Added TCachePageStatePersister

1 files changed, 202 insertions, 0 deletions

diff --git a/framework/Web/UI/TCachePageStatePersister.php b/framework/Web/UI/TCachePageStatePersister.php
new file mode 100644
index 00000000..3e793195
--- /dev/null
+++ b/framework/Web/UI/TCachePageStatePersister.php
@@ -0,0 +1,202 @@
+<?php

+/**

+ * TCachePageStatePersister class file

+ *

+ * @author Qiang Xue <qiang.xue@gmail.com>

+ * @link http://www.pradosoft.com/

+ * @copyright Copyright &copy; 2005-2007 PradoSoft

+ * @license http://www.pradosoft.com/license/

+ * @version $Id$

+ * @package System.Web.UI

+ */

+

+/**

+ * TCachePageStatePersister class

+ *

+ * TCachePageStatePersister implements a page state persistent method based on cache.

+ * Page state are stored in cache (e.g. memcache, DB cache, etc.), and only a small token

+ * is passed to the client side to identify the state. This greatly reduces the size of

+ * the page state that needs to be transmitted between the server and the client. Of course,

+ * this is at the cost of using server side resource.

+ *

+ * A cache module has to be loaded in order to use TCachePageStatePersister.

+ * By default, TCachePageStatePersister will use the primary cache module.

+ * A non-primary cache module can be used by setting {@link setCacheModuleID CacheModuleID}.

+ * Any cache module, as long as it implements the interface {@link ICache}, may be used.

+ * For example, one can use {@link TDbCache}, {@link TMemCache}, {@link TAPCCache}, etc.

+ *

+ * TCachePageStatePersister uses {@link setCacheTimeout CacheTimeout} to limit the data

+ * that stores in cache.

+ *

+ * Since server resource is often limited, be cautious if you plan to use TCachePageStatePersister

+ * for high-traffic Web pages. You may consider using a small {@link setCacheTimeout CacheTimeout}.

+ *

+ * There are a couple of ways to use TCachePageStatePersister.

+ * One can override the page's {@link TPage::getStatePersister()} method and

+ * create a TCachePageStatePersister instance there.

+ * Or one can configure the pages to use TCachePageStatePersister in page configurations

+ * as follows,

+ * <code>

+ *   <pages StatePersisterClass="System.Web.UI.TCachePageStatePersister"

+ *          StatePersister.CacheModuleID="mycache"

+ *          StatePersister.CacheTimeout="3600" />

+ * </code>

+ * Note in the above, we use StatePersister.CacheModuleID to configure the cache module ID

+ * for the TCachePageStatePersister instance.

+ *

+ * The above configuration will affect the pages under the directory containing

+ * this configuration and all its subdirectories.

+ * To configure individual pages to use TCachePageStatePersister, use

+ * <code>

+ *   <pages>

+ *     <page id="PageID" StatePersisterClass="System.Web.UI.TCachePageStatePersister" />

+ *   </pages>

+ * </code>

+ *

+ * @author Qiang Xue <qiang.xue@gmail.com>

+ * @version $Id$

+ * @package System.Web.UI

+ * @since 3.1.1

+ */

+class TCachePageStatePersister extends TComponent implements IPageStatePersister

+{

+	private $_prefix='statepersister';

+	private $_page;

+	private $_cache=null;

+	private $_cacheModuleID='';

+	private $_timeout=1800;

+

+	/**

+	 * @param TPage the page that this persister works for

+	 */

+	public function getPage()

+	{

+		return $this->_page;

+	}

+

+	/**

+	 * @param TPage the page that this persister works for.

+	 */

+	public function setPage(TPage $page)

+	{

+		$this->_page=$page;

+	}

+

+	/**

+	 * @return string the ID of the cache module.

+	 */

+	public function getCacheModuleID()

+	{

+		return $this->_cacheModuleID;

+	}

+

+	/**

+	 * @param string the ID of the cache module. If not set, the primary cache module will be used.

+	 */

+	public function setCacheModuleID($value)

+	{

+		$this->_cacheModuleID=$value;

+	}

+

+	/**

+	 * @return ICache the cache module being used for data storage

+	 */

+	public function getCache()

+	{

+		if($this->_cache===null)

+		{

+			if($this->_cacheModuleID!=='')

+				$cache=Prado::getApplication()->getModule($this->_cacheModuleID);

+			else

+				$cache=Prado::getApplication()->getCache();

+			if($cache===null || !($cache instanceof ICache))

+			{

+				if($this->_cacheModule!=='')

+					throw new TConfigurationException('cachepagestatepersister_cachemoduleid_invalid',$this->_cacheModuleID);

+				else

+					throw new TConfigurationException('cachepagestatepersister_cache_required');

+			}

+			$this->_cache=$cache;

+		}

+		return $this->_cache;

+	}

+

+	/**

+	 * @return integer the number of seconds in which the cached state will expire. Defaults to 1800.

+	 */

+	public function getCacheTimeout()

+	{

+		return $this->_timeout;

+	}

+

+	/**

+	 * @param integer the number of seconds in which the cached state will expire. 0 means never expire.

+	 * @throws TInvalidDataValueException if the number is smaller than 0.

+	 */

+	public function setCacheTimeout($value)

+	{

+		if(($value=TPropertyValue::ensureInteger($value))>=0)

+			$this->_timeout=$value;

+		else

+			throw new TInvalidDataValueException('cachepagestatepersister_timeout_invalid');

+	}

+

+	/**

+	 * @return string prefix of cache variable name to avoid conflict with other cache data. Defaults to 'statepersister'.

+	 */

+	public function getKeyPrefix()

+	{

+	    return $this->_prefix;

+	}

+

+	/**

+     * @param string prefix of cache variable name to avoid conflict with other cache data

+     */

+	public function setKeyPrefix($value)

+	{

+	    $this->_prefix=$value;

+	}

+

+	/**

+	 * @param string micro timestamp when saving state occurs

+	 * @return string a key that is unique per user request

+	 */

+	protected function calculateKey($timestamp)

+	{

+		return $this->getKeyPrefix().':'

+			. $this->_page->getRequest()->getUserHostAddress()

+			. $this->_page->getPagePath()

+			. $timestamp;

+	}

+

+	/**

+	 * Saves state in cache.

+	 * @param mixed state to be stored

+	 */

+	public function save($state)

+	{

+		$data=serialize($state);

+		$timestamp=(string)microtime(true);

+		$key=$this->calculateKey($timestamp);

+		$this->getCache()->add($key,$data,$this->_timeout);

+		$this->_page->setClientState(TPageStateFormatter::serialize($this->_page,$timestamp));

+	}

+

+	/**

+	 * Loads page state from cache.

+	 * @return mixed the restored state

+	 * @throws THttpException if page state is corrupted

+	 */

+	public function load()

+	{

+		if(($timestamp=TPageStateFormatter::unserialize($this->_page,$this->_page->getRequestClientState()))!==null)

+		{

+			$key=$this->calculateKey($timestamp);

+			if(($data=$this->getCache()->get($key))!==false)

+				return unserialize($data);

+		}

+		throw new THttpException(400,'cachepagestatepersister_pagestate_corrupted');

+	}

+}

+

+?>
\ No newline at end of file