Index: typo3/sysext/cms/tslib/interfaces/interface.tslib_fe_setpagecachecontenthook.php
===================================================================
--- typo3/sysext/cms/tslib/interfaces/interface.tslib_fe_setpagecachecontenthook.php	(revision 0)
+++ typo3/sysext/cms/tslib/interfaces/interface.tslib_fe_setpagecachecontenthook.php	(revision 0)
@@ -0,0 +1,51 @@
+<?php
+/***************************************************************
+*  Copyright notice
+*
+*  (c) 2008 Martin Holtz <typo3@martinholtz.de>
+*  All rights reserved
+*
+*  This script is part of the TYPO3 project. The TYPO3 project is
+*  free software; you can redistribute it and/or modify
+*  it under the terms of the GNU General Public License as published by
+*  the Free Software Foundation; either version 2 of the License, or
+*  (at your option) any later version.
+*
+*  The GNU General Public License can be found at
+*  http://www.gnu.org/copyleft/gpl.html.
+*  A copy is found in the textfile GPL.txt and important notices to the license
+*  from the author is found in LICENSE.txt distributed with these scripts.
+*
+*
+*  This script is distributed in the hope that it will be useful,
+*  but WITHOUT ANY WARRANTY; without even the implied warranty of
+*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*  GNU General Public License for more details.
+*
+*  This copyright notice MUST APPEAR in all copies of the script!
+***************************************************************/
+
+
+/**
+ * interface for classes which hook into tslib_fe for changing the cache expires timestamp
+ *
+ * @author	Martin Holtz <typo3@martinholtz.de>
+ * @package TYPO3
+ * @subpackage t3lib
+ */
+interface tslib_fe_setPageCacheContentHook {
+	
+	/**
+	 * expiresTimestamp which is be used to store the cache-page
+	 * can be altered from extensions
+	 *
+	 * @param	int			Timestamp, which defines when the page-cache is outdated 
+	 * @param	int			Page ID
+	 * @param	mixed		The additional cache_data array, fx. $this->config		
+	 * @return	int			new Timestamp
+	 */
+	public function getCacheExpiresTimestamp($contentObjectName, array $configuration, $TypoScriptKey, tslib_cObj &$parentObject);
+
+}
+
+?>\ No newline at end of file
Index: typo3/sysext/cms/tslib/class.tslib_fe.php
===================================================================
--- typo3/sysext/cms/tslib/class.tslib_fe.php	(revision 4068)
+++ typo3/sysext/cms/tslib/class.tslib_fe.php	(working copy)
@@ -2689,7 +2689,6 @@
 			}
 		}
 	}
-
 	/**
 	 * Sets cache content; Inserts the content string into the cache_pages table.
 	 *
@@ -2699,8 +2698,80 @@
 	 * @return	void
 	 * @see realPageCacheContent(), tempPageCacheContent()
 	 */
-	function setPageCacheContent($content,$data,$tstamp)	{
+	function setPageCacheContent($content, $data, $tstamp) {
 		$this->clearPageCacheContent();
+
+			// only if content is not "message_page_is_being_generated"
+			// which expires after 30 seconds
+		if (!$this->tempContent) {
+				// can be changed from an extension via $GLOBALS['TSFE']->cacheExpires
+			if ($this->cacheExpires > 0 && $this->cacheExpires < $tstamp) {
+				$tstamp = $this->cacheExpires;
+			}
+
+				// Call hook for $tstamp calculation
+			if(is_array($TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['setPageCacheContent'])) {
+				foreach($TYPO3_CONF_VARS['SC_OPTIONS']['tslib/class.tslib_fe.php']['setPageCacheContent'] as $classData) {
+					$hookObject = &t3lib_div::getUserObj($classData);
+
+					if(!($hookObject instanceof tslib_fe_setPageCacheContentHook)) {
+						throw new UnexpectedValueException(
+							'$hookObject must implement interface tslib_content_tslib_fe_setPageCacheContentHook',
+							1220839864
+						);
+					}
+					$modifiedTimestamp = $hookObject->getCacheExpiresTimestamp($tstamp, $this->id, $data);
+
+					if ($modifiedTimestamp > 0 && $modifiedTimestamp < $tstamp) {
+						$tstamp = $modifiedTimestamp;
+					}
+				}
+			}
+
+			$pageSelect = t3lib_div::makeInstance('t3lib_pageSelect');
+
+				// Workspace does not matter, because they are on an different page
+				// so whe can use $this-id to check for content elements on this page
+				// Versioning does not matter, because they got pid = -1
+			$res = $GLOBALS['TYPO3_DB']->exec_SELECTquery(
+				'*',
+				'tt_content',
+				'tt_content.pid = '.intval($this->id)
+					. ' AND (
+							(tt_content.starttime > '.$GLOBALS['EXEC_TIME'].' AND tt_content.starttime < '.$tstamp.')
+							OR (tt_content.endtime > '.$GLOBALS['EXEC_TIME'].' AND tt_content.endtime < '.$tstamp.')
+							) '
+					. $pageSelect->enableFields(
+						'tt_content',
+						0,
+						array('starttime' => true, 'endtime' => true),
+						FALSE
+					)
+			);
+
+			while ($row = $GLOBALS['TYPO3_DB']->sql_fetch_assoc($res)) {
+					// $tstamp is the orignial expire-date of that page
+					// usually it is calculated by cache-expiredate and
+					// $GLOBALS['EXEC_TIME']
+					// the page starttime/endtime is checked before
+					// it is requested from cache. So we do not have to care
+					// of starttime/endtime of the page itself
+
+					// we want to respect the starttime / endtime of the
+					// content elements
+					//
+					// we have to check for each content element only, if it has a starttime
+					// or an endtime which takes effect betwwen $GLOBALS['EXEC_TIME']
+					// and the default-expire date ($tstamp).
+				if ($row['starttime'] < $tstamp && $row['starttime'] > $GLOBALS['EXEC_TIME']) {
+					$tstamp = $row['starttime'];
+				}
+				if ($row['endtime'] < $tstamp && $row['endtime'] > $GLOBALS['EXEC_TIME']) {
+					$tstamp = $row['endtime'];
+				}
+			}
+		}
+
 		$insertFields = array(
 			'hash' => $this->newHash,
 			'page_id' => $this->id,