TypeError:未定义App.cable

Question

我在我的机器上运行ActionCable时遇到问题。

在assets/javascripts/channels中我有两个文件：

index.coffee

#= require action_cable
#= require_self
#= require_tree .

@App = {}
App.cable = ActionCable.createConsumer()

和question.coffee

App.question = App.cable.subscriptions.create "QuestionChannel",
  connected: ->
    # Called when the subscription is ready for use on the server

  disconnected: ->
    # Called when the subscription has been terminated by the server

  received: (data) ->
    # Called when there's incoming data on the websocket for this channel

  follow: ->
    @perform 'follow'

  unfollow: ->
    @perform 'unfollow'

我的application.js文件如下所示：

// This is a manifest file that'll be compiled into application.js, which will include all the files
// listed below.
//
// Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
// or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
//
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// compiled file.
//
// Read Sprockets README (https://github.com/sstephenson/sprockets#sprockets-directives) for details
// about supported directives.
//
//= require jquery
//= require jquery_ujs
//= require bootstrap-sprockets
//= require icheck
//= require homer/scripts
//= require Chart
//= require excanvas
//= require channels
//= require_tree .

当我启动cable服务器和rails服务器并访问firefox控制台中的localhost:3000时，我看到两个错误：

SyntaxError: An invalid or illegal string was specified


this.webSocket = new WebSocket(this.consumer.url);

和

TypeError: App.cable is undefined


App.question = App.cable.subscriptions.create("QuestionChannel", {

我使用的是Rails5beta3，我该怎么解决这个问题呢？

Answer 1

ActionCable.createConsumer需要一个参数-操作电缆服务器的地址。

@App = {}
App.cable = ActionCable.createConsumer("ws://cable.example.com")

如果您缺少此参数，则this.customer.url是未定义的。

Answer 2

确保你有

<%= action_cable_meta_tag %>

在您的应用程序布局中的某个位置。

默认情况下，Rails生成并负责将电缆URL提供给Action cable，这样您就不必将其传递给

ActionCable.createConsumer()

。

Answer 3

我也有同样的问题。我把我的服务器换成了puma，真是太棒了！

您可以通过添加gem 'puma'并运行bundle进行更改。

另外，确保在development.rb文件中使用config.action_cable.url = "ws://localhost:3000/cable"。祝好运