From d1384deb9b3ac872defd08fd01fbf8cf11442b45 Mon Sep 17 00:00:00 2001
From: xue <>
Date: Wed, 4 Jan 2006 04:59:01 +0000
Subject: Added documentation.

---
 framework/Web/UI/TPageStatePersister.php | 67 ++++++++++++++++++++++++++++++--
 1 file changed, 63 insertions(+), 4 deletions(-)

(limited to 'framework/Web/UI/TPageStatePersister.php')

diff --git a/framework/Web/UI/TPageStatePersister.php b/framework/Web/UI/TPageStatePersister.php
index 9c9954de..d312ed84 100644
--- a/framework/Web/UI/TPageStatePersister.php
+++ b/framework/Web/UI/TPageStatePersister.php
@@ -1,12 +1,44 @@
 <?php
+/**
+ * TPageStatePersister class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $  $Date: $
+ * @package System.Web.UI
+ */
 
+/**
+ * TPageStatePersister class
+ *
+ * TPageStatePersister implements a page state persistent method based on
+ * form hidden fields. It is the default way of storing page state.
+ * Should you need to access this module, you may get it via
+ * {@link TPageService::getPageStatePersister}.
+ *
+ * TPageStatePersister uses a private key to generate a private unique hash
+ * code to prevent the page state from being tampered.
+ * By default, the private key is a randomly generated string.
+ * You may specify it explicitly by setting the {@link setPrivateKey PrivateKey} property.
+ * This may be useful if your application is running on a server farm.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System.Web.UI
+ * @since 3.0
+ */
 class TPageStatePersister extends TModule implements IStatePersister
 {
+	/**
+	 * @var string private key
+	 */
 	private $_privateKey=null;
 
 	/**
-	 * Initializes the service.
-	 * This method is required by IModule interface.
+	 * Registers the module with the page service.
+	 * This method is required by IModule interface and is invoked when the module is initialized.
 	 * @param TXmlElement module configuration
 	 */
 	public function init($config)
@@ -14,6 +46,10 @@ class TPageStatePersister extends TModule implements IStatePersister
 		$this->getService()->setPageStatePersister($this);
 	}
 
+	/**
+	 * Saves state in hidden fields.
+	 * @param mixed state to be stored
+	 */
 	public function save($state)
 	{
 		$data=Prado::serialize($state);
@@ -25,6 +61,11 @@ class TPageStatePersister extends TModule implements IStatePersister
 		$this->getService()->getRequestedPage()->getClientScript()->registerHiddenField(TPage::FIELD_PAGESTATE,base64_encode($data));
 	}
 
+	/**
+	 * Loads page state from hidden fields.
+	 * @return mixed the restored state
+	 * @throws THttpException if page state is corrupted
+	 */
 	public function load()
 	{
 		$str=base64_decode($this->getApplication()->getRequest()->getItems()->itemAt(TPage::FIELD_PAGESTATE));
@@ -41,9 +82,14 @@ class TPageStatePersister extends TModule implements IStatePersister
 			if($hmac===$this->computeHMAC($state,$this->getPrivateKey()))
 				return Prado::unserialize($state);
 		}
-		throw new TInvalidDataValueException('pagestatepersister_viewstate_corrupted.');
+		throw new THttpException(400,'pagestatepersister_pagestate_corrupted');
 	}
 
+	/**
+	 * Generates a random private key used for hashing the state.
+	 * You may override this method to provide your own way of private key generation.
+	 * @return string  the rondomly generated private key
+	 */
 	protected function generatePrivateKey()
 	{
 		$v1=rand();
@@ -52,6 +98,9 @@ class TPageStatePersister extends TModule implements IStatePersister
 		return md5("$v1$v2$v3");
 	}
 
+	/**
+	 * @return string private key used for hashing the state.
+	 */
 	public function getPrivateKey()
 	{
 		if(empty($this->_privateKey))
@@ -65,13 +114,23 @@ class TPageStatePersister extends TModule implements IStatePersister
 		return $this->_privateKey;
 	}
 
+	/**
+	 * @param string private key used for hashing the state.
+	 * @throws TInvalidDataValueException if the length of the private key is shorter than 8.
+	 */
 	public function setPrivateKey($value)
 	{
 		if(strlen($value)<8)
-			throw new TConfigurationException('pagestatepersister_privatekey_invalid');
+			throw new TInvalidDataValueException('pagestatepersister_privatekey_invalid');
 		$this->_privateKey=$value;
 	}
 
+	/**
+	 * Computes a hashing code based on the input data and the private key.
+	 * @param string input data
+	 * @param string the private key
+	 * @return string the hashing code
+	 */
 	private function computeHMAC($data,$key)
 	{
 		if (strlen($key) > 64)
-- 
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