Node.js：require() 和传递变量

Question

Started a project with npm which created a certain file structure:

www <-- require() calls app.js; instantiates server

app.js <-- instantiates var app = express(); and has module.exports = app;

Now, I'd like to use sockets.io. In my 'www' file, here is a code snippet:

var app = require('../app'); ... var server = http.createServer(app);

And I'd like to put all of my server-side socket listeners in app.js, but the following code:

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

requires server as an input. How do I make the server I instantiated in 'www' accessible in 'app.js'?

Answer 1

It seems a little strange. But if you insist on such a structure than you can export an object from www that will have app as it's property and a method that binds socket listeners an receives app object as a param.

module.exports = {
    app:  app,
    bindSocketListeners: function(server, io) {
        io.listen(server);
        return io; 
    } 
};

And call it:

var appObj = require('../app');
var io = require('socket.io');
var app = appObj.app;
var server = http.createServer(app);
io  = appObj.bindSocketListeners(server, io)