Rails的外鍵在嵌套形式爲零

Question

我有幾個模型（網站和服務器），通過has_many：through與eachother相關。他們也都屬於：用戶。在我的網站/新視圖中，我創建了一個新網站，並使用嵌套的form.fields_for：servers創建了一個新的服務器。一切都按預期工作，除了最終創建的服務器沒有填充user_id。我如何確保它是？

我sites_controller新創建的方法：

def new 
    @user = current_user 
    @site = @user.sites.build 
    @servers = @user.servers.all 

    # let there be one server linked 
    @site.site_servers.build 

    # @user.servers.build if @user.servers.empty? 
    @site.servers.build(:user_id => current_user.id) if @site.servers.empty? 

    respond_to do |format| 
     format.html # new.html.erb 
     format.xml { render :xml => @site } 
    end 
    end 

    def create 
    @site = current_user.sites.build(params[:site]) 

    respond_to do |format| 
     if @site.save 
     flash[:notice] = 'Site was successfully created.' 
     format.html { redirect_to(@site) } 
     format.xml { render :xml => @site, :status => :created, :location => @site } 
     else 
     format.html { render :action => "new" } 
     format.xml { render :xml => @site.errors, :status => :unprocessable_entity } 
     end 
    end 
    end 

如果您發現該註釋行，這些事情我試過，沒有工作。

型號：

class User < ActiveRecord::Base 
    acts_as_authentic 

    has_many :sites 
    has_many :servers 
end 

class Site < ActiveRecord::Base 

    belongs_to :user 

    has_many :site_servers 
    has_many :servers, :through => :site_servers 

    accepts_nested_attributes_for :site_servers, :allow_destroy => true 
    accepts_nested_attributes_for :servers, :allow_destroy => true 

    validates_presence_of :name, :on => :create, :message => "Name is required" 
end 

class Server < ActiveRecord::Base 
    attr_encrypted :password, :key => '393b79433f616f445f652a752d', :attribute => 'crypted_password' 

    belongs_to :user 

    has_many :site_servers 
    has_many :sites, :through => :site_servers 

    validates_presence_of :url, :on => :create, :message => "URL is required." 
    validates_presence_of :username, :on => :create, :message => "Username is required." 
    validates_presence_of :password, :on => :create, :message => "Password is required." 


    def name 
    username + "@" + url 
    end 

    def to_s 
    name 
    end 

end 

class SiteServer < ActiveRecord::Base 
    belongs_to :site 
    belongs_to :server 

    has_one :user, :through => :site 
end 

而且這裏是我的架構：

ActiveRecord::Schema.define(:version => 20091203045550) do 

    create_table "servers", :force => true do |t| 
    t.string "url" 
    t.string "username" 
    t.string "crypted_password" 
    t.integer "port" 
    t.integer "user_id" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    end 

    create_table "site_servers", :force => true do |t| 
    t.integer "site_id" 
    t.integer "server_id" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    end 

    create_table "sites", :force => true do |t| 
    t.string "name" 
    t.string "url" 
    t.string "path" 
    t.integer "user_id" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    end 

    create_table "users", :force => true do |t| 
    t.string "username" 
    t.string "email" 
    t.string "crypted_password" 
    t.string "password_salt" 
    t.string "persistence_token" 
    t.datetime "created_at" 
    t.datetime "updated_at" 
    end 

end 

Answer 1

你有一個隱藏字段在服務器形式USER_ID？

<%= f.hidden_field :user_id %> 

如果不是，則即使您設法正確設置值，該值也不會傳回。如果您向表單添加隱藏字段，那麼您已註釋掉的行將會起作用。

@site.servers.build(:user_id => current_user.id) if @site.servers.empty? 

其實我喜歡，設置用戶ID的創建方法更好，因爲否則你介紹的人起草了自己的表單提交，創造下其他人的用戶ID事情的可能性的想法。我不知道安全在你的應用中是否是一件大事，但我永遠不會相信從窗體發送的用戶ID。

Answer 2

我猜問題是在你的create行動。新的行動只是建立Ruby對象 - 你需要確保有在創建操作類似構建代碼：

def create 
    @site = current_user.sites.build(params[:site]) 
    @site.save 
end