source: trunk/include/functions_session.inc.php @ 1023

<?php
// +-----------------------------------------------------------------------+
// | PhpWebGallery - a PHP based picture gallery                           |
// | Copyright (C) 2002-2003 Pierrick LE GALL - pierrick@phpwebgallery.net |
// | Copyright (C) 2003-2005 PhpWebGallery Team - http://phpwebgallery.net |
// +-----------------------------------------------------------------------+
// | branch        : BSF (Best So Far)
// | file          : $RCSfile$
// | last update   : $Date: 2006-02-03 16:19:56 +0000 (Fri, 03 Feb 2006) $
// | last modifier : $Author: nikrou $
// | revision      : $Revision: 1023 $
// +-----------------------------------------------------------------------+
// | This program is free software; you can redistribute it and/or modify  |
// | it under the terms of the GNU General Public License as published by  |
// | the Free Software Foundation                                          |
// |                                                                       |
// | This program is distributed in the hope that it will be useful, but   |
// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
// | General Public License for more details.                              |
// |                                                                       |
// | You should have received a copy of the GNU General Public License     |
// | along with this program; if not, write to the Free Software           |
// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
// | USA.                                                                  |
// +-----------------------------------------------------------------------+

// The function generate_key creates a string with pseudo random characters.
// the size of the string depends on the $conf['session_id_size'].
// Characters used are a-z A-Z and numerical values. Examples :
//                    "Er4Tgh6", "Rrp08P", "54gj"
// input  : none (using global variable)
// output : $key
function generate_key($size)
{
  global $conf;

  $md5 = md5(substr(microtime(), 2, 6));
  $init = '';
  for ( $i = 0; $i < strlen( $md5 ); $i++ )
  {
    if ( is_numeric( $md5[$i] ) ) $init.= $md5[$i];
  }
  $init = substr( $init, 0, 8 );
  mt_srand( $init );
  $key = '';
  for ( $i = 0; $i < $size; $i++ )
  {
    $c = mt_rand( 0, 2 );
    if ( $c == 0 )      $key .= chr( mt_rand( 65, 90 ) );
    else if ( $c == 1 ) $key .= chr( mt_rand( 97, 122 ) );
    else                $key .= mt_rand( 0, 9 );
  }
  return $key;
}

if (isset($conf['session_save_handler']) 
  and ($conf['session_save_handler'] == 'db')
  and defined('PHPWG_INSTALLED')) 
{
  session_set_save_handler('pwg_session_open', 
    'pwg_session_close',
    'pwg_session_read',
    'pwg_session_write',
    'pwg_session_destroy',
    'pwg_session_gc'
  );
  ini_set('session.use_cookies', $conf['session_use_cookies']);
  ini_set('session.use_only_cookies', $conf['session_use_only_cookies']);
  ini_set('session.use_trans_sid', intval($conf['session_use_trans_sid']));
  ini_set('session.name', $conf['session_name']);
  ini_set('session.cookie_path', dirname($_SERVER['PHP_SELF']));
}

/**
 * returns true; used when the session_start() function is called
 *
 * @params not use but useful for php engine
 */
function pwg_session_open($path, $name) 
{
  return true;
}

/**
 * returns true; used when the session is closed (unset($_SESSION))
 *
 */
function pwg_session_close() 
{
  pwg_session_gc();
  return true;
}

/**
 * this function returns
 * a string corresponding to the value of the variable save in the session 
 * or an empty string when the variable doesn't exist
 * 
 * @param string session id
 */
function pwg_session_read($session_id) 
{
  $query = '
SELECT data 
  FROM '.SESSIONS_TABLE.'
  WHERE id = \''.$session_id.'\'
;';
  $result = pwg_query($query);
  if ($result) 
  {
    $row = mysql_fetch_assoc($result);
    return $row['data'];
  } 
  else 
  {
    return '';
  }
}

/**
 * returns true; writes set a variable in the active session 
 * 
 * @param string session id
 * @data string value of date to be saved
 */
function pwg_session_write($session_id, $data) 
{
  $query = '
SELECT id 
  FROM '.SESSIONS_TABLE.'
  WHERE id = \''.$session_id.'\'
;';
  $result = pwg_query($query);
  if (mysql_num_rows($result)) 
  {
    $query = '
UPDATE '.SESSIONS_TABLE.' 
  SET expiration = now()
  WHERE id = \''.$session_id.'\'
;';    
    pwg_query($query);
  } 
  else 
  {
    $query = '
INSERT INTO '.SESSIONS_TABLE.' 
  (id,data,expiration)
  VALUES(\''.$session_id.'\',\''.$data.'\',now())
;';
    pwg_query($query);    
  }
  return true;
}

/**
 * returns true; delete the active session 
 * 
 * @param string session id
 */
function pwg_session_destroy($session_id) 
{
  $query = '
DELETE 
  FROM '.SESSIONS_TABLE.'
  WHERE id = \''.$session_id.'\'
;';
  pwg_query($query);
  return true;
}

/**
 * returns true; delete expired sessions
 * called each time a session is closed.
 */
function pwg_session_gc() 
{
  global $conf;

  $query = '
DELETE 
  FROM '.SESSIONS_TABLE.'
  WHERE UNIX_TIMESTAMP(NOW()) - UNIX_TIMESTAMP(expiration) > '
  .$conf['session_length'].'
;';
  pwg_query($query);
  return true;
}
?>