locate.php

<?php 
if (!isset($_GET['q']))
	throw new Exception('Request is missing query parameter \'q\'');

const SERVER_MAP = [
	100 => 'eu1',
        110 => 'eu2',
        120 => 'eu3',
	200 => 'vin',
	300 => 'la',
	400 => 'chi',
	410 => 'chi2',
	420 => 'chi3',
	500 => 'brz',
	600 => 'aus',
	700 => 'sgp'
];

function demoReference($query) {
	$regex = '/stvdemos\/(([0-9]+)-[0-9_\-a-z]+\.dem)/';
	preg_match($regex, $query, $groups, PREG_OFFSET_CAPTURE, 0);

	if (sizeof($groups) != 3)
		throw new Exception('The demo reference is malformed, reference format is "stvdemos/{serverId}-{timestamp}-{map}.dem".');

	return [
		intval($groups[2][0]),
		$groups[1][0],
	];
}

function demoUrl($serverId, $fileName) {

	foreach( [intdiv($serverId, 10)*10, intdiv($serverId, 100)*100] as $providerId)
	{
		if ($provider = SERVER_MAP[$providerId])
		{
			return "//$provider.creators.tf/demos/$serverId/$fileName";
		}
	}

	throw new Exception('The demo reference does not map to any known provider.');
}


try {
	$query = $_GET['q'];
	if (isset($_GET['base64']) && $_GET['base64'] != '0') {
		$query = base64_decode($query);
	}

	[$serverId, $fileName] = demoReference($query);
	$url = demoUrl($serverId, $fileName);

	header("HTTP/2 303 See Other");
	header("Location: $url");

} catch (Exception $e) {
	header('HTTP/2 404 Not Found');
	echo "<h1>Not Found</h1>";
	echo "The demo that you have requested could not be found.";
}