Socket.io disconnects when refreshed? - node.js

Question

I am trying to build a live chat, I am using mongodb and socket.io to store the messages and users.
When a new user is created that user is stored in the mongodb and in the socket object.
If a user refreshes the page the user is removed from the socket object, meaning now in order for that person to get back in they have to create a new username and that generates a new socket.
Here is what my server side code looks like
/*
|--------------------------------------------------------------------------
| Live socket communication with front end:
|--------------------------------------------------------------------------
|
|
*/
var users = {};
io.sockets.on('connection', function (socket) {
// Listen to a new user then emit the user to all clients
socket.on('new user', function (data) {
// Check mongodb to see if the user exists and emit proper message
models.Message.findOne({username:data},function(err,user){
if(err){
console.log('something went wrong')
}
else if(user){
socket.emit('username taken', 'something');
}
else{
socket.emit('create user', data);
socket.userName = data;
socket.connected = true;
users[socket.userName] = socket;
io.sockets.emit('user name', Object.keys(users));
}
});
});
socket.on('facebook id', function(data) {
models.User.findOne({username:data.name}, function(err, user) {
if (user) {
console.log('User already exists');
socket.userName = data.name;
socket.facebook_id = data.id;
socket.connected = true;
users[socket.userName] = socket;
io.sockets.emit('user name', Object.keys(users));
}
else {
var newUser = new models.User({
username: data.name,
facebook_id: data.id
});
newUser.save(function(err, user) {
console.log('successfully inserted user/user: ' + user._id);
});
}
});
});
// Listen to a new message then emit the message to all clients
socket.on('send message', function (data, callback) {
io.sockets.emit('new message', {message: data, username: socket.userName, facebook_id: socket.facebook_id});
});
// Logic when client disconnects
socket.on('disconnect', function (data) {
if(!socket.userName) return;
seeder.disconnect(socket.userName);
delete users[socket.userName]
io.sockets.emit('user disconnected', Object.keys(users));
});
});
You see in my disconnect I remove the socket from the users object.
My question would be is there a way to save the socket info on disconnect then if the same socket tries to connect have it recognize the user and continue?
Additonal: I am thinking maybe I need to focus on creating a user login with mongodb first, then using that log in session data and pass that to the socket, creating a socket object with current database details? Does that sound like something that makes more sense, is that possible?

Answer 1

You can use cookies to identify users. Generate a random hash, put it in cookies, and thus this data will be transferred when establishing connection between client and server.
The client code may look like:
function generateHash(len) {
var symbols = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
var hash = '';
for (var i = 0; i < len; i++) {
var symIndex = Math.floor(Math.random() * symbols.length);
hash += symbols.charAt(symIndex);
}
return hash;
}
if (!/\buser_id=/.test(document.cookie)) { //if no 'user_id' in cookies
document.cookie = 'user_id=' + generateHash(32); //add cookie 'user_id'
}
//here goes establishing connection to server via `io.connect`
On the server-side you can write:
io.sockets.on('connection', function (socket) {
var cookie = socket.handshake.headers.cookie;
var match = cookie.match(/\buser_id=([a-zA-Z0-9]{32})/); //parse cookie header
var userId = match ? match[1] : null;
//...
Thus you have userId variable which is unique for each user. Then you can comment this line:
delete users[socket.userName]
because you should keep the user data.
You may now store your users object with userId (not username) as a key, and on each connection check whether users[userId] != null. And if such user exists, use their socket info