Added an alternate implementation for storing "transaction" identifiers on disk instead of inside the $_SESSION variable.

git-svn-id: http://svn.code.sf.net/p/itop/code/trunk@3598 a333f486-631f-4898-b8df-5754b55c2be0

application/transaction.class.inc.php

@@ -1,5 +1,5 @@
 <?php
-// Copyright (C) 2010-2012 Combodo SARL
+// Copyright (C) 2010-2015 Combodo SARL
 //
 //   This file is part of iTop.
 //
@@ -19,7 +19,8 @@
 /**
  * This class records the pending "transactions" corresponding to forms that have not been
  * submitted yet, in order to prevent double submissions. When created a transaction remains valid
- * until the user's session expires
+ * until the user's session expires. This class is actually a wrapper to the underlying implementation
+ * which choice is configured via the parameter 'transaction_storage'
  *  
  * @package     iTop
  * @copyright   Copyright (C) 2010-2012 Combodo SARL
@@ -36,6 +37,66 @@ class privUITransaction
 	 */
 	public static function GetNewTransactionId()
 	{
+		$sClass = 'privUITransaction'.MetaModel::GetConfig()->Get('transaction_storage');
+		if (!class_exists($sClass, false))
+		{
+			IssueLog::Error("Incorrect value '".MetaModel::GetConfig()->Get('transaction_storage')."' for 'transaction_storage', the class '$sClass' does not exists. Using privUITransactionSession instead for storing sessions.");
+			$sClass = 'privUITransactionSession';
+		}
+
+		return (string)$sClass::GetNewTransactionId();
+	}
+
+	/**
+	 * Check whether a transaction is valid or not and (optionally) remove the valid transaction from
+	 * the session so that another call to IsTransactionValid for the same transaction id
+	 * will return false
+	 * @param int $id Identifier of the transaction, as returned by GetNewTransactionId
+	 * @param bool $bRemoveTransaction True if the transaction must be removed
+	 * @return bool True if the transaction is valid, false otherwise
+	 */
+	public static function IsTransactionValid($id, $bRemoveTransaction = true)
+	{
+		$sClass = 'privUITransaction'.MetaModel::GetConfig()->Get('transaction_storage');
+		if (!class_exists($sClass, false))
+		{
+			$sClass = 'privUITransactionSession';
+		}
+		
+		return $sClass::IsTransactionValid($id, $bRemoveTransaction);
+	}
+
+	/**
+	 * Removes the transaction specified by its id
+	 * @param int $id The Identifier (as returned by GetNewTranscationId) of the transaction to be removed.
+	 * @return void
+	 */
+	public static function RemoveTransaction($id)
+	{
+		$sClass = 'privUITransaction'.MetaModel::GetConfig()->Get('transaction_storage');
+		if (!class_exists($sClass, false))
+		{
+			$sClass = 'privUITransactionSession';
+		}
+		
+		$sClass::RemoveTransaction($id);
+	}
+}
+
+/**
+ * The original (and by default) mechanism for storing transaction information
+ * as an array in the $_SESSION variable
+ *
+ */
+class privUITransactionSession
+{
+	/**
+	 * Create a new transaction id, store it in the session and return its id
+	 * @param void
+	 * @return int The identifier of the new transaction
+	 */
+	public static function GetNewTransactionId()
+	{
 		if (!isset($_SESSION['transactions']))
 		{
 				$_SESSION['transactions'] = array();
@@ -99,4 +160,129 @@ class privUITransaction
 		}		
 	}
 }
-?>
+
+/**
+ * An alternate implementation for storing the transactions as temporary files
+ * Useful when using an in-memory storage for the session which do not
+ * guarantee mutual exclusion for writing
+ */
+class privUITransactionFile
+{
+	/**
+	 * Create a new transaction id, store it in the session and return its id
+	 * @param void
+	 * @return int The identifier of the new transaction
+	 */
+	public static function GetNewTransactionId()
+	{
+		if (!is_dir(APPROOT.'data/transactions'))
+		{
+			if (!is_writable(APPROOT.'data'))
+			{
+				throw new Exception('The directory "'.APPROOT.'data" must be writable to the application.');
+			}
+			if (!@mkdir(APPROOT.'data/transactions'))
+			{
+				throw new Exception('Failed to create the directory "'.APPROOT.'data/transactions". Ajust the rights on the parent directory or let an administrator create the transactions directory and give the web sever enough rights to write into it.');
+			}
+		}
+		if (!is_writable(APPROOT.'data/transactions'))
+		{
+			throw new Exception('The directory "'.APPROOT.'data/transactions" must be writable to the application.');
+		}
+		self::CleanupOldTransactions();
+		$id = basename(tempnam(APPROOT.'data/transactions', substr(UserRights::GetUser(), 0, 10).'-'));
+		IssueLog::Info('GetNewTransactionId: Created transaction: '.$id);
+
+		return (string)$id;
+	}
+
+	/**
+	 * Check whether a transaction is valid or not and (optionally) remove the valid transaction from
+	 * the session so that another call to IsTransactionValid for the same transaction id
+	 * will return false
+	 * @param int $id Identifier of the transaction, as returned by GetNewTransactionId
+	 * @param bool $bRemoveTransaction True if the transaction must be removed
+	 * @return bool True if the transaction is valid, false otherwise
+	 */
+	public static function IsTransactionValid($id, $bRemoveTransaction = true)
+	{
+		$bResult = file_exists(APPROOT.'data/transactions/'.$id);
+		if ($bResult)
+		{
+			if ($bRemoveTransaction)
+			{
+				$bResult = @unlink(APPROOT.'data/transactions/'.$id);
+				if (!$bSuccess)
+				{
+					IssueLog::Error('IsTransactionValid: FAILED to remove transaction '.$id);
+				}
+				else
+				{
+					IssueLog::Info('IsTransactionValid: Removed transaction: '.$id);
+				}
+			}
+		}
+		else
+		{
+			IssueLog::Info("IsTransactionValid: Transaction '$id' not found. Pending transactions for this user:\n".implode("\n", self::GetPendingTransactions()));
+		}
+		return $bResult;
+	}
+
+	/**
+	 * Removes the transaction specified by its id
+	 * @param int $id The Identifier (as returned by GetNewTransactionId) of the transaction to be removed.
+	 * @return void
+	 */
+	public static function RemoveTransaction($id)
+	{
+		$bSuccess = true;
+		if(!file_exists(APPROOT.'data/transactions/'.$id))
+		{
+			$bSuccess = false;
+			IssueLog::Info("RemoveTransaction: Transaction '$id' not found. Pending transactions for this user:\n".implode("\n", self::GetPendingTransactions()));
+		}
+		$bSuccess = @unlink(APPROOT.'data/transactions/'.$id);
+		if (!$bSuccess)
+		{
+			IssueLog::Error('RemoveTransaction: FAILED to remove transaction '.$id);
+		}
+		return $bSuccess;
+	}
+
+	/**
+	 * Cleanup old transactions which have been pending since more than 24 hours
+	 */
+	protected static function CleanupOldTransactions()
+	{
+		$iLimit = time() - 24*3600;
+		$aTransactions = glob(APPROOT.'data/transactions/*-*');
+		foreach($aTransactions as $sFileName)
+		{
+			if (filectime($sFileName) < $iLimit)
+			{
+				@unlink($sFileName);
+			}
+		}
+	}
+
+	/**
+	 * For debugging purposes: gets the pending transactions of the current user
+	 * as an array, with the date of the creation of the transaction file
+	 */
+	protected static function GetPendingTransactions()
+	{
+		clearstatcache();
+		$aResult = array();
+		$aTransactions = glob(APPROOT.'data/transactions/'.UserRights::GetUser().'-*');
+		foreach($aTransactions as $sFileName)
+		{
+			$aResult[] = date('Y-m-d H:i:s', filectime($sFileName)).' - '.basename($sFileName);
+		}
+		sort($aResult);
+		return $aResult;
+	}
+
+}
+

core/config.class.inc.php

@@ -809,6 +809,14 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		),
+		'transaction_storage' => array(
+			'type' => 'string',
+			'description' => 'The type of mechanism to use for storing the unique identifiers for transactions (Session|File).',
+			'default' => 'Session',
+			'value' => '',
+			'source_of_value' => '',
+			'show_in_conf_sample' => false,
+		),
 	);
 
 	public function IsProperty($sPropCode)