如何讓我的創建操作爲嵌套和非嵌套資源工作？

Question

所以我有兩種型號Topic,Client。客戶has_and_belongs_to_many :topics和主題has_and_belongs_to_many :clients。

基本上，我希望發生的是什麼？當有人去我Topic#index，這取決於他們是如何到達那裏（即無論是通過client/:id/topics或只是/topics），我想要的行爲創造&新是不同的。即在/topics，它只是創建一個話題。在client/:id/topics它創建一個主題並將其分配給該客戶端。

我的路線是這樣的：

resources :topics 
    resources :clients do 
    resources :topics 
    end 

我的主題控制器看起來是這樣的：

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views/topics/_form.html.erb看起來是這樣的：

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

然而，當我執行來自client/:id/topics的行爲這是日誌的樣子：

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) 

這看起來不錯......一切似乎都是爲了這裏。但正是在這件事似乎不工作POST：

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) 

你會發現沒有新的話題給客戶端的分配。

我錯過了什麼？

謝謝！

編輯1

新增把調試語句我創建行動，這是我後，執行POST操作的結果 - 這表明，越來越的params[:client_id]並不僅僅是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) 

編輯2：

所以，我想別的事情，似乎工作，但我會愛知道爲什麼上述不起作用。

如果在我的Topic#create我只是這樣做：

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

它工作正常。

但是，再次...我想知道爲什麼.build不適合HABTM或在這種情況下。

Answer 1

我覺得問題是在params[:client_id]它可能是params[:id]。

你可以把puts聲明創建行動的你如果else塊，然後看看哪一個被顯示出來，當你打的頁面（創建一個話題）

編輯

您需要在您的模型中包含accep_nested_attributes_for以支持動態構建嵌套對象屬性。

參考this。

Answer 2

看來我必須顯式調用保存的版本是我@client對象上完成之後。

否則，ActiveRecord的將不保存事務並插在join_table的新紀錄。