Using Socket IO with Express JS - ios

Question

(Not familiar with node.)
I generated my express js app using the express-generator
so the file structure looks like this
├── app.js
├── bin
│ └── www
├── package.json
├── public
│ ├── images
│ ├── javascripts
│ └── stylesheets
│ └── style.css
├── routes
│ ├── index.js
│ └── users.js
└── views
├── error.jade
├── index.jade
└── layout.jade
I wanted to implement socket io. so on file bin/www
I added this code below server.listen(port);
server.listen(port);
/**
* Socket IO
*/
var io = require('socket.io')(server);
io.on('connection', function(socket){
console.log('a user connected');
console.log(socket.id);
socket.on('disconnect', function(){
console.log('user disconnected');
console.log(socket.id);
});
});
every time a client connect, it logs
a user connected
now I want to post an update to a specific user using their socket.id
on routes/index.js
var express = require('express');
var router = express.Router();
var io = require('socket.io');
/* GET home page. */
router.route('/')
.get(function(req, res, next)
{
res.send('Nothing to do here');
})
.post(function(req, res, next)
{
var socketid = req.param('socketid');
io.broadcast.to(id).emit('message', "Hello World");
}
);
module.exports = router;
Now Every time I post. I get an error
Cannot read property 'to' of undefined
it seems that I got a wrong io.
should I require also the server inside my index.js?
or how can I use the one io var declared in www? is this possible? just use the existing objects already

Answer 1

You are getting Cannot read property 'to' of undefined, because you have not defined io in routes\index.js file and you don't have reference to io in bin/www.
You can resolve the issue by passing the newly io object to the routes file.
e.g.
bin/www
server.listen(port);
/**
* Socket IO
*/
var io = require('socket.io')(server);
//remove same lines from app.js
var routes = require('./router/index.js')(io);
app.use('/', routes)
io.on('connection', function(socket){
console.log('a user connected');
console.log(socket.id);
socket.on('disconnect', function(){
console.log('user disconnected');
console.log(socket.id);
});
});
router/index.js
module.exports = function(io) {
var express = require('express');
var router = express.Router();
/* GET home page. */
router.route('/').get(function(req, res, next){
res.send('Nothing to do here');
}).post(function(req, res, next){
var socketid = req.param('socketid');
io.broadcast.to(id).emit('message', "Hello World");
});
return router;
}
Let me know, if it doesn't work.