Change the status (online/offline) in the bank when closing the page

Question

I’m making a chat system for a panel, and I already have it ready practically, everything connected to the database, when it login changes to online and when it comes out(click the button) it changes to offline in db.

The problem is, when the user closes the page, I need the bank to be changed to offline, I tried to use the onbeforeunload as I saw in a forum to do the update as ta the code below, I tried to use the same to make the change when it opens the page again, but is not effecting, I think by a code hierarchy.

I don’t really understand the JS/Jquery and AJAX very well, so I’m a little lost in this question.

window.onbeforeunload = function () {
        atualiza_fecho();
    };
    function atualiza_fecho(){
        $.get('assets/inc/offline.php', function(resultado){})
    }

Code from offline.php

<?php
session_start();
$session_id = $_SESSION['uid'];
$mysqli = mysqli_connect('localhost', 'root', '');
mysqli_select_db($mysqli, 'cbr_chat');
$q=mysqli_query($mysqli, "UPDATE users SET status = 'offline' WHERE uid = '$session_id'");
?>

The idea is, I closed the page, it doesn’t end my session and only changes the status in the bank to offline, and when I open the page again, it changes to online, all this, without finishing the session or having to log in again.

Answer 1

Probably the most viable alternative is to use some key bank/value for this, such as the Redis or memcache.

In these banks, there is usually the option of timeout for the database registration, then you can have ajax update the key and "reinvigorate" the cache timeout. Therefore, if the user ID is in the cache, it means it will be online, and otherwise offline.

I hope I’ve helped. ;)