title: learn enough action cable tutorial not working
body: <p>I am working on Hartl's tutorial Learn Enough Action Cable, and I'm stuck on section 4.1. I copied and pasted the code from the tutorial just to be sure, and the pop up window with data.content still wont come up.</p>
  
  <p>Messages Controller:</p>
  
  <pre><code>.
  .
  def create
     message = current_user.messages.build(message_params)
     if message.save
        ActionCable.server.broadcast 'room_channel',
                                content:  message.content,
                                username: message.user.username
    end
  end
  </code></pre>
  
  <p>room_channel.rb:</p>
  
  <pre><code>    class RoomChannel &lt; ApplicationCable::Channel
         def subscribed
         stream_from "room_channel"
      end
  
      def unsubscribed
      end
   end
  </code></pre>
  
  <p>routes.rb:</p>
  
  <pre><code>Rails.application.routes.draw do
  root 'messages#index'
  resources :users
  resources :messages
  get    '/login',   to: 'sessions#new'
  post   '/login',   to: 'sessions#create'
  delete '/logout',  to: 'sessions#destroy'
  
  mount ActionCable.server, at: '/cable'
  end
  </code></pre>
  
  <p>room.coffee:</p>
  
  <pre><code>App.room = App.cable.subscriptions.create "RoomChannel",
  connected: -&gt;
  # Called when the subscription is ready for use on the server
  
  disconnected: -&gt;
  # Called when the subscription has been terminated by the server
  
  received: (data) -&gt;
  alert(data.content)
  </code></pre>
  
  <p>Every other part of the tutorial worked fine with pop-up windows coming up for javascript alerts. In my server logs it says:</p>
  
  <pre><code>Started GET "/cable" for 127.0.0.1 at 2017-03-26 13:59:12 -0400
  Started GET "/cable/" [WebSocket] for 127.0.0.1 at 2017-03-26 13:59:12 -0400
  Successfully upgraded to WebSocket (REQUEST_METHOD: GET,HTTP_CONNECTION:     keep-alive, Upgrade, HTTP_UPGRADE: websocket)
  RoomChannel is transmitting the subscription confirmation
  RoomChannel is streaming from room_channel
  Finished "/cable/" [WebSocket] for 127.0.0.1 at 2017-03-26 14:06:26 -0400
  RoomChannel stopped streaming from room_channel
  Started GET "/messages" for 127.0.0.1 at 2017-03-26 14:06:26 -0400
  Processing by MessagesController#index as HTML
  User Load (0.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ?   LIMIT ?  [["id", 1], ["LIMIT", 1]]
  Message Load (0.2ms)  SELECT  "messages".* FROM "messages" ORDER BY        "messages"."created_at" DESC LIMIT ?  [["LIMIT", 50]]
   Rendering messages/index.html.erb within layouts/application
  Rendered messages/_messages.html.erb (0.6ms)
  Rendered messages/_message_form.html.erb (2.0ms)
  Rendered messages/index.html.erb within layouts/application (4.5ms)
  Rendered layouts/_logo.html.erb (0.4ms)
  Rendered layouts/_header.html.erb (2.0ms)
  Completed 200 OK in 71ms (Views: 36.4ms | ActiveRecord: 1.5ms)
  </code></pre>