如何检测用户的连接丢失或他关闭了 Nodejs socket.io 中的浏览器窗口
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how to detect that user's connection is lost or he closed the browser window in Nodejs socket.io
提问by TaLha Khan
I have a chat application on Node.js and Socket.io, user can connect and disconnect with a button...
I am having a list of online users which is perfectly managed with the help of my defined events that user trigger.
But the problem is I am unable to detect if the user has lost his connection or closed the browser window without disconnecting himself manually(by the disconnect button)...
我在 Node.js 和 Socket.io 上有一个聊天应用程序，用户可以通过一个按钮连接和断开连接......我有一个在线用户列表，在用户触发的我定义的事件的帮助下完美管理。
但问题是我无法检测到用户是否失去了连接或关闭了浏览器窗口而没有手动断开连接（通过断开按钮）...
This socket.io event is fired only when user disconnects himself not when he lost his connection.
此 socket.io 事件仅在用户断开连接时触发，而不是在失去连接时触发。
socket.on('disconnect',function(){
console.log('user disconnected'); });
I want some really good mechanism to keep an eye on users in order to update my Online users list.
我想要一些非常好的机制来关注用户以更新我的在线用户列表。
回答by Salvatorelab
And what's the difference? Closing the window, cutting the ethernet wire... it's all the same for the server: end of connection.
有什么区别？关闭窗口，切断以太网线……对于服务器来说都是一样的：连接结束。
Reading the socket.io docs: https://github.com/LearnBoost/socket.io/wiki/Exposed-events
阅读 socket.io 文档：https: //github.com/LearnBoost/socket.io/wiki/Exposed-events
socket.on('disconnect', function() {}) - the disconnect event is fired in all cases, when the client-server connection is closed. It fires on wanted, unwanted, mobile, unmobile, client and server disconnects.
socket.on('disconnect', function() {}) - 在所有情况下，当客户端-服务器连接关闭时，都会触发 disconnect 事件。它会在需要的、不需要的、移动的、不可移动的、客户端和服务器断开连接时触发。
You should not rely your button, as people can disconnect without using that button. Use the disconnect event and once a socket disconnects (a socket, not a user, cause Node just knows about sockets) you will have to find out who was the "owner" of that socket and flag him as "disconnected". Or even better, wait for a few seconds and then flag him as offline. Why? Because the disconnect event will trigger even if the user just reloads the page, or navigates to another one. So if you wait a few seconds the user will be online again.
您不应该依赖您的按钮，因为人们可以不使用该按钮就断开连接。使用 disconnect 事件，一旦套接字断开连接（套接字，而不是用户，因为 Node 只知道套接字），您将必须找出谁是该套接字的“所有者”并将他标记为“已断开连接”。或者甚至更好，等待几秒钟，然后将他标记为离线。为什么？因为即使用户只是重新加载页面或导航到另一个页面，也会触发断开连接事件。因此，如果您等待几秒钟，用户将再次在线。
I had this problem too, and I ended up creating a "watcher" that runs every X seconds and flags users as offline when they don't own any socket or when they seem to be away (no activity for a long time).
我也有这个问题，我最终创建了一个“观察者”，它每 X 秒运行一次，并在用户没有任何套接字或他们似乎不在时（很长时间没有活动）将用户标记为离线。
