Question

I am trying encapsule a socket.io instance in a module. I did this but it looks a bit messy because i have to inject some dependencies for authentication of the socket transport from express / passport.

My problem is i want to access the socket instance outside of the module like socket.on("newDevice", function (data) {});

The socket instance which i get by the connection event is inside the function and it even may not exist on creation because no connection is established. This simply looks kind of wrong to me. I dont want to inject more and more depencies just because i need them inside of the function scope.

I thought about doing the sio.on('connection', function(socket) {}); outside of the module. And maybe i could do it twice, first inside of the module and then outside but i would create two listeners i guess.

Is there any good practice or pattern how to do this properly?

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

var socket = function (server, sessionStore, cookieParser, authentication)  {

    var sio = io.listen(server);

    // Configure socket.io
    sio.configure(function () {

        // Authorize the socket.io request
        sio.set('authorization', function (data, accept) {
                    // Authorization is done here
        });

    });

    sio.on('connection', function(socket) {

    var lastActionTime = new Date();

    // Get the userId from the session
    var session   = socket.handshake.session;
    var userId    = session.passport.user;
    var sessionID = socket.handshake.sessionID;

    var userdata = null;

    // Deserialize user by the userId
    authentication.deserializeUser(userId, function(err, user) {
              // get the userdata
    });


    socket.on('disconnect', function() {

    });

    socket.on('brightnessChange', function(data) {
        // TODO Do something here device control

        // Broadcast to other devices
        this.broadcast.emit('brightnessChange', data);
    });

}); 


    return sio;
};

module.exports = socket;

Answer 1

I would suggest, the below, flexibility and scales well. I’ve tried both ways and resulted in using multiple connection events.

I thought about doing the sio.on(‘connection’, function(socket) {}); outside of the module. And maybe i could do it twice, first inside of the module and then outside but i would create
two listeners i guess.