ruby on rails 3-simple_form_for错误:未定义的方法关联模型

Question

在我的rails应用程序中，我有两个相关的模型，称为Magazine和Article。

杂志

class Magazine < ActiveRecord::Base
  has_many :articles
end

文章

class Article < ActiveRecord::Base
  belongs_to :magazine
end

路线

Magazineapp::Application.routes.draw do
  resources :magazines do
    resources :articles
  end
end

schema.rb

create_table "articles", :force => true do |t|
  t.string   "title"
  t.string   "author"
  t.integer  "magazine_id"
  t.datetime "created_at"
  t.datetime "updated_at"
end
create_table "magazines", :force => true do |t|
  t.string   "title"
  t.datetime "created_at"
  t.datetime "updated_at"
end

我正在尝试从文章的新页面创建一篇与杂志关联的新论文。因此，我在杂志的展示页面上创建了一个链接，将选定的杂志传递到新文章的页面。

视图/杂志/show.html.erb

<p id="notice"><%= notice %></p>
<p>
  <b>Title:</b>
  <%= @magazine.title %>
</p>
<%= link_to 'Edit', edit_magazine_path(@magazine) %> |
<%= link_to 'Back', magazines_path %> |
<%= link_to 'New Article', new_magazine_article_path(@magazine) %>

在文章的新页面中呈现的部分是：

views/articles/_form.html.erb

<%= simple_form_for([@magazine, @article]) do |f| %>
  <%= f.error_notification %>
  <div class="inputs">
    <%= f.input :title %>
    <%= f.input :author %>
  </div>
  <div class="actions">
    <%= f.button :submit %>
  </div>
<% end %>

文章控制器的创建方法是：

def create
  @magazine = Magazine.find(params[:magazine_id])    
  @article = @magazine.articles.create(params[:article])
  respond_to do |format|
    if @article.save
      format.html { redirect_to(@article, :notice => 'Article was successfully created.') }
      format.xml  { render :xml => @article, :status => :created, :location => @article }
    else
      format.html { render :action => "new" }
      format.xml  { render :xml => @article.errors, :status => :unprocessable_entity }
    end
  end
end

但当我试图创建一篇与该杂志相关的新文章时，我收到了错误消息：

Showing /home/wilson/magazineapp/app/views/articles/_form.html.erb where line #1 raised:
undefined method `articles_path' for #<#<Class:0x00000001944070>:0x00000001926ed0>
Extracted source (around line #1):
1: <%= simple_form_for([@magazine, @article]) do |f| %>
2:   <%= f.error_notification %>
3: 
4:   <div class="inputs">
Request
Parameters:
{"magazine_id"=>"2"}

耙式路由

    magazine_articles GET    /magazines/:magazine_id/articles(.:format)          {:action=>"index", :controller=>"articles"}
                      POST   /magazines/:magazine_id/articles(.:format)          {:action=>"create", :controller=>"articles"}
 new_magazine_article GET    /magazines/:magazine_id/articles/new(.:format)      {:action=>"new", :controller=>"articles"}
edit_magazine_article GET    /magazines/:magazine_id/articles/:id/edit(.:format) {:action=>"edit", :controller=>"articles"}
     magazine_article GET    /magazines/:magazine_id/articles/:id(.:format)      {:action=>"show", :controller=>"articles"}
                      PUT    /magazines/:magazine_id/articles/:id(.:format)      {:action=>"update", :controller=>"articles"}
                      DELETE /magazines/:magazine_id/articles/:id(.:format)      {:action=>"destroy", :controller=>"articles"}
            magazines GET    /magazines(.:format)                                {:action=>"index", :controller=>"magazines"}
                      POST   /magazines(.:format)                                {:action=>"create", :controller=>"magazines"}
         new_magazine GET    /magazines/new(.:format)                            {:action=>"new", :controller=>"magazines"}
        edit_magazine GET    /magazines/:id/edit(.:format)                       {:action=>"edit", :controller=>"magazines"}
             magazine GET    /magazines/:id(.:format)                            {:action=>"show", :controller=>"magazines"}
                      PUT    /magazines/:id(.:format)                            {:action=>"update", :controller=>"magazines"}
                      DELETE /magazines/:id(.:format)                            {:action=>"destroy", :controller=>"magazines"}

我该如何解决这个问题？在这种情况下，传递给simple_form_for的正确参数是什么？

Answer 1

当您有嵌套的资源时，您必须确保始终在请求之间传递更高级别的资源。

您的路线将是您注意到的使用耙式路线的路线。

表单应该是这样的：

<%= simple_form_for([@magazine, @article]) do |f| %>
  <%= f.error_notification %>
  <div class="inputs">
    <%= f.input :title %>
    <%= f.input :author %>
  </div>    
  <div class="actions">
    <%= f.button :submit %>
  </div>
<% end %>

通过这种方式，现在你必须在文章控制器和文章视图页面上的任何地方使用新的路线，其中将包括杂志本身。

您在控制器中的创建操作将是：

def create
  @magazine = Magazine.find(params[:magazine_id])    
  @article = @magazine.articles.create(params[:article])
  respond_to do |format|
    if @article.save
      format.html { redirect_to([@magazine,@article], :notice => 'Article was successfully created.') }
      format.xml  { render :xml => @article, :status => :created, :location => @article }
    else
      format.html { render :action => "new" }
      format.xml  { render :xml => @article.errors, :status => :unprocessable_entity }
    end
  end
end

所以现在你所有的路线都应该参考@magazine。

Answer 2

在控制台中运行rake routes并确保articles_path存在。似乎应该命名为magazines_articles_path(...)