user呈现或重定向，过滤器链暂停

问题是您有@animals（未定义 ），而不是@animal，所以redirect_to root_url if @animals.nil? 总是成功，这导致销毁操作总是失败。您应该将@animals更改为@animal

def correct_user
  @animal = current_user.animals.find_by(id: params[:id])
  redirect_to root_url if @animal.nil?
end

link_to'删除'不会破坏记录

1 个答案: