This S3 Uploader in PHP is a standalone class without any dependencies.
It is tested against DigitalOcean Spaces and currently can upload successfully. Usage is like that:
<?php
require "s3_upload_working.php";
$s3 = new S3Uploader("ams3.digitaloceanspaces.com", "xxxxxxx", "xxxxx", "bucket");
$r = $s3->uploadFile("/home/nmmm/despicable-me-2-minions_a-G-10438535-0.jpg", "/minion.jpg", "image/jpeg");
print_r($r);