PHP - Give access to only one device at a time

Question

I want to make a simple website on a local server that would be accessed by only one device at a time. I've found user management scripts but they are more more complex than what I am searching for. I don't need it to be password protected or have different kind of users and/or rights. Juste a page where only one person at a time can connect.

Is there a way to make it in PHP ?

I've first searched for an option in my server (lighttpd) then for some kind of htaccess but I think PHP is the only way to do it right.

Thank you for your consideration.

Answer 1

According to my comment above:

<?php

$minInterval = 5 * 60; // 5 minutes
$access = true;

if (file_exists('visitor')) {
    $visitor = unserialize(file_get_contents('visitor'));

    if ($visitor['addr'] != $_SERVER['REMOTE_ADDR']) {
        if ($visitor['time'] + $minInterval >= time()) {
            $access = false;
        }
    }
}

if (!$access) {
    exit('Access denied.');
} else {
    // Update last visitor data
    file_put_contents('visitor', serialize([
        'addr' => $_SERVER['REMOTE_ADDR'],
        'time' => time()
    ]));
}