handle browser refresh socket.io - socket.io

Question

I have a requirement using node js that handles disconnecting a user from a chat application.
I am not sure how to handle telling the difference between a browser closing and a user refreshing the browser.
client.on('disconnect', function () {
console.log( 'Disconnected' );
// run mysql code to remove user from logged in table
});
I have googled for a couple hours and cannot find a solution.
This seems like something pretty simple and I think it is the keywords that I am using.
Can someone point me in the right direction on how to handle this?
Thanks in advance.

Answer 1

One way would be to generate a random UID and save it to local storage. Right after the client connects, send this UID to the server and check to see if that UID exists as a connected user. On the server side, set a timeout in the disconnect that gives the user 15 seconds or so before their unique UID is deleted from the "users online" data.
Client:
// When the client starts, create the uid.
localstorage.setItem('uUID', Math.random().toString(24) + new Date());
// Emit the UID right after connection
socket.emit('userLogin', localstorage.getItem('uUID');
Server:
var currentUIDS = [];
var userIsConnected = true;
io.sockets.on('connection', function (socket) {
var currentUID = null;
socket.on('userLogin', function (data) {
if (data !== null) {
if (currentUIDS.includes(data)) {
userIsConnected = true;
currentUID = data;
}
}
});
socket.on('disconnect', function () {
userIsConnected = false;
setTimeout(function () {
if (!userIsConnected) currentUIDS.pop(currentUID);
}, 15000);
});
});

Answer 2

I have a better solution for that to handle multiple users:
var users = [],
users_connected = [];
io.on('connection', function(socket) {
var uid = null;
// register the new user
socket.on('register', function (user_uid) {
if ( users_connected.indexOf(user_uid) < 0 ) {
users_connected.push(user_uid);
}
if ( users.indexOf(user_uid) < 0 ) {
console.log('New user connected: ' + user_uid);
users.push(user_uid);
// notify other clients that a new user has joined
socket.broadcast.emit('user:join', {
name: user_uid,
users: users_connected.length
});
}
uid = user_uid;
});
// clean up when a user leaves, and broadcast it to other users
socket.on('disconnect', function () {
users_connected.splice( users_connected.indexOf(uid), 1);
setTimeout(function () {
if ( users_connected.indexOf(uid) < 0 ) {
socket.broadcast.emit('user:left', {
name: uid
});
var index = users.indexOf(uid);
users.splice(index, 1);
}
}, 3000);
});
});