Initial Kohana install

[speedfreak] / Server / system / helpers / expires.php

diff --git a/Server/system/helpers/expires.php b/Server/system/helpers/expires.php
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+++ b/Server/system/helpers/expires.php
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+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * Controls headers that effect client caching of pages
+ *
+ * $Id: expires.php 4272 2009-04-25 21:47:26Z zombor $
+ *
+ * @package    Core
+ * @author     Kohana Team
+ * @copyright  (c) 2007-2008 Kohana Team
+ * @license    http://kohanaphp.com/license.html
+ */
+class expires_Core {
+
+       /**
+        * 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 T', $now));
+                       header('Expires: '.gmdate('D, d M Y H:i:s T', $expires));
+                       header('Cache-Control: max-age='.$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 = strpos($_SERVER['HTTP_IF_MODIFIED_SINCE'], ';')) !== FALSE)
+                       {
+                               // IE6 and perhaps other IE versions send length too, compensate here
+                               $mod_time = substr($_SERVER['HTTP_IF_MODIFIED_SINCE'], 0, $strpos);
+                       }
+                       else
+                       {
+                               $mod_time = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
+                       }
+
+                       $mod_time = strtotime($mod_time);
+                       $mod_time_diff = $mod_time + $seconds - time();
+
+                       if ($mod_time_diff > 0)
+                       {
+                               // Re-send headers
+                               header('Last-Modified: '.gmdate('D, d M Y H:i:s T', $mod_time));
+                               header('Expires: '.gmdate('D, d M Y H:i:s T', time() + $mod_time_diff));
+                               header('Cache-Control: max-age='.$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 $header)
+               {
+                       if ((session_cache_limiter() == '' AND stripos($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
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