PHP 使用MySQL管理Session的回调函数详解

<?php
 class mysession extends dbsql {

  /**
   * __construct()
   */
  public function __construct() {
   parent::__construct ();

  }

  /**
   * open()
   *
   * @param <string> $ssavepath
   * @param <string>$ssessionnames
   *
   * @return <boolean> true
   */
  public function open($ssavepath, $ssessionname) {
   return true;
  }

  /**
   * close()
   */
  public function close() {
   return true;
  }

  /**
   * read()
   *
   * @param <string> $ssessionid
   * @return <string> session data or null on error...
   */
  public function read($ssessionid) {
   $ssessionid = addslashes(trim($ssessionid));
   $ssql = "select * from tb_session where f_sessionid = '{$ssessionid}'";
   //echo $ssql;
   if(false != ($result = $this->select($ssql))) {
    //var_dump($result[0]['f_sessiondata']);
    return $result[0]['f_sessiondata'];
   } else {
    return '';
   }
  }

  /**
   * write()
   *
   * @param <string> $sessionid
   * @param <string> $ssessiondata
   *
   * @return <boolean> true or false
   */
  public function write($ssessionid, $ssessiondata) {
   $arrsession = array();
   $arrsession['f_sessionid'] = addslashes(trim($ssessionid));
   $arrsession['f_sessiondata'] = addslashes($ssessiondata);
   $arrsession['f_sessioncreated'] = date("y-m-d h:i:s");
   $arrsession['f_sessionupdated'] = date("y-m-d h:i:s", time() + 1440);

   // 新session及更新的session
   if (false != ($result = $this->insertdata('tb_session', $arrsession))) {
    return true;
   } else {
    $arrupdatesession = array();
    $arrupdatesession['f_sessiondata'] = addslashes($ssessiondata);
    $arrupdatesession['f_sessionupdated'] = date("y-m-d h:i:s", time() + 1440);
    if (false != ($result = $this->updatedata('tb_session', "'".addslashes($ssessionid)."'", 'f_sessionid', $arrupdatesession))) {
     return true;
    } else {
     return false;
    }
   }
  }

  /**
   * destroy()
   *
   * @param <string> $ssessionid
   * @return <boolean> true
   */
  public function destroy($ssessionid) {
   $ssessionid = addslashes(trim($ssessionid));
   $this->deldata($ssessionid, 'f_sessionid', 'tb_session');
   return true;
  }

  /**
   * gc
   *
   * @param <int> $nmaxlifetime seconds
   *
   * @return <boolean> true
   */
  public function gc($nmaxlifetime) {
   $dtexpiredtime = date("y-m-d h:i:s", time() - $nmaxlifetime);

   $ssql = "delete from tb_session where f_sessionupdated < {$dtexpiredtime}";
   //echo $ssql;
   $this->delete($ssql);

   return true;
  }
  /**
   * __desctruct()
   *
   */
  function __destruct() {
   // ensure session data is written out before classes are destroyed
      // (see http://bugs.php.net/bug.php?id=33772 for details)
         @session_write_close();
     } // __destruct
 }
?>