Sharing socket.io for other modules gives an empty object

Question

I am trying to pass a socket.io socket socket.io to different node.js modules, although I fail and get an empty object with

 Cannot call method 'on' of undefined 

My code is:

app.js

 var express = require('express') , app = express(); var server = require('http').createServer(app) , io = require('socket.io').listen(server) var routes = require('./routes') , path = require('path') , rss = require('./routes/rss') // ... exports.io = io; 

<strong> routes /rss.js

 io = require(__dirname + '/../app'); console.log(io); io.sockets.on('connection', function( console.log("Connection on socket.io on socket"); // .. do stuff }); 

What I get from this:

 $ node app.js info - socket.io started {} /home/XXX/programming/nodejs/node-express-aws/routes/rss.js:10 io.sockets.on('connection', function(socket){ ^ TypeError: Cannot call method 'on' of undefined at Object.<anonymous> (/home/XXX/programming/nodejs/node-express-aws/routes/rss.js:10:12) at Module._compile (module.js:456:26) at Object.Module._extensions..js (module.js:474:10) at Module.load (module.js:356:32) at Function.Module._load (module.js:312:12) at Module.require (module.js:364:17) at require (module.js:380:17) at Object.<anonymous> (/home/XXX/programming/nodejs/node-express-aws/app.js:9:10) at Module._compile (module.js:456:26) at Object.Module._extensions..js (module.js:474:10) 

Although I tried, and I can do the same with socket.io only one file (app.js)

 var express = require('express') , app = express(); var server = require('http').createServer(app) , io = require('socket.io').listen(server) var routes = require('./routes') , path = require('path') , rss = require('./routes/rss') // ... io.sockets.on('connection', function(socket){ logger.debug("Connection on socket.io on socket"); socket.emit('news', {will: 'be recived'}); }); 

Answer 1

Since in app.js you have:

 exports.io = io; 

then you will need to use it like this:

 var app = require('../app'); var io = app.io; 

That is, you said that you connected a property called io to the module, so when you need this module, you get an object that has the io property.

You can also do

 module.exports = io; 

and then leave rss.js way you have it now.

---

All that said, if you use app.js with Node, you will often see an io object embedded in other modules (instead of another); eg:

app.js

 var express = require('express') , app = express(); var server = require('http').createServer(app) , io = require('socket.io').listen(server) var routes = require('./routes') , path = require('path') , rss = require('./routes/rss') // ... rss(io); // pass `io` into the `routes` module, // which we define later to be a function // that accepts a Socket.IO object 

routes/rss.js

 module.exports = function(io) { io.sockets.on('connection', function( console.log("Connection on socket.io on socket"); // .. do stuff }); } 

Answer 2

I pass the io object to the connection handler.

 var socket = require('./routes/socket.js'); io.sockets.on('connection', function(sock){ socket.stuff(sock, io); }); 

./routes/socket.js should contain the following:

 var socket = module.exports = {}; socket.stuff = function(sock, io){ //handle all events here };