Question

我通过onConnection和onDisconnect事件计算在线websockets的数量：

<DOCTYPE! html>
<html>
    <head>
        <script src="https://unpkg.com/react@16/umd/react.production.min.js"></script>
        <script src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js"></script>
    </head>
    <body>
        <div id="container"></div>
        <script type='text/jsx'>
        ReactDOM.render(
            <h1>Hello World!</h1>,
            document.getElementById('container')
        );
        </script>
    </body>
</html>

但const socketIo = require('socket.io'); var on_connect = 0; var on_disconnect = 0; var port = 6001; var io = socketIo(port, { pingTimeout: 5000, pingInterval: 10000 }); //I have only one NameSpace and root NS is not used var ns1 = io.of('ns1'); ns1 .on('connection', function (socket) { on_connect += 1; socket.on('disconnect', function (reason) { on_disconnect += 1; }); }); ... var online = on_connect - on_disconnect; ...值不等于online值。

随着时间的推移，io.engine.clientsCount值和online值之间的差异正在增长。

为什么会这样？

需要做些什么来解决这个问题？

Answer 1

on_connect和on_disconnect变量是回调事件中的更新，而不会重新计算在线变量。因此，每当其他变量发生变化时，您将需要重新计算在线变量。

Answer 2

仅使用一个变量来计算连接可能更容易。在连接时递增它，并在断开时递减它。这就是我如何跟踪连接数量。然后，每次需要它时都不需要计算它。

此外，声明var online = on_connect - on_disconnect;正在之前发生的行也会被修改...这是@gvmani试图告诉你的内容。

以下是某些我正在做的事情的一个例子。下面的代码设置为监听连接＆amp;断开并保持当前连接的计数。我应该注意到我没有使用像OP那样的命名空间，但计数部分是重要的。我还要注意，我在connCount > 0函数中使用send()。在我的应用程序中用于向所有连接的客户端广播。

/* ******************************************************************** */ // initialize the server const http = require('http'); const server = http.createServer(); // Socket.io listens to our server const io = require('socket.io').listen(server); // Count connections as they occur, decrement when a client disconnects. // If the counter is zero then we won't send anything over the socket. var connCount = 0; // A client has connected, io.on('connection', function(socket) { // Increment the connection counter connCount += 1; // log the new connection for debugging purposes. console.log(`on connect - ${socket.id} ${connCount}`); // The client that initiated the connection has disconnected. socket.on('disconnect', function () { connCount -= 1; console.log(`on disconnect - ${socket.id} ${connCount}`); }); }); // Start listening... server.listen(3000); // Send something to all connected clients (a broadcast) the // 'channel' will indicate the destination within the client // and 'data' becomes the payload. function send(channel, data) { console.log(`send() - channel = ${channel} payload = ${JSON.stringify(data)}`); if(connCount > 0) io.emit(channel, {payload: data}); else console.log('send() - no connections'); };

socket.io：clientsCount以及连接和断开连接事件

2 个答案: