Question

所以我有两个模型Topic，Client。客户has_and_belongs_to_many :topics和主题has_and_belongs_to_many :clients。

基本上，我想要发生的事情是...当有人去我的Topic#index时，取决于他们如何到达那里（即通过client/:id/topics或/topics），我想要创造和放大的行为新的不同。即在/topics，它只是创建一个主题。在client/:id/topics，它会创建一个主题并将其分配给该客户。

我的路线看起来像这样：

  resources :topics
  resources :clients do
    resources :topics
  end

My Topics Controller看起来像这样：

  def new
        if params[:client_id]
            @client = Client.find(params[:client_id])
            @topic = @client.topics.build
        else
            @topic = Topic.new
        end

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @topic }
    end
  end

  def create
        if params[:client_id]
            @client = Client.find(params[:client_id])
            @topic = @client.topics.build(params[:topic])
        else
        @topic = Topic.new(params[:topic])
        end

    respond_to do |format|
      if @topic.save
        format.html { redirect_to @topic, notice: 'Topic was successfully created.' }
        format.json { render json: @topic, status: :created, location: @topic }
      else
        format.html { render action: "new" }
        format.json { render json: @topic.errors, status: :unprocessable_entity }
      end
    end
  end

我的views/topics/_form.html.erb看起来像这样：

<%= form_for([@client, @topic]) do |f| %>
...
<% end %>

但是，当我从client/:id/topics执行操作时，这就是日志的样子：

Started GET "/clients/1/topics/new" for 127.0.0.1 at 2012-09-10 14:33:06 -0500
Processing by TopicsController#new as HTML
  Parameters: {"client_id"=>"1"}
  Client Load (0.2ms)  SELECT "clients".* FROM "clients" WHERE "clients"."id" = ? LIMIT 1  [["id", "1"]]
  Rendered topics/_form.html.erb (3.6ms)
  Rendered topics/new.html.erb within layouts/application (4.7ms)
  User Load (0.3ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 1 LIMIT 1
   (0.2ms)  SELECT COUNT(*) FROM "roles" INNER JOIN "users_roles" ON "roles"."id" = "users_roles"."role_id" WHERE "users_roles"."user_id" = 1 AND (((roles.name = 'admin') AND (roles.resource_type IS NULL) AND (roles.resource_id IS NULL)))
  Rendered layouts/_navigation.html.erb (7.2ms)
  Rendered layouts/_messages.html.erb (0.1ms)
Completed 200 OK in 61ms (Views: 57.0ms | ActiveRecord: 0.7ms)

看起来不错......这里的一切似乎都井井有条。但是在POST中似乎没有工作：

Started POST "/clients/1/topics" for 127.0.0.1 at 2012-09-10 14:33:13 -0500
Processing by TopicsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"J172LuZQPv8=", "topic"=>{"name"=>"AMZN"}, "commit"=>"Create Topic", "client_id"=>"1"}
  Client Load (0.2ms)  SELECT "clients".* FROM "clients" WHERE "clients"."id" = ? LIMIT 1  [["id", "1"]]
   (0.1ms)  begin transaction
  SQL (186.2ms)  INSERT INTO "topics" ("created_at", "name", "updated_at") VALUES (?, ?, ?)  [["created_at", Mon, 10 Sep 2012 19:33:13 UTC +00:00], ["name", "AMZN"], ["updated_at", Mon, 10 Sep 2012 19:33:13 UTC +00:00]]
   (4.6ms)  commit transaction
Redirected to http://localhost:3000/topics/4
Completed 302 Found in 198ms (ActiveRecord: 191.1ms)

您会注意到没有为客户分配新主题。

我错过了什么？

谢谢！

修改1

添加了将调试语句放到我的创建操作中，这是我在执行POST操作后得到的结果 - 这表明获得了params[:client_id]而不仅仅是params[:id]：

Served asset /application.js - 304 Not Modified (1ms)
**************************************************
This is the params[:client_id] => {3}
**************************************************
This is the params[:id] => {}


Started POST "/clients/3/topics" for 127.0.0.1 at 2012-09-10 15:06:31 -0500
Processing by TopicsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"J172LuZQc5NYoiMSzDD3oY9vGmxxCX0OdxcGm4GSPv8=", "topic"=>{"name"=>"TEST2"}, "commit"=>"Create Topic", "client_id"=>"3"}
  Client Load (0.2ms)  SELECT "clients".* FROM "clients" WHERE "clients"."id" = ? LIMIT 1  [["id", "3"]]
   (0.1ms)  begin transaction
  SQL (0.7ms)  INSERT INTO "topics" ("created_at", "name", "updated_at") VALUES (?, ?, ?)  [["created_at", Mon, 10 Sep 2012 20:06:31 UTC +00:00], ["name", "TEST2"], ["updated_at", Mon, 10 Sep 2012 20:06:31 UTC +00:00]]
   (3.3ms)  commit transaction
Redirected to http://localhost:3000/topics/6
Completed 302 Found in 11ms (ActiveRecord: 4.3ms)

编辑2：

所以我尝试了其他似乎有效的方法，但我很想知道为什么上述方法不起作用。

如果，在我的Topic#create我就这样做了：

@client = Client.find(params[:client_id])
@topic = Topic.new(params[:topic])
@client.topics << @topic

工作正常。

但是，再次......我很想知道为什么.build不适合HABTM或在这种情况下。

Answer 1

我认为问题出在params[:client_id]，可能是params[:id]。

您是否可以在if else创建操作块中添加puts语句，然后查看当您点击页面时显示的内容（创建主题）

修改

您需要在模型中包含 accepts_nested_attributes_for ，以支持动态构建嵌套对象属性。

参考this。

Answer 2

似乎我必须在我的@client对象上完成构建后显式调用save。

否则，ActiveRecord将不保存事务并在join_table中插入新记录。

如何使我的创建操作适用于嵌套和放大的操作;非嵌套资源？

2 个答案: