php实现的SESSION类

<?php
/
文件描述 Session类
=================================================================
文件名称 session.class.php
-----------------------------------------------------------------
适用环境 PHP5.2.x / mysql 5.0.x
-----------------------------------------------------------------
作 者 04ie。
-----------------------------------------------------------------
创建时间 2010-2-1
=================================================================
/
class Session
{
/
session默认有效时间
@aess public
@var ineger $_expiry
/
public $_expiry = 3600;
/
有效域名
@aess public
@var string $_domain
/
public $_domain = '.jb51.';
//初始化
public function __construct()
{
ini_set('session.use_trans_id', 0);
ini_set('session.gc_maxlifetime', $this->_expiry);
ini_set('session.use_cookie', 1);
ini_set('session.cookie_path', '/');
ini_set('session.cookie_domain', $this->_domain);
session_module_name('user');
session_set_save_handler(
array(&$this, 'open'),
array(&$this, 'close'),
array(&$this, 'read'),
array(&$this, 'write'),
array(&$this, 'destroy'),
array(&$this, 'gc')
);
session_start();
}
/
打开session
@aess public
@param string $savePath
@param string $sName
@return true
/
public function open($savePath, $sName)
{
$this->_conn = mysql_connect('localhost', 'root', '');
mysql_select_db('databases');
mysql_query('SET NAMES "utf8"');
return true;
}
/
关闭session
@aess public
@return bool
/
public function close()
{
return mysql_close($this->_conn);
}
/
读取session
@aess public
@param string $sid sessionID
@return mixed
/
public function read($sid)
{
$sql = "SELECT data FROM sessions WHERE sessionid='%s'";
$sql = sprintf($sql, $sid);
$res = mysql_query($sql, $this->_conn);
$row = mysql_fetch_assoc($res);
return !$row ? null : $row['data'];
}
/
写入session
@aess public
@param string $sid sessionID
@param string $data serialize序列化后的session内容
@return
/
public function write($sid, $data)
{
$expiry = time() + $this->_expiry;
$sql = "REPLACE INTO sessions (sessionid,expiratio
n,data) VALUES ('%s', '%d', '%s')";
$sql = sprintf($sql, $sid, $expiry, $data);
mysql_query($sql, $this->_conn);
return true;
}
/
销毁session
@aess public
@param string $sid sessionID
@return
/
public function destroy($sid)
{
$sql = "DELETE FROM sessions WHERE sessionid='%s'";
$sql = sprintf($sql, $sid);
mysql_query($sql, $this->_conn);
return true;
}
/
清理过期session
@aess public
@param integer $time
@return
/
public function gc($time = 0)
{
$sql = "DELETE FROM sessions WHERE expiration < '%d'";
$sql = sprintf($sql, time());
mysql_query($sql, $this->_conn);
mysql_query('OPTIMIZE TABLE sessions');
return true;
}