Duplicates when I use socket.io in express.js route files

Question

I have a problem with Node.JS/Socket.IO/Express.JS and i didn't find any solution.

I use:

"express": "~4.10.6"
"socket.io": "1.2.1"

on Ubuntu Linux

My problem is that when I run the server and access localhost:3000/chat at the first run all works great but after a refresh/2/3/4 the messages inserted in chat duplicates. For one refresh, i have to identical message on one submit. For two refreshes, I have 3 identical message and so on. This behaviour began when i put the socket functionality in express.js routes folder.

P.S. I'm new to node.js/socket.io/express.js

app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index');
var users = require('./routes/users');
var chat = require('./routes/chat');

var app = express();

// Socket IO Things

var server = require('http').createServer(app);
var io = require('socket.io').listen(server);

// END - Socket IO Things

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/users', users);
app.use('/chat', chat.random_function(io));



// catch 404 and forward to error handler
app.use(function(req, res, next) {
    var err = new Error('Not Found');
    err.status = 404;
    next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
    app.use(function(err, req, res, next) {
        res.status(err.status || 500);
        res.render('error', {
            message: err.message,
            error: err
        });
    });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
        message: err.message,
        error: {}
    });
});


 module.exports = app;


server.listen('3000');

/routes/chat.js

var express = require('express');
var router = express.Router();


/* GET home page. */
router.get('/', function(req, res) {
    res.sendFile(__dirname + '/index.html');
});

module.exports = {

    router: router,
    random_function: function(io) {

        return function(req, res){

            res.sendFile(__dirname + '/index.html');

            io.sockets.on('connection', function (socket) {

                socket.on('send message', function (data) {

                    io.sockets.emit('new message', data);

                });

            });
        }
    }


};

Client side sockets (routes/index.html)

<html>
<head>
    <title>Chat with socket.io and node.js</title>
    <style>
        #chat {
            height: 500px;
        }
    </style>
</head>

<body>
<div id="chat"></div>
<form id="chat-message" action="">
    <input size="35" id="message"></input>
    <input type="submit"></input>
</form>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="/socket.io/socket.io.js"></script>

<script>

        var socket = io.connect();
        var $messageForm = $('#chat-message');
        var $messageBox = $('#message');
        var $chat = $('#chat');

        $messageForm.submit(function(e){

            e.preventDefault();
            socket.emit('send message', $messageBox.val());
            $messageBox.val("");

        });

        socket.on('new message', function(data){

            $chat.append(data + "<br>");

        });


</script>

</body>

</html>

How can I handle this problem? Thanks in advance! I also checked the debugger and on server come 1/2/3/4/5 different packages each time.

meeDamian meeDamian · Accepted Answer · 2015-01-17T21:05:22

You're creating & attaching new connection listener on each /chat request. Try moving it outside of random_function and perhaps creating separate socket instance for each connection/client.

(Edit) code added:

Try this (should work, but I didn't test it)

app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var routes = require('./routes/index');
var users = require('./routes/users');
var chat = require('./routes/chat');

var app = express();

// Socket IO Things

var server = require('http').createServer(app);
var io = require('socket.io').listen(server);
io.sockets.on('connection', function (socket) {

    socket.on('send message', function (data) {

        io.sockets.emit('new message', data);

    });

});

// END - Socket IO Things

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/users', users);
app.use('/chat', chat.random_function);

routes/chat.js

var express = require('express');
var router = express.Router();


/* GET home page. */
router.get('/', function(req, res) {
    res.sendFile(__dirname + '/index.html');
});

module.exports = {

    router: router,
    random_function: function(req, res){
          res.sendFile(__dirname + '/index.html');
    }

};

Duplicates when I use socket.io in express.js route files

1 Answers

app.js

routes/chat.js