class.Obfuscator.php

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<?php
/**
 * wCMF - wemove Content Management Framework
 * Copyright (C) 2005-2014 wemove digital solutions GmbH
 *
 * Licensed under the terms of any of the following licenses 
 * at your choice:
 *
 * - GNU Lesser General Public License (LGPL)
 *   http://www.gnu.org/licenses/lgpl.html
 * - Eclipse Public License (EPL)
 *   http://www.eclipse.org/org/documents/epl-v10.php
 *
 * See the license.txt file distributed with this work for 
 * additional information.
 *
 * $Id: class.Obfuscator.php 1462 2014-02-04 23:52:27Z iherwig $
 */
require_once(BASE."wcmf/lib/util/class.SessionData.php");

/**
 * @class Obfuscator
 * @ingroup Util
 * @brief This class allows to obfuscate strings. By passing an objuscated string
 * to the method Obfuscator::unveil() the orginal string is returned. 
 * This is especially useful, if you want to place a secret string inside a client view
 * as a parameter and want to get the original string back as the request is processed.
 *
 * @author      ingo herwig <ingo@wemove.com>
 */
class Obfuscator
{
  // session name constants
  var $VALUES_VARNAME = 'Obfuscator.values';
  
  /**
   * Returns an instance of the class.
   * @return A reference to the only instance of the Singleton object
   */  
  function &getInstance()
  {
    global $gObfuscator;

    if ($gObfuscator == null)
      $gObfuscator = new Obfuscator();

    return $gObfuscator;
  }
  /**
   * Get an obfuscated string
   * @note This method maybe called staticly
   * @param str The original sring
   * @return The obfuscated string
   */
  function obfuscate($str)
  {
    if (strlen($str) == 0)
      return '';
      
    $obfuscator = &Obfuscator::getInstance();
    $session = &SessionData::getInstance();
    $obfuscator->ensureStorage();
    
    // create and store the value
    $obfuscated = md5($str);
    $values = $session->get($obfuscator->VALUES_VARNAME);
    $values[$obfuscated] = $str;
    $session->set($obfuscator->VALUES_VARNAME, $values);
    
    return $obfuscated;
  }
  /**
   * Get an unveiled string
   * @note This method maybe called staticly
   * @param str The obfuscated sring
   * @return The original string or an empty string if it does not exist
   */
  function unveil($str)
  {
    $obfuscator = &Obfuscator::getInstance();
    $session = &SessionData::getInstance();
    $obfuscator->ensureStorage();
    
    $values = $session->get($obfuscator->VALUES_VARNAME);
    $unveiled = $values[$str];
    return $unveiled;
  }
  /**
   * Ensure that the session storage for the values is initialized
   */ 
  function ensureStorage()
  {
    $session = &SessionData::getInstance();
    if (!$session->exist($obfuscator->VALUES_VARNAME))
    {
      $values = array();
      $session->set($obfuscator->VALUES_VARNAME, $values);
    }
  }
}