嵌套资源

Question

我正在尝试将消息控制器嵌套到通道控制器中。 出现错误“无法找到没有 id 的频道”

 class MessagesController < ApplicationController

  def index
    @channel = Channel.find(params[:channel_id])
    @messages = @channel.messages
  end

  def new
    @channel = Channel.find(params[:channel_id])
    @message = @channel.messages.build
  end

  def create
    @channel = Channel.find(params[:channel_id])
    @message = @channel.messages.build(params[:message])
    if @message.save
      flash[:notice] = "Successfully created message."
      redirect_to channel_url(@message.channel_id)
    else
      render :action => 'new'
    end
  end

  def edit
    @message = Message.find(params[:id])
  end

  def update
    @message = Message.find(params[:id])
    if @message.update_attributes(params[:message])
      flash[:notice] = "Successfully updated message."
      redirect_to channel_url(@message.channel_id)
    else
      render :action => 'edit'
    end
  end

  def destroy
    @message = Message.find(params[:id])
    @message.destroy
    flash[:notice] = "Successfully destroyed message."
    redirect_to channel_url(@message.channel_id)
  end
end

Channelscontrollerroutes.rb

class ChannelsController < ApplicationController

  def index
    @channels = Channel.find(:all)
  end

  def show
    @channel = Channel.find(params[:id])
    @message = Message.new(:channel => @channel)
  end

  def new
    @channel = Channel.new
  end

  def create
    @channel = Channel.new(params[:channel])
    if @channel.save
      flash[:notice] = "Successfully created channel."
      redirect_to @channel
    else
      render :action => 'new'
    end
  end

  def edit
    @channel = Channel.find(params[:id])
  end

  def update
    @channel = Channel.find(params[:id])
    if @channel.update_attributes(params[:channel])
      flash[:notice] = "Successfully updated channel."
      redirect_to @channel
    else
      render :action => 'edit'
    end
  end

  def destroy
    @channel = Channel.find(params[:id])
    @channel.destroy
    flash[:notice] = "Successfully destroyed channel."
    redirect_to channels_url
  end
end

但是，当我转到消息视图时，

   SeniorProject::Application.routes.draw do

  resources :users
  resources :channels, :shallow => true do |channels|
    channels.resources :messages
  end

  root :channels

  resources :users, :user_sessions

  match 'login' => 'user_sessions#new', :as => :login
  match 'logout' => 'user_sessions#destroy', :as => :logout
  match ':controller(/:action(/:id(.:format)))'

end

Answer 1

这里发生的事情是，这一行：

@channel = Channel.find(params[:channel_id])

正在失败，因为 params 哈希中没有定义的channel_id。我看到你正在使用浅层路由，这意味着你的uri可能看起来像这样：

/messages

并且你需要它看起来像这样：

/channels/1/messages

尝试将你的url更改为：

channel_messages_url(@channel)

而不是

messages_url

这是一个猜测顺便说一句，这可能是因为你的方式已经定义了 routes.rb，这看起来有点奇怪，因为您定义了两次消息路由，一次使用 has_many，另一次作为适当的资源。你可能想要这样的东西：

# assuming you need shallow routes
resources :channels, :shallow => true do |channels|
  channels.resources :messages
end