node.js - Incorrect connections number -

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i wrote simple script retrieve list of connected users.

var app, io, server;  app = require("express")(); server = require("http").createserver(app); io = require("socket.io").listen(server);  server.listen(1339);  app.get("/", function(req, res) {   res.sendfile(__dirname + "/index.html"); });  console.log('init', io.sockets.manager.server.connections);  io.sockets.on("connection", function(socket) {   console.log('connect: ', io.sockets.manager.server.connections);   socket.on("disconnect", function(data) {     console.log('disconnect: ', io.sockets.manager.server.connections);   }); });

and html:

<!doctype html> <html> <head>     <meta charset="utf-8">     <title>title</title> </head> <body>     <script src="/socket.io/socket.io.js"></script>     <script>         var socket = io.connect('http://localhost:1339');     </script> </body> </html>

when run app 0 on init, open page in browser gives me 4 connections instead of 1. connections property deprecated. use getconnections() method warning. using node in v0.10.15 , socket.io in v0.9.16.

you'll need obtain number of clients different location:

 io.sockets.clients().length

however, when read this active github issue, might want avoid operation can cause additional memory leak (beyond what's happening sockets).

here's complete working example:

var app = require('express')(); var server = require("http").createserver(app); var io = require('socket.io').listen(server);  server.listen(1339);  app.get('/', function(req, res) {     return res.sendfile(__dirname + "/index.html"); });  /*     obtain number of connected clients         io.sockets.clients().length              */  console.log("init", io.sockets.clients().length );  io.sockets.on("connection", function(socket) {     console.log("connect:" + io.sockets.clients().length);     socket.on("disconnect", function(data){         console.log("disconnect: ", io.sockets.clients().length);     }); });

the disconnect event happens before client has been removed, count 1 higher total number of clients (depending on how @ it).

also, had on event handlers returning values reason, removed that.

instead of using function, might have better luck simple counter:

var clientsconnected = 0;  console.log("init", io.sockets.clients().length );  io.sockets.on("connection", function(socket) {     console.log("connect:" + ++clientsconnected);     socket.on("disconnect", function(data){         console.log("disconnect: ", --clientsconnected);     }); });

some have apparently reported number of disconnects can exceed number of connections, may want prevent counter dropping below zero.

connected 2 clients (and disconnected one):

info: socket.io started init 0 debug: served static content /socket.io.js debug: client authorized info: handshake authorized ejcvvsr60fmrzhvpq6ro debug: setting request /socket.io/1/websocket/ejcvvsr60fmrzhvpq6ro debug: set heartbeat interval client ejcvvsr60fmrzhvpq6ro debug: client authorized  debug: websocket writing 1:: connect:1 debug: served static content /socket.io.js debug: client authorized info: handshake authorized 28luudts3ktcphd0q6rp debug: setting request /socket.io/1/websocket/28luudts3ktcphd0q6rp debug: set heartbeat interval client 28luudts3ktcphd0q6rp debug: client authorized  debug: websocket writing 1:: connect:2 info: transport end (socket end) debug: set close timeout client 28luudts3ktcphd0q6rp debug: cleared close timeout client 28luudts3ktcphd0q6rp debug: cleared heartbeat interval client 28luudts3ktcphd0q6rp disconnect:  2 debug: discarding transport info: transport end (socket end) debug: set close timeout client ejcvvsr60fmrzhvpq6ro debug: cleared close timeout client ejcvvsr60fmrzhvpq6ro debug: cleared heartbeat interval client ejcvvsr60fmrzhvpq6ro disconnect:  1 debug: discarding transport

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