websocket works with http module but not with express (node.js)

Question

I'm trying to make websokects work with node.js using express and websocket modules.
The funny thing is that if I use the http module to create the server they work as expected, I receive status 101.
But if I use the express module to create the server it'll throw an error:

WebSocket connection to 'ws://localhost:2345/' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

Here's the code

// using http module (works)
var WebSocketServer = require("websocket").server;
var http = require("http");

var app = http.createServer(function(request, response) {
    response.writeHeader(200, {'Content-Type':'text/html'});

    response.end(""+
    "<!DOCTYPE html>"+
    "<html>"+
        "<head>"+
            "<script>"+
                "var ws = new WebSocket('ws://localhost:2345/');"+
                "ws.onmessage = function(event) { "+
                "var span = document.createElement('span');"+
                "span.innerHTML = event.data;"+
                "document.body.appendChild(span);"+
                "}"+
            "</script>"+
        "</head>"+
        "<body>"+
            "<span>Messages: </span>"+
        "</body>"+
    "</html>"
    );
});

app.listen(2345);

wsServer = new WebSocketServer({'httpServer':app});

wsServer.on("request", function(request) {
    var connection = request.accept(null, request.origin);
    console.log("Connection ACCEPTED\n");

    connection.on("message", function(message)
    {
        if(message.type == 'utf8')
        {
            console.log("Received Message: %s", message.utf8Data);
            connection.sendUTF(message.utf8Data);
        }
    })

    connection.on("close", function(reasonCode, description)
    {
        console.log("Connection lost\n");
    })
})

and the non working part

// using express module (get error)
var WebSocketServer = require("websocket").server;
var app = require('express')();

var app.get('/', function(request, response) {
    response.writeHeader(200, {'Content-Type':'text/html'});

    response.end(""+
    "<!DOCTYPE html>"+
    "<html>"+
        "<head>"+
            "<script>"+
                "var ws = new WebSocket('ws://localhost:2345/');"+
                "ws.onmessage = function(event) { "+
                "var span = document.createElement('span');"+
                "span.innerHTML = event.data;"+
                "document.body.appendChild(span);"+
                "}"+
            "</script>"+
        "</head>"+
        "<body>"+
            "<span>Messages: </span>"+
        "</body>"+
    "</html>"
    );
});

app.listen(2345);

wsServer = new WebSocketServer({'httpServer':app});

wsServer.on("request", function(request) {
    var connection = request.accept(null, request.origin);
    console.log("Connection ACCEPTED\n");

    connection.on("message", function(message)
    {
        if(message.type == 'utf8')
        {
            console.log("Received Message: %s", message.utf8Data);
            connection.sendUTF(message.utf8Data);
        }
    })

    connection.on("close", function(reasonCode, description)
    {
        console.log("Connection lost\n");
    })
})

What could be wrong there? How to solve this issue?

jfriend00 · Accepted Answer · 2015-02-15 17:49:22Z

2

The app in Express is not the httpServer, so if the WebSocketServer doesn't explicitly know about Express and how to get the server from it, then you probably need to give it the actual httpServer object rather than the Express object which you can do by changing this:

app.listen(2345);
wsServer = new WebSocketServer({'httpServer':app});

to this:

var server = app.listen(2345);
var wsServer = new WebSocketServer({'httpServer': server});

answered Feb 15, 2015 at 17:49

jfriend00

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