Challenge 5 Solution

In notebook:
FrontEndMasters Building Web Apps with Node.js
Created at:
2015-10-12
Updated:
2015-10-12
Tags:
backend Node JS JavaScript
Video Course on Building Web Applications with Node.jsSometimes your app needs to be on a visible public address

explains ngrok.com service: forward your localhost post to a public url (it's a reverse proxy)

Socket ​set​ method

to set a persistent value (like a cookie)

​
socket.on('nick', function(nick) {socket.set('nickname', nick);});​

then to use it:

​socket.get('nickname', function(err, nick) { // use the nickname in the callback})
  // Handle socket traffic
io.sockets.on('connection', function (socket) {
    
    // Set the nickname property for a given client
    socket.on('nick', function(nick) {
        socket.set('nickname', nick);
    });

    // Relay chat data to all clients
    socket.on('chat', function(data) {
        socket.get('nickname', function(err, nick) {
            var nickname = err ? 'Anonymous' : nick;

            var payload = {
                message: data.message,
                nick: nickname
            };

            socket.emit('chat',payload);
            socket.broadcast.emit('chat', payload);
        });
    });
});
So to clarify:

​io.sockets.on("connection", cb)​

the ​​​connection​ event happens each time a new client is connected and everything inside the callback related to that one client

​socket.emit(//...)​ and ​socket.broadcast.emit(//...)​

you can also just use ​io.sockets.emit('chat', payload)​ to broadcast to all connected clients. instead of the two lines:

socket.emit('chat',payload);
socket.broadcast.emit('chat', payload);