php负载中使用redis实现session会话保持

session.save_handler = redis
session.save_path = "tcp://172.16.1.51:6379"
//session.save_path = "tcp://172.16.1.51:6379?auth=123123"如果redis配置的密码需要写成这种方式，填写redis的密码
session.auto_start = 1

;php_value[session.save_handler] = files
;php_value[session.save_path]    = /var/lib/php/session

ini_set("session.save_handler","redis");
ini_set("session.save_path","tcp://172.16.1.51:6379");
//如果redis设置了密码需要改下面一句为
//ini_set("session.save_path","tcp://172.16.1.51:6379?auth=123123");

<?php
//ini_set("session.save_handler", "redis");
//ini_set("session.save_path", "tcp://172.16.1.51:6379?auth=123123");

session_start();

//存入session
$_SESSION['class'] = array('name' => 'toefl', 'num' => 8);

//连接redis
$redis = new redis();
$redis->connect('127.0.0.1', 6379);

//检查session_id
echo 'session_id:' . session_id() . '<br/>';

//redis存入的session（redis用session_id作为key,以string的形式存储）
echo 'redis_session:' . $redis->get('PHPREDIS_SESSION:' . session_id()) . '<br/>';

//php获取session值
echo 'php_session:' . json_encode($_SESSION['class']);

<?php
class redisSession{
    /**
     * 保存session的数据库表的信息
     */
    private $_options = array(
        'handler' => null, //数据库连接句柄
        'host' => null,
        'port' => null,
        'lifeTime' => null,
        'prefix'   => 'PHPREDIS_SESSION:'
    );

    /**
     * 构造函数
     * @param $options 设置信息数组
     */
    public function __construct($options=array()){
        if(!class_exists("redis", false)){
            die("必须安装redis扩展");
        }
        if(!isset($options['lifeTime']) || $options['lifeTime'] <= 0){
            $options['lifeTime'] = ini_get('session.gc_maxlifetime');
        }
        $this->_options = array_merge($this->_options, $options);
    }

    /**
     * 开始使用该驱动的session
     */
    public function begin(){
        if($this->_options['host'] === null ||
           $this->_options['port'] === null ||
           $this->_options['lifeTime'] === null
        ){
            return false;
        }
        //设置session处理函数
        session_set_save_handler(
            array($this, 'open'),
            array($this, 'close'),
            array($this, 'read'),
            array($this, 'write'),
            array($this, 'destory'),
            array($this, 'gc')
        );
    }
    /**
     * 自动开始回话或者session_start()开始回话后第一个调用的函数
     * 类似于构造函数的作用
     * @param $savePath 默认的保存路径
     * @param $sessionName 默认的参数名，PHPSESSID
     */
    public function open($savePath, $sessionName){
        if(is_resource($this->_options['handler'])) return true;
        //连接redis
        $redisHandle = new Redis();
        $redisHandle->connect($this->_options['host'], $this->_options['port']);
        if(!$redisHandle){
            return false;
        }

        $this->_options['handler'] = $redisHandle;
//        $this->gc(null);
        return true;

    }

    /**
     * 类似于析构函数，在write之后调用或者session_write_close()函数之后调用
     */
    public function close(){
        return $this->_options['handler']->close();
    }

    /**
     * 读取session信息
     * @param $sessionId 通过该Id唯一确定对应的session数据
     * @return session信息/空串
     */
    public function read($sessionId){
        $sessionId = $this->_options['prefix'].$sessionId; 
        return $this->_options['handler']->get($sessionId);
    }

    /**
     * 写入或者修改session数据
     * @param $sessionId 要写入数据的session对应的id
     * @param $sessionData 要写入的数据，已经序列化过了
     */
    public function write($sessionId, $sessionData){
        $sessionId = $this->_options['prefix'].$sessionId; 
        return $this->_options['handler']->setex($sessionId, $this->_options['lifeTime'], $sessionData);
    }

    /**
     * 主动销毁session会话
     * @param $sessionId 要销毁的会话的唯一id
     */
    public function destory($sessionId){
        $sessionId = $this->_options['prefix'].$sessionId; 
//        $array = $this->print_stack_trace();
//        log::write($array);
        return $this->_options['handler']->delete($sessionId) >= 1 ? true : false;
    }

    /**
     * 清理绘画中的过期数据
     * @param 有效期
     */
    public function gc($lifeTime){
        //获取所有sessionid，让过期的释放掉
        //$this->_options['handler']->keys("*");
        return true;
    }
    //打印堆栈信息
    public function print_stack_trace()
    {
        $array = debug_backtrace ();
        //截取用户信息
        $var = $this->read(session_id());
        $s = strpos($var, "index_dk_user|");
        $e = strpos($var, "}authId|");
        $user = substr($var,$s+14,$e-13);
        $user = unserialize($user);
        //print_r($array);//信息很齐全
        unset ( $array [0] );
        if(!empty($user)){
          $traceInfo = $user['id'].'|'.$user['user_name'].'|'.$user['user_phone'].'|'.$user['presona_name'].'++++++++++++++++\n';
        }else{
          $traceInfo = '++++++++++++++++\n';
        }
        $time = date ( "y-m-d H:i:m" );
        foreach ( $array as $t ) {
            $traceInfo .= '[' . $time . '] ' . $t ['file'] . ' (' . $t ['line'] . ') ';
            $traceInfo .= $t ['class'] . $t ['type'] . $t ['function'] . '(';
            $traceInfo .= implode ( ', ', $t ['args'] );
            $traceInfo .= ")\n";
        }
        $traceInfo .= '++++++++++++++++';
        return $traceInfo;
            }
    }

在你的项目入口处调用上边的类：上边的方法等于是重写了session写入文件的方法，将数据写入到了Redis中。
初始化文件 init.php

<?php
require_once("redisSession.php");
$handler = new redisSession(array(
'host' => "172.16.1.51",
'port' => "6379"
));
$handler->begin();
// 这也是必须的，打开session，必须在session_set_save_handler后面执行
session_start();

测试 test.php
```php
<?php
// 引入初始化文件
include("init.php");
$_SESSION['isex'] = "Hello";  
$_SESSION['sex']  = "Corwien";

// 打印文件
print_r($_SESSION);
// ( [sex] => Corwien [isex] => Hello )

172.16.1.51:6379> keys *
 1) "first_key"
 2) "mylist"
 3) "language"
 4) "mytest"
 5) "pragmmer"
 6) "good"
 7) "PHPREDIS_SESSION:29a111bcs120sv48ibmmjqdag4"
 8) "user:1"
 9) "counter:__rand_int__"
10) "key:__rand_int__"
11) "tutorial-list"
12) "id:1"
13) "name"
127.0.0.1:6379> get PHPREDIS_SESSION:29a111bcs120sv48ibmmjqdag4
"sex|s:7:\"Corwien\";isex|s:5:\"Hello\";"
127.0.0.1:6379>