socket.io - can't get it to work, having 404's on some kind of polling call

Question

I'm trying to get a server set up with socket.io, with bad results.

I am mostly following this guide, although it's somewhat out of date: http://www.williammora.com/2013/03/nodejs-tutorial-building-chatroom-with.html

The problem comes with socket.io, I'm not sure if it's client or server side. It appears to be trying to continuously poll the server, but is getting 404's back. That sounds like socket.io isn't running, but it all looks okay to me. It may also have something to do with paths and having a "public" directory, but I don't really know.

127.0.0.1 - - [Thu, 17 Jul 2014 00:51:36 GMT] "GET /socket.io/?EIO=2&transport=polling&t=1405558296120-0 HTTP/1.1" 404 73 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.76.4 (KHTML, like Gecko) Version/7.0.4 Safari/537.76.4"
127.0.0.1 - - [Thu, 17 Jul 2014 00:51:37 GMT] "GET /socket.io/?EIO=2&transport=polling&t=1405558297181-1 HTTP/1.1" 404 73 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.76.4 (KHTML, like Gecko) Version/7.0.4 Safari/537.76.4"
127.0.0.1 - - [Thu, 17 Jul 2014 00:51:39 GMT] "GET /socket.io/?EIO=2&transport=polling&t=1405558299207-2 HTTP/1.1" 404 73 "http://localhost:8080/" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_3) AppleWebKit/537.76.4 (KHTML, like Gecko) Version/7.0.4 Safari/537.76.4"

Server

var exec = require( "child_process" ).exec;
var path = require( "path" );
var morgan = require( "morgan" );
var bodyParser = require( "body-parser" );
var _ = require( "underscore" );
var express = require( "express" );
var app = express();
var http = require( "http" ).createServer( app );
var io = require( "socket.io" )( http );

app.set( "ipaddr", "127.0.0.1" );
app.set( "port", 8080 );

//support JSON, urlencoded, and multipart requests
app.use( bodyParser() );

//log the requests using morgan
app.use( morgan() );

//specify the Jade views folder
app.set( "views", __dirname + "/../views" );

//set the view engine to Jade
app.set( "view engine", "jade" );

//specify static content
app.use( express[ "static" ]( "public", __dirname + "/../public" ) ); //using map-access of static so jslint won't bitch

io.on( "connection", function( socket )
{
    console.log( "A user connected." );
});

Client

script( src="js/socket.io.js" )
var socket = io.connect( "http://localhost:8080" );

I got the client js file from: node_modules/socket.io/node_modules/socket.io-client/socket.io.js

That path doesn't match either what the tutorial I'm using says, or what socket.io says to use, so maybe that's the problem, but it looks like it's probably the correct file.

Any help here?

EDIT For additional information, here is my folder hierarchy:

Webserver/
    my_modules/
        server.js
    node_modules/
        body-parser/
        express/
        jade/
        morgan/
        socket.io/
        underscore/
    public/
        css/
        js/
            server.js
    views/
        index.jade
    index.js
    package.json

The server.js in the my_modules folder is where I start socket.io on the server side. The server.js in the js folder is the client code to connect from the website.

Answer 1

It looks like Socket.IO can't intercept requests starting with /socket.io/. This is because in your case the listener is app -- an Express handler. You have to make http be listener, so that Socket.IO will have access to request handling.

Try to replace

app.set( "ipaddr", "127.0.0.1" );
app.set( "port", 8080 );

with

http.listen(8080, "127.0.0.1");

See docs for details: http://socket.io/docs/#using-with-express-3/4

Answer 2

In my case, I created my app with the Express application generator. To solve this problem, instead of edit the app.js file on the root folder of the project, I edited the file bin/www on the line after the server is defined:

/**
 * Create HTTP server.
 */

var server = http.createServer(app);
var io = require('socket.io')(server); // Add this here

Update

I found a better way here Express Generator and Socket.io

Answer 3

Just for check that is your server or just client problem you could use this web: websocket-echo, if this client connect right to your server (the first form client is usefull if your server is online, if is on your host, cuoting from websocket.org...

Using a text editor, copy the following code and save it as websocket.html somewhere on your hard drive

Code: websocket-test

The only thing different from mine that i could observe is the io client source: <script src="/socket.io/socket.io.js"></script> on your client side.

On your server you should try this way:

var express = require('express'), 
app = express(),
http = require('http'),
server = http.createServer(app),
io = require('socket.io').listen(server),
exec = require('child_process').exec,
util = require('util');

//serve our code
app.use(express.static('public'));
app.use(express.json());
app.use(express.urlencoded());
//listening on connections

io.on('connection', function (socket) {
    console.log('client connected!'); 
}
server.listen(8080);

Note that this way works fine with this dependencies: I recommend you add this code below to your package.json file:

"dependencies": {
    "express": "3.x.x",
    "socket.io": "*",
    "util": "*"
  }

cheers!

Answer 4

Re-posting this answer here, as no other answer worked for me and this one did the trick. It took me a while to find it, so hopefully I'm saving some of you time.

import io from 'socket.io-client'

const socket = io('http://localhost:3000', {
    reconnectionDelay: 1000,
    reconnection: true,
    reconnectionAttemps: 10,
    transports: ['websocket'],
    agent: false,
    upgrade: false,
    rejectUnauthorized: false
});