How to resolve a Socket.io 404 (Not Found) error?

Question

I am using Socket.io with Express. In my project I have a login page and a home page. When I do successful login, I navigate to localhost:3000/home where I get this error:

GET http://localhost:3000/socket.io/?EIO=3&transport=polling&t=1418187395022-0 404 (Not Found) 

I did not do any modification in my app.js (project created by express ).

index.js:

var express = require('express'); var router = express.Router(); var http = require('http'); var fs = require('fs'); var io = require('socket.io')(http); /* GET home page. */ router.get('/', function(req, res) {   res.render('index', { title: 'Express' }); });  router.get('/home', function(req, res) {   res.render('home', { title: 'Express' }); });  io.on('connection', function(socket){     console.log("User Connected");   socket.on('chat message', function(msg){     io.emit('chat message', msg);     console.log("Message");   });    socket.on('disconnect', function(msg){     console.log("User DisConnected");   });  });  router.post('/authenticate', function(req, res) {     fs.readFile("./public/Verification/Users.json", "utf8", function (err, data) {         if (err)              console.log(err);         else{             var result = JSON.parse(data);             for(var i=0;i<result.Users.length;i++){                 if(req.body.username == result.Users[i].username && req.body.password ==     result.Users[i].password){                     console.log("Success!!!!!!!!!!!!!!");                     res.location("home");                     res.redirect("home");                 }             }         }         }); });  module.exports = router; 

In my layout.jade I defined Socket.io like this:

script(src='https://cdn.socket.io/socket.io-1.2.0.js') 

Answer 1

If you're running Express 4, it appears to me like you're missing the lines of code:

var app = express(); var server = app.listen(3000); 

That will start your web server and set it to port 3000. See the bone simple Express 4 app here: http://expressjs.com/4x/api.html

And, then to start up socket.io, you would add:

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

And, there is no need for this line:

var http = require('http');