Usernames in a UDP chat server with NodeJS - node.js

Question

I'm setting up a simple chat server with NodeJS that only uses a server and client. It works, and I can open up multiple client windows on the same machine, but now I need a bit more.
I would like to:
Give each client the option to set usernames
Have a client request current time from server
Action commands like "/me punches the warlock" that the server shows others as "User punches the warlock"
This sounds like a quick days work, but I just started looking at UDP and I can't quite find any examples online other than a generic server/client thing that sends and gets messages. How would I go about those tasks?
Code:
Server.js:
var dgram = require('dgram'); //import datagram to get everything needed for UDP
var PORT = 22222;
var CLIENT_PORT = 2223;
// An IP address that's reserved on each network
// Gets sent to the server
var ADDRESS = "-"; //dont want to show my IP :)
var sock = dgram.createSocket({reuseAddr: true, type: 'udp4'}); //can now open multiple clients
var current_time = Date.now(); //?
function sendMessage(data) {
sock.send(data, 0, data.length, PORT, ADDRESS, function(err){
if(err){
throw err;
}
});
}
sock.on("message", function(data, rinfo) {
//listen for messages and print them
console.log(data);
//Check if the client's port was equal to the port to find client data on
//If so, get packet
if (rinfo.port === CLIENT_PORT) {
console.log('\nreceived');
//call function to broadcast the data out to everyone on the local network
sendMessage(data);
}
//Get the string data from the data buffer.
var stringData = data.toString(); //also could be toJSON()
console.log(stringData);
//Convert that string back into a buffer by making a new Buffer and passing it in.
//The buffer class can take a string, an array or just a number of bytes to allocate to memory
var backToBuffer = new Buffer(stringData); //can take a string, array or just a size to allocate
console.log(backToBuffer);
});
//This opens the connection and starts listening
//(Client Port, Address to listen to which is ALL, What to do)
sock.bind(CLIENT_PORT, '', function(){
sock.setBroadcast(true);
console.log('listening on port ' + PORT + "\n");
});
Client.js:
var dgram = require('dgram');
var SERVER_PORT = 22222;
var PORT = 22223;
var ADDRESS = "-";
//read input from the command line
var stdin = process.stdin;
var stdout = process.stdout;
var sock = dgram.createSocket({reuseAddr: true, type: 'udp4'});
var server_sock = dgram.createSocket({reuseAddr: true, type: 'udp4'});
function sendMessage(data) {
//onsole.log("sending data");
sock.send(data, 0, data.length, PORT, ADDRESS, function(err) {
if(err) {
throw err;
}
//nsole.log("sent");
});
}
server_sock.on("message", function(data, rinfo) {
console.log("received " + data.toString());
});
server_sock.bind(SERVER_PORT, '', function() {
console.log('listening to server port');
});
sock.bind(PORT, '', function() {
sock.setBroadcast(true);
console.log("please enter a message\n");
stdin.resume();
stdin.on("data", function(data) {
sendMessage(data);
});
});

Answer 1

Node.js has loads of libraries to make realtime communication chats, I don't understand the choice of using UDP and managing everything by yourself, and it also looks that you are not very expert on this. My suggestion is to use a websocket library like it can be socket.io which they even have an example of a simple chat in their website http://socket.io/get-started/chat/
Using socket.io (or similar) it will help you a lot since it has sessions so you can save the username and return it everytime you post a message.
Below I wrote a small example of the server side (took from the index.js of the get-started above).
io.on('connection', function(socket){
var username = 'RANDOM';
socket.on('chat message', function(msg){
//here you should catch messages starting with "/" and parse them to write a different message
io.emit('chat message', username + ': ' msg);
});
socket.on('update username', function(msg) {
username = msg;
io.emit('username changed', username);
});
});
I hope it helps.