ActionCable - 如何显示已连接用户的数量?

问题描述

我正在尝试使用 Action Cable 创建一个简单的类似聊天的应用程序(规划扑克应用程序).我对术语、文件层次结构以及回调的工作方式有点困惑.

I'm trying to create a simple chat-like application (planning poker app) with Action Cable. I'm a little bit confused by the terminology, files hierarchy and how the callbacks work.

这是创建用户会话的操作:

This is the action that creates user session:

class SessionsController < ApplicationController
  def create
    cookies.signed[:username] = params[:session][:username]
    redirect_to votes_path
  end
end

然后用户可以发布应该向所有人广播的投票:

A user can then post a vote that should be broadcasted to everyone:

class VotesController < ApplicationController
  def create
    ActionCable.server.broadcast 'poker',
                                 vote: params[:vote][:body],
                                 username: cookies.signed[:username]
    head :ok
  end
end

到目前为止，一切对我来说都很清楚并且工作正常.问题是 - 如何显示已连接用户的数量?当用户(消费者?)连接时，JS 中是否会触发回调?我想要的是当我以隐身模式在 3 个不同的浏览器中打开 3 个标签时，我想显示3".当新用户连接时，我希望数字递增.如果任何用户断开连接，则该数字应递减.

Up to this point everything is clear for me and works fine. The problem is - how do I display the number of connected users? Is there a callback that fires in JS when a user (consumer?) connects? What I want is when I open 3 tabs in 3 different browsers in incognito mode I would like to display "3". When a new user connects, I would like the number to increment. If any user disconnects, the number should decrement.

我的PokerChannel:

class PokerChannel < ApplicationCable::Channel
  def subscribed
    stream_from 'poker'
  end
end

app/assets/javascripts/poker.coffee:

App.poker = App.cable.subscriptions.create 'PokerChannel',

  received: (data) ->
    $('#votes').append @renderMessage(data)

  renderMessage: (data) ->
    "<p><b>[#{data.username}]:</b> #{data.vote}</p>"

推荐答案

好像是一种方式使用

ActionCable.server.connections.length

(见评论中的注意事项)

(See caveats in the comments)

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