socket.io 服务器在注册客户端断开连接时非常延迟 [英] socket.io server very delayed in registering client disconnects

问题描述

我有一个使用 xhr 作为唯一传输的 socket.io 连接.当我在浏览器中加载应用程序(在 chrome 和 ff 中测试)时，套接字连接并且一切正常，直到我离开页面.如果我重新加载浏览器，我可以看到客户端发送了 'disconnect' 事件，但是服务器断开连接事件在很长一段时间内都不会触发(大概是在客户端心跳超时时).这是一个问题，因为当客户端断开连接时，我在服务器中做了一些清理工作.如果客户端重新加载，我会在断开连接之前收到多个连接事件.我也尝试在窗口的beforeunload"事件中手动从客户端发出断开连接消息，但无济于事.有什么想法吗?

I have a socket.io connection using xhr as its only transport. When I load up the app in the browser (tested in chrome and ff), the socket connects and everything works well until I navigate away from the page. If I reload the browser, I can see the 'disconnect' event get sent out by the client, but the server disconnect event doesn't fire for a very long time (presumably when the client heartbeat times out). This is a problem because I do some cleanup work in the server when the client disconnects. If the client reloads, I get multiple connection events before disconnect is fired. I've tried manually emitting a disconnect message from the client in the window's 'beforeunload' event as well, but to no avail. Any ideas?

我调试了 socket.io 服务器，我可以确认 Manager.prototype.onClientDisconnect 仅因关闭超时"原因而受到命中.

I debugged the socket.io server, and I can confirm that Manager.prototype.onClientDisconnect is only getting hit for "close timeout" reasons.

推荐答案

经过一些调试，我注意到 socket.io Manager 对象中有如下配置:

After some more debugging, I noticed the following configuration in the socket.io Manager object:

blacklist : ['disconnect']

这会导致 namespace.js 的这个分支不处理事件:

That causes this branch from namespace.js to not process the event:

case 'event':
  // check if the emitted event is not blacklisted
  if (-~manager.get('blacklist').indexOf(packet.name)) {
    this.log.debug('ignoring blacklisted event `' + packet.name + '`');
  } else {
    var params = [packet.name].concat(packet.args);

    if (dataAck) {
      params.push(ack);
    }

    socket.$emit.apply(socket, params);
}

此拉取请求中详细说明了更改https://github.com/LearnBoost/socket.io/pull/569.我明白为什么 XHR 需要这样做，因为任何人都可以发送带有随机会话 ID 的 HTTP 请求，试图断开其他用户与服务器的连接.

The change is detailed in this pull request https://github.com/LearnBoost/socket.io/pull/569. I understand why this is in place for XHR, since anyone could send an HTTP request with random session IDs trying to disconnect other users from the server.

我打算做的是检查服务器中现有会话 ID 的每个新连接，并确保在继续连接逻辑之前运行我的断开连接逻辑.

What I plan to do instead is to check each new connection for an existing session id in the server, and make sure to run my disconnect logic before continuing with the connection logic.

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