<?php
/**
 * Copyright (c) 2011 Bart Visscher bartv@thisnet.nl
 * This file is licensed under the Affero General Public License version 3 or
 * later.
 * See the COPYING-README file.
 */

class OC_Response {
	const STATUS_NOT_MODIFIED = 304;

	static public function enableCaching() {
		header('Cache-Control: cache');
		header('Pragma: cache');
	}

	static public function setStatus($status) {
		switch($status) {
			case self::STATUS_NOT_MODIFIED:
				$status = $status . ' Not Modified';
				break;
		}
		header($_SERVER["SERVER_PROTOCOL"].' '.$status);
	}

	static public function setETagHeader($etag) {
		if (empty($etag)) {
			return;
		}
		self::enableCaching();
		if (isset($_SERVER['HTTP_IF_NONE_MATCH']) &&
		    trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
			self::setStatus(self::STATUS_NOT_MODIFIED);
			exit;
		}
		header('ETag: '.$etag);
	}

	static public function setLastModifiedHeader($lastModified) {
		if (empty($lastModified)) {
			return;
		}
		if ($lastModified instanceof DateTime) {
			$lastModified = $lastModified->format(DateTime::RFC2822);
		}
		self::enableCaching();
		if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) &&
		    trim($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $lastModified) {
			self::setStatus(self::STATUS_NOT_MODIFIED);
			exit;
		}
		header('Last-Modified: '.$lastModified);
	}
}