130 lines
3.0 KiB
PHP
130 lines
3.0 KiB
PHP
<?php defined('SYSPATH') OR die('No direct access allowed.');
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/**
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* Controls headers that effect client caching of pages
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*
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* @package Kohana
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* @author Kohana Team
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* @copyright (c) 2007-2009 Kohana Team
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* @license http://kohanaphp.com/license
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*/
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class expires_Core {
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/**
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* Sets the amount of time before content expires
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*
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* @param integer Seconds before the content expires
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* @param integer Last modified timestamp in seconds(optional)
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* @return integer Timestamp when the content expires
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*/
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public static function set($seconds = 60, $last_modified=null)
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{
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$now = time();
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$expires = $now + $seconds;
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if (empty($last_modified))
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{
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$last_modified = $now;
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}
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header('Last-Modified: '.gmdate('D, d M Y H:i:s T', $last_modified));
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// HTTP 1.0
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header('Expires: '.gmdate('D, d M Y H:i:s T', $expires));
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// HTTP 1.1
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header('Cache-Control: public,max-age='.$seconds);
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return $expires;
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}
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/**
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* Parses the If-Modified-Since header
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*
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* @return integer|boolean Timestamp or FALSE when header is lacking or malformed
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*/
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public static function get()
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{
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if ( ! empty($_SERVER['HTTP_IF_MODIFIED_SINCE']))
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{
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// Some versions of IE6 append "; length=####"
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if (($strpos = strpos($_SERVER['HTTP_IF_MODIFIED_SINCE'], ';')) !== FALSE)
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{
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$mod_time = substr($_SERVER['HTTP_IF_MODIFIED_SINCE'], 0, $strpos);
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}
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else
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{
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$mod_time = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
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}
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return strtotime($mod_time);
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}
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return FALSE;
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}
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/**
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* Checks to see if content should be updated otherwise sends Not Modified status
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* and exits.
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*
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* @uses exit()
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* @uses expires::get()
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*
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* @param integer Maximum age of the content in seconds
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* @param integer Last modified timestamp in seconds(optional)
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* @return integer|boolean Timestamp of the If-Modified-Since header or FALSE when header is lacking or malformed
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*/
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public static function check($seconds = 60, $modified=null)
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{
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if ($last_modified = expires::get())
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{
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$now = time();
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if (empty($last_modified))
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{
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$last_modified = $now;
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}
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if ($modified <= $last_modified)
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{
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// Content has not expired
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header($_SERVER['SERVER_PROTOCOL'].' 304 Not Modified');
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header('Last-Modified: '.gmdate('D, d M Y H:i:s T', $last_modified));
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$expires = $now + $seconds;
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// HTTP 1.0
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header('Expires: '.gmdate('D, d M Y H:i:s T', $expires));
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// HTTP 1.1
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header('Cache-Control: public,max-age='.$seconds);
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// Clear any output
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Event::add('system.display', create_function('', 'Kohana::$output = "";'));
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exit;
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}
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}
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return $last_modified;
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}
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/**
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* Check if expiration headers are already set
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*
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* @return boolean
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*/
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public static function headers_set()
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{
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foreach (headers_list() as $header)
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{
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if (strncasecmp($header, 'Expires:', 8) === 0
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OR strncasecmp($header, 'Cache-Control:', 14) === 0
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OR strncasecmp($header, 'Last-Modified:', 14) === 0)
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{
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return TRUE;
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}
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}
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return FALSE;
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}
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} // End expires
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