<?php /** * HTTP utility methods * * @package Sabre * @subpackage HTTP * @copyright Copyright (C) 2007-2012 Rooftop Solutions. All rights reserved. * @author Evert Pot (http://www.rooftopsolutions.nl/) * @author Paul Voegler * @license http://code.google.com/p/sabredav/wiki/License Modified BSD License */ class Sabre_HTTP_Util { /** * Parses a RFC2616-compatible date string * * This method returns false if the date is invalid * * @param string $dateHeader * @return bool|DateTime */ static function parseHTTPDate($dateHeader) { //RFC 2616 section 3.3.1 Full Date //Only the format is checked, valid ranges are checked by strtotime below $month = '(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)'; $weekday = '(Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday)'; $wkday = '(Mon|Tue|Wed|Thu|Fri|Sat|Sun)'; $time = '[0-2]\d(\:[0-5]\d){2}'; $date3 = $month . ' ([1-3]\d| \d)'; $date2 = '[0-3]\d\-' . $month . '\-\d\d'; //4-digit year cannot begin with 0 - unix timestamp begins in 1970 $date1 = '[0-3]\d ' . $month . ' [1-9]\d{3}'; //ANSI C's asctime() format //4-digit year cannot begin with 0 - unix timestamp begins in 1970 $asctime_date = $wkday . ' ' . $date3 . ' ' . $time . ' [1-9]\d{3}'; //RFC 850, obsoleted by RFC 1036 $rfc850_date = $weekday . ', ' . $date2 . ' ' . $time . ' GMT'; //RFC 822, updated by RFC 1123 $rfc1123_date = $wkday . ', ' . $date1 . ' ' . $time . ' GMT'; //allowed date formats by RFC 2616 $HTTP_date = "($rfc1123_date|$rfc850_date|$asctime_date)"; //allow for space around the string and strip it $dateHeader = trim($dateHeader, ' '); if (!preg_match('/^' . $HTTP_date . '$/', $dateHeader)) return false; //append implicit GMT timezone to ANSI C time format if (strpos($dateHeader, ' GMT') === false) $dateHeader .= ' GMT'; $realDate = strtotime($dateHeader); //strtotime can return -1 or false in case of error if ($realDate !== false && $realDate >= 0) return new DateTime('@' . $realDate, new DateTimeZone('UTC')); } /** * Transforms a DateTime object to HTTP's most common date format. * * We're serializing it as the RFC 1123 date, which, for HTTP must be * specified as GMT. * * @param DateTime $dateTime * @return string */ static function toHTTPDate(DateTime $dateTime) { // We need to clone it, as we don't want to affect the existing // DateTime. $dateTime = clone $dateTime; $dateTime->setTimeZone(new DateTimeZone('GMT')); return $dateTime->format('D, d M Y H:i:s \G\M\T'); } }