test.php

<?php

$ttl = 60*60*2; // 2 hours
parse_str($_SERVER['QUERY_STRING'], $q);
$out = array();

if (!empty($q['r']) && function_exists('apc_fetch')) {

	if (!apc_exists('test-' . $q['r'])) {
		header("Status: 404 Not Found");
		die;
	} else {
		$out = apc_fetch('test-' . $q['r']);
	}

} else {

	ksort($_SERVER);
	reset($_SERVER);
	$out = array(
	'_SERVER' => array_filter($_SERVER,
		function($val) use (&$_SERVER) {
			$key = key($_SERVER);
			next($_SERVER);
			return preg_match("/^REQUEST|CONTENT|REMOTE|SERVER|QUERY|HTTP/", $key);
		}
	),
	'_GET' => $_GET,
	'_POST' => $_POST,
	'_COOKIE' => $_COOKIE,
	);

	if (function_exists('apc_store')) {
		$uid = base_convert(microtime(true), 10, 36);
		$out['SAVED_REQUEST'] = 'http://' . $_SERVER['HTTP_HOST'] . '/?r=' . $uid;
		if (!apc_store('test-'.$uid, $out, $ttl)) {
			unset($out['request_url']);
		} else {
			header('X-Request-Id: ' . $uid);
		}
	}
}

if (!empty($_SERVER['HTTP_ACCEPT']) && $_SERVER['HTTP_ACCEPT'] == 'application/json') {
	header('Content-Type: application/json');
	echo json_encode($out);
} else {
	header('Content-Type: text/plain');
	var_export($out);
}