session 分布式

PHP在5.3提供了一个SessionHandler接口，可以自定义处理session的存储方案

通过该接口可以很容易的使用Redis进行分布式session处理，性能不会有太大问题，但对session提供了分布式存储的方案

<?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);

}