优化使用mysql存储session

12/20/2008来源:PHP技巧人气:6102

之前写过两篇文章《自定义session(二)——数据库保存》和《我为什么不使用session》
  但后来发现都有问题。前者处理在实际中几乎没什么用处,而且session回收还得自己另外处理。后者频繁的操作数据库,打来了很大的性能问题。

  这两天仔细考虑下,大致给出一个方案,但还没有具体详细的测试。
  1、session处理和统计结合起来。同时游客也都有记录。
  2、完全使用数据库和cookie来模拟session的功能。
  3、用户的对session的操作都尽量保证在一条sql语句完成。不用到session的时候,绝对不多一条查询。
  4、为了效率起见,session的回收没有集成进来,但提供了接口,可以调用实现。

暂时给出代码,不具体解释。
sql

 

CREATE TABLE `*****_session` (
 `sid` char(32) NOT NULL,
 `uid` int(10) NOT NULL,
 `username` char(32) NOT NULL,
 `usertype` tinyint(1) NOT NULL,
 `activetime` int(10) NOT NULL,
 `expiry` int(10) NOT NULL,
 `ip` char(15) NOT NULL,
 `url` char(80) NOT NULL,
 `value` char(255) NOT NULL,
 PRIMARY KEY  (`sid`)
) ENGINE=MEMORY DEFAULT CHARSET=utf8;

 


php代码


<?
class session{
   
    private $_sessionPrex= '';//session的前缀
   
    private $_time = '';//当前时间
   
    private $_model = null;//数据库操作模型
   
    private $_expiry = 1200;//session有效时间
   
    private $_domain = '';//session的作用域
   
    protected $isNew = 0;//判定操作动作 0 更新 1 增加
   
    protected $session = array();//对应的一条session记录
   
    public function __construct($options){
        $this->_setOptions($options);
        if(empty($this->_time))$this->_time = time();
        $this->session['activetime'] = $this->_time;
    }
   
    public function start(){
        $this->_getSid();
    }
   
    public function set($key,$value){
        if(in_array($key,array('uid','username','usertype','url','expiry'))){
            if($key == 'expiry'){
                $this->_setCookie($this->_sessionPrex.'_sid',$this->session['sid'],$value);
                $this->_setCookie($this->_sessionPrex.'_uid',$this->session['uid'],$value);
            }
            $this->session[$key] = $value;
        }else{
            $other = $this->session['value'];
            $other[$key] = $value;
            $this->session['value'] = $other;
        }
    }
   
    public function get($key){
        if(in_array($key,array('uid','username','usertype','url','expiry'))){
            return $this->session[$key];
        }else{
            if(isset($this->session['value'][$key])){
                return $this->session['value'][$key];
            }
            return null;
        }
    }
   
    public function gc($file,$time = 1200){
        $lasttime = file_get_contents($file);
        if($lasttime + $time<$this->_time){
            file_put_contents($file,$this->_time);
            return $this->_model->delete('activetime+expiry<'.$this->_time);
        }
    }
   
    public function destroy(){
        $this->session['uid'] = 0;
        $this->session['username'] = '';
        $this->session['usertype'] = -1;
        $this->session['expiry'] = $this->_expiry;
        $this->session['value'] = array();
        $this->_setCookie($this->_sessionPrex.'_sid',$this->session['sid'],$this->_expiry);
        $this->_setCookie($this->_sessionPrex.'_uid',$this->session['uid'],$this->_expiry);
    }
   
    public function __destruct(){
        $this->_save();
    }
   
    private function _save(){
        $dbSession = $this->session;
        $dbSession['value'] = serialize($dbSession['value']);
        if(strlen($dbSession['value'])>255)$this->_error('session->value is too long!');
        if($this->isNew == 1){
            //增加
            $this->_model->insert($dbSession);
        }else{
            //更新
            $sid = $dbSession['sid'];
            $this->_model->update(array_slice($dbSession,1),'sid=\''.$sid.'\'');
        }
    }
   
    private function _getSession($sid){
        $dbSession = $this->_model->detail('sid = \''.$sid.'\'');
        if(!$dbSession)return false;
        $dbSession['value'] = unserialize($dbSession['value']);
        $this->session = array_merge($dbSession,$this->session);       
        return true;
    }
   
    private function _getSid(){
        $sid = strip_tags($_COOKIE[$this->_sessionPrex.'_sid']);
        if(strlen($sid)==32){
            if($this->_getSession($sid)){
                return true;
            }
        }else{
            $sid = md5(time().mt_rand(1000,10000));
            $this->_setCookie($this->_sessionPrex.'_sid',$sid);
        }
        $this->_setCookie($this->_sessionPrex.'_uid',0);
        $this->session = array(
                'uid' => 0,
                'username' => '',
                'usertype' => -1,
                'activetime' => $this->_time,
                'ip' => $this->_getip(),
                'url' => strip_tags($_SERVER['REQUEST_URI']),
                'expiry' =>$this->_expiry,
                'value' => array()
        );
        $this->isNew = 1;
        $this->session['sid'] = $sid;
    }
   
    private function _setCookie($name,$value,$expiry=0){
        if(empty($expiry))$expiry = $this->_expiry;
        if(empty($this->_domain)){
            setcookie($name,$value,$this->_time + $expiry,'/');
        }else{
            setcookie($name,$value,$this->_time + $expiry,'/',$this->_domain);
        }
    }
   
    private function _getip(){
        return getip();
    }
   
    private function _setOptions($options){
        foreach ($options as $key=>$value){
            if(in_array($key,array('sessionPrex','time','model','expiry','domain'))){
                $key = '_'.$key;
                $this->$key = $value;
            }
        }
    }
   
    private function _error($msg){
        throw new Phpbean_Exception($msg);
    }
}
?>


(注意,该代码不能直接使用,本文主要是提供一种思路)