lib/AkDbSession.php

   1 <?php
   2 /* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
   3
   4 // +----------------------------------------------------------------------+
   5 // | Akelos Framework - http://www.akelos.org                             |
   6 // +----------------------------------------------------------------------+
   7 // | Copyright (c) 2002-2006, Akelos Media, S.L.  & Bermi Ferrer Martinez |
   8 // | Released under the GNU Lesser General Public License, see LICENSE.txt|
   9 // +----------------------------------------------------------------------+
  10
  11 /**
  12  * @package ActionController
  13  * @subpackage Sessions
  14  * @author Bermi Ferrer <bermi a.t akelos c.om>
  15  * @copyright Copyright (c) 2002-2006, Akelos Media, S.L. http://www.akelos.org
  16  * @license GNU Lesser General Public License <http://www.gnu.org/copyleft/lesser.html>
  17  */
  18
  19 if(!defined('AK_DBSESSION_CLASS_INCLUDED')){ define('AK_DBSESSION_CLASS_INCLUDED',true); // Class overriding trick
  20
  21
  22 require_once(AK_LIB_DIR.DS.'Ak.php');
  23 require_once(AK_LIB_DIR.DS.'AkObject.php');
  24
  25
  26 /**
  27 * Database based session.
  28 *
  29 * This class enables saving sessions into a database. This can
  30 * be usefull for multiple server sites, and to have more
  31 * control over sessions.
  32 *
  33 * <code>
  34 *
  35 * require_once(AK_LIB_DIR.'/AkDbSession.php');
  36 *
  37 * $AkDbSession = new AkDbSession();
  38 * $AkDbSession->sessionLife = AK_SESSION_EXPIRE;
  39 * session_set_save_handler (
  40 * array(&$AkDbSession, '_open'),
  41 * array(&$AkDbSession, '_close'),
  42 * array(&$AkDbSession, '_read'),
  43 * array(&$AkDbSession, '_write'),
  44 * array(&$AkDbSession, '_destroy'),
  45 * array(&$AkDbSession, '_gc')
  46 * );
  47 *
  48 * </code>
  49 *
  50 * @author Bermi Ferrer <bermi at akelos com>
  51 * @copyright Copyright (c) 2002-2005, Akelos Media, S.L. http://www.akelos.org
  52 * @license GNU Lesser General Public License <http://www.gnu.org/copyleft/lesser.html>
  53 * @since 0.1
  54 * @version $Revision 0.1 $
  55 */
  56 class AkDbSession extends AkObject
  57 {
  58     /**
  59     * Secconds for the session to expire.
  60     *
  61     * @see setSessionLife
  62     * @access public
  63     * @var integer $sessionLife
  64     */
  65     var $sessionLife = AK_SESSION_EXPIRE;
  66
  67     /**
  68     * Database instance handler
  69     *
  70     * Stores a reference to an ADODB database instance.
  71     *
  72     * @access protected
  73     * @var object $_db
  74     */
  75     var $_db;
  76
  77     /**
  78     * Original session value for avoiding hitting the database in case nothing has changed
  79     *
  80     * @access private
  81     * @var string $_db
  82     */
  83     var $_original_sess_value = '';
  84
  85     /**
  86     * $this->sessionLife setter
  87     *
  88     * Use this method to set $this->sessionLife value
  89     *
  90     * @access public
  91     * @see get$sessionLife
  92     * @param    integer    $sessionLife    Secconds for the session to expire.
  93     * @return bool Returns true if $this->sessionLife has been set
  94     * correctly.
  95     */
  96     function setSessionLife($sessionLife)
  97     {
  98         $this->sessionLife = $sessionLife;
  99
 100     }
 101
 102     // ---- Protected methods ---- //
 103
 104     /**
 105     * Session open handler
 106     *
 107     * @access protected
 108     * @return boolean
 109     */
 110     function _open()
 111     {
 112         $this->_db =& Ak::db();
 113         return true;
 114     }
 115
 116     /**
 117     * Session close handler
 118     *
 119     * @access protected
 120     * @return boolean
 121     */
 122     function _close()
 123     {
 124         /**
 125         * @todo Get from cached vars last time garbage collection was made to avoid hitting db
 126         * on every request
 127         */
 128         $this->_gc();
 129         return true;
 130     }
 131
 132     /**
 133     * Session read handler
 134     *
 135     * @access protected
 136     * @param    string    $id    Session Id
 137     * @return string
 138     */
 139     function _read($id)
 140     {
 141         $result = $this->_db->selectValue("SELECT value FROM sessions WHERE id = ".$this->_db->quote_string($id));
 142         return is_null($result) ? '' : (string)$result;
 143     }
 144
 145     /**
 146     * Session write handler
 147     *
 148     * @access protected
 149     * @param    string    $id
 150     * @param    string    $data
 151     * @return boolean
 152     */
 153     function _write($id, $data)
 154     {
 155         // We don't want to hit the db if nothing has changed
 156         if($this->_original_sess_value != $data){
 157             /**
 158             * @todo replace with dbAdapter-method
 159             */
 160             $ret = $this->_db->connection->Replace('sessions', array('id'=>$this->_db->quote_string($id),'expire'=>$this->_db->quote_datetime(time()),'value'=>$this->_db->quote_string($data)), 'id');
 161             if($ret == 0){
 162                 return false;
 163             }else{
 164                 return true;
 165             }
 166         }else {
 167             return true;
 168         }
 169     }
 170
 171     /**
 172     * Session destroy handler
 173     *
 174     * @access protected
 175     * @param    string    $id
 176     * @return boolean
 177     */
 178     function _destroy($id)
 179     {
 180         return (bool)$this->_db->delete('DELETE FROM sessions WHERE id = '.$this->_db->quote_string($id));
 181         }
 182
 183     /**
 184     * Session garbage collection handler
 185     *
 186     * @access protected
 187     * @return boolean
 188     */
 189     function _gc()
 190     {
 191         return (bool)$this->_db->delete('DELETE FROM sessions WHERE expire < '.$this->_db->quote_datetime(time()-$this->sessionLife));
 192         }
 193
 194
 195 }
 196
 197 }// End of if(!defined('AK_DBSESSION_CLASS_INCLUDED')){
 198
 199 ?>