Regarding base64url, you can just use:
<?php
$encodedUrl = urlencode(base64_encode($string));
$decodedUrl = base64_decode(url_decode($string));
?>
Regarding base64url, you can just use:
<?php
$encodedUrl = urlencode(base64_encode($string));
$decodedUrl = base64_decode(url_decode($string));
?>