php 实现自定义session存储方式

<?php
class RedisSessionHandler implements SessionHandlerInterface{
private $redis;
private $config;
private $namespace;
private $session_id = null;
private $maxlifetime = null;

public function __construct($namespace,$host,$port) {
//初始化redis
$this->config = array(
'host'=>$host,
'port'=>$port
);
$this->redis = new Redis();
$this->redis->connect($this->config['host'],$this->config['port']);
//设置当前的sessionid生成的命名空间
$this->namespace = $namespace;
//设置初始化的session_id
$session_name = ini_get("session.name");
//没有设置过session，新的会话，需要重新生成sessionid
if ( empty($_COOKIE[$session_name]) ) {
$this->session_id = true;
}
}
public function open($savePath, $sessionName){
$connect = $this->redis->connect($this->config['host'],$this->config['port']);
if(!$connect) return false;
//在初次设置的时候，重设PHP本身的session_id并判断session_id是否已经存在
$id = session_id();
if($this->session_id && $this->session_id != $id){
do{
$this->session_id = $this->session_id();
}while($this->redis->exists($this->namespace.'@'.$this->session_id));
session_id($this->session_id);
}
//设置生成周期
$this->maxlifetime = ini_get("session.gc_maxlifetime");
return true;
}
public function close(){
$this->redis->close();
return true;
}
public function read($id){
return $this->redis->get($this->namespace.'@'.$id);
}
public function write($id, $data){
return $this->redis->setex($this->namespace.'@'.$id,$this->maxlifetime,$data);
}
public function destroy($id){
$this->redis->delete($this->namespace.'@'.$id);
return true;
}
public function gc($maxlifetime){
return true;
}
/**
* 生成guid
*/
private function session_id(){
$uid = uniqid("", true);
$data = $this->namespace;
$data .= $_SERVER['REQUEST_TIME'];
$data .= $_SERVER['HTTP_USER_AGENT'];
$data .= $_SERVER['SERVER_ADDR'];
$data .= $_SERVER['SERVER_PORT'];
$data .= $_SERVER['REMOTE_ADDR'];
$data .= $_SERVER['REMOTE_PORT'];
$hash = strtoupper(hash('ripemd128', $uid . md5($data)));
return substr($hash,0,32);
}
}
$param = array(
"namespace"=>'',
"redis_host"=>'127.0.0.1',
"redis_port"=>'6379'
);
if($param){
$handler = new RedisSessionHandler($param['namespace'],$param['redis_host'],$param['redis_port']);
session_set_save_handler($handler, true);
}