From 3413fe6bfd423d45d083ff4ed62c0f72c2cc272f Mon Sep 17 00:00:00 2001
From: Bharat Mediratta <bharat@menalto.com>
Date: Thu, 28 May 2009 06:11:53 +0800
Subject: Rename 'kohana' to 'system' to conform to the Kohana filesystem
 layout.  I'm comfortable with us not clearly drawing the distinction about
 the fact that it's Kohana.

Signed-off-by: Gallery Role Account <gallery@menalto.com>
---
 system/helpers/expires.php | 111 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 system/helpers/expires.php

(limited to 'system/helpers/expires.php')

diff --git a/system/helpers/expires.php b/system/helpers/expires.php
new file mode 100644
index 00000000..c43cc0cc
--- /dev/null
+++ b/system/helpers/expires.php
@@ -0,0 +1,111 @@
+<?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
\ No newline at end of file
-- 
cgit v1.2.3