javascript - Socket io connects to multiple sockets on reconnect -

i have 1 application have implemented notification using using node js , socket io , redis.

there have configured publisher , subscriber in node js. using socket io can show messages on client realtime.

my design 1 publisher publishes many channels , every user listening own channel.

i publishes channel1 , channel2 , users listening channels only, getting respective messages 1 time.

till worked fine, smoothly.

but here problem starts. when internet goes offline tries reconnect , when again establishes connection, on every single publish starts subscribe twice , result of messeges showing twice.

my code on server subscriber side

io.sockets.on('connection', function (socket) {     var channelname = "channel"+socket.handshake.query.ch;     console.log("=======================================================================");     console.log("connected client - ["+socket.id+"] ["+channelname+"]");     console.log("transport method - ["+io.transports[socket.id].name+"]");     console.log("=======================================================================");      try{         var client = redis.createclient();         client.on("connect",function(){             client.subscribe(channelname)?console.log("channel subscribed {"+channelname+"}"):console.log("not subscribed {"+channelname+"}");             client.on("message", function(channel,message){             console.log("=======================================================================");             console.log("got message ["+message+"] in ["+channel+"]");             socket.emit("notification"+channel, { msg: message });             console.log("=======================================================================");             });         });     }catch(e){         console.log("redis server not running !!");     }      socket.on('disconnect', function(){     console.log("disconnected client !!");     }); }); 

on client side code this

<script src="localhost:3000/socket.io/socket.io.js"></script> <script>      // 1 client ch=1 , ch=2     var socket = io.connect("localhost:3000",{ query: "ch=1", "try multiple transports":false});     socket.on('connect', function(data){         $("div#status").html("<div class='connected'></div><span>connected</span>");     });      // 1 client event notificationchannel1 , client event notificationchannel2     socket.on('notificationchannel1',function(data){         $("div#notification-div").append(data.msg);     });     socket.on('connecting', function(data){         $("div#status").html("<div class='connecting'></div><span>connecting</span>");     });     socket.on('disconnect', function(data){         $("div#status").html("<div class='disconnected'></div><span>disconnected</span>");     });     socket.on('reconnecting', function(data){         $("div#status").html("<div class='reconnecting'></div><span>reconnecting...</span>");     });           </script> 

please suggest me things missing.