freenetis-github/application/helpers/expires.php @ b8a40ec0
| 8baed187 | Michal Kliment | <?php defined('SYSPATH') or die('No direct script access.');
|
|
/**
|
|||
* Controls headers that effect client caching of pages
|
|||
*
|
|||
* $Id: expires.php 1970 2008-02-06 21:54:29Z Shadowhand $
|
|||
*
|
|||
* @package Expires Helper
|
|||
* @author Kohana Team
|
|||
* @copyright (c) 2007-2008 Kohana Team
|
|||
* @license http://kohanaphp.com/license.html
|
|||
*/
|
|||
class expires {
|
|||
/**
|
|||
* Sets the amount of time before a page expires
|
|||
*
|
|||
* @param integer Seconds before the page expires
|
|||
* @return boolean
|
|||
*/
|
|||
public static function set($seconds = 60)
|
|||
{
|
|||
if (expires::check_headers())
|
|||
{
|
|||
$now = $expires = time();
|
|||
// Set the expiration timestamp
|
|||
$expires += $seconds;
|
|||
// Send headers
|
|||
header('Last-Modified: '.gmdate('D, d M Y H:i:s', $now).' GMT');
|
|||
header('Expires: '.gmdate('D, d M Y H:i:s', $expires).' GMT');
|
|||
header('Cache-Control: max-age='.$seconds);
|
|||
return $expires;
|
|||
}
|
|||
return FALSE;
|
|||
}
|
|||
/**
|
|||
* Checks to see if a page should be updated or send Not Modified status
|
|||
*
|
|||
* @param integer Seconds added to the modified time received to calculate what should be sent
|
|||
* @return bool FALSE when the request needs to be updated
|
|||
*/
|
|||
public static function check($seconds = 60)
|
|||
{
|
|||
if ( ! empty($_SERVER['HTTP_IF_MODIFIED_SINCE']) AND expires::check_headers())
|
|||
{
|
|||
if (strpos($_SERVER['HTTP_IF_MODIFIED_SINCE'], ';') !== FALSE)
|
|||
{
|
|||
// IE6 and perhaps other IE versions send length too, compensate here
|
|||
$mod_time = preg_replace('/^(.+?);/', '$1', $_SERVER['HTTP_IF_MODIFIED_SINCE']);
|
|||
}
|
|||
else
|
|||
{
|
|||
$mod_time = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
|
|||
}
|
|||
$current_time = time();
|
|||
$mod_time = strtotime($mod_time);
|
|||
$mod_time_diff = $mod_time + $seconds - $current_time;
|
|||
if ($mod_time_diff > 0)
|
|||
{
|
|||
// Re-send headers
|
|||
header('Last-Modified: '.gmdate('D, d M Y H:i:s', $mod_time).' GMT');
|
|||
header('Expires: '.gmdate('D, d M Y H:i:s', $current_time + $mod_time_diff).' GMT');
|
|||
header('Cache-Control: max-age='.$mod_time_diff);
|
|||
header('Status: 304 Not Modified', TRUE, 304);
|
|||
// Prevent any output
|
|||
Event::add('system.display', array('expires', 'prevent_output'));
|
|||
// Exit to prevent other output
|
|||
exit;
|
|||
}
|
|||
}
|
|||
return FALSE;
|
|||
}
|
|||
/**
|
|||
* Check headers already created to not step on download or Img_lib's feet
|
|||
*
|
|||
* @return boolean
|
|||
*/
|
|||
public static function check_headers()
|
|||
{
|
|||
foreach (headers_list() as $header)
|
|||
{
|
|||
if (stripos($header, 'Last-Modified:') === 0 OR stripos($header, 'Expires:') === 0)
|
|||
{
|
|||
return FALSE;
|
|||
}
|
|||
}
|
|||
return TRUE;
|
|||
}
|
|||
/**
|
|||
* Prevent any output from being displayed. Executed during system.display.
|
|||
*
|
|||
* @return void
|
|||
*/
|
|||
public static function prevent_output()
|
|||
{
|
|||
Kohana::$output = '';
|
|||
}
|
|||
} // End expires
|