Generates a UUID in 8-4-4-4-12 notation

uuid.php

<?php

function uuid() {
    $s = bin2hex(random_bytes(16));
    
    return sprintf('%s-%s-%s-%s-%s',
        substr($s, 0, 8),
        substr($s, 8, 4),
        substr($s, 12, 4),
        substr($s, 16, 4),
        substr($s, 20, 12)
    );
}