<?php
stream_context_set_default(array('http'=>array('method'=>'HEAD')));

$file = $_GET['file'];

$url = 'https://archive.archlinux.org/repos/last/' . urlencode($file);
$h = get_headers($url);
if (strpos($h[0], "200"))
{
    header('Location: ' . $url);
}
else
{
    preg_match("@([^/]+)-.+-.+-.+$@", $file, $match);
    $url = 'https://archive.archlinux.org/packages/' . urlencode($match[1][0]) . '/' . urlencode($match[1]) . '/' . urlencode($match[0]);
    header('Location: ' . $url);
}
?>