PHP 使用redis实现Session功能的方法

对于大访问量的站点使用php系统默认的Session 速度不够快，优化方法为将其存入数据库、或者使用Redis KEY-VALUE数据存储方案

首先新建一个ownsession表

CREATE TABLE `ownsession` (
  `sid`        CHAR(40)     NOT NULL,
  `updatetime` INT(20)      NOT NULL,
  `data`       VARCHAR(200) NOT NULL,
  UNIQUE KEY `sid` (`sid`) USING HASH
)
  ENGINE = MEMORY
  DEFAULT CHARSET = utf8;

Mysql 的memory引擎采用内存表，所有数据存储在内存，操作速度快

数据库操作文件 db.php

//数据库代码 db.php

class Database
{
    static $instance;
    static $db;

    static function getInstance()
    {
        if (self::$instance) {
            return self::$instance;
        } else {
            return new Database();
        }
    }

    public function __construct()
    {
        self::$db = new PDO('mysql:host=127.0..1;dbname=session', 'root', '');
    }

    public function getOne($sql)
    {
        $rs = self::$db->query($sql);
        @$rs->setFetchMode(PDO::FETCH_ASSOC);//返回关联数组
        $result = $rs->fetch();
        return $result;
    }

    public function execute($sql)
    {
        $rs = self::$db->exec($sql);
        return $rs;
    }
}

$data = Database::getInstance();

自定义session操作

//引入数据库文件
include "db.php";

class MySessionHandler implements SessionHandlerInterface
{
    private $savePath;
    private $sessData;
    public $expiretime;  //设置过期时间
    public $db;  //数据库

    public function __construct($hanlder = '')
    {
        $this->db = Database::getInstance(); //获取数据库实力
        //var_dump($this->db);
    }

    public function open($savePath, $sessionName)
    {
        return true;
    }

    public function close()
    {
        return true;
    }

    public function read($id)
    {
        $sql = "select * from sessions where sid ='$id'";
        $result = $this->db->execute($sql);
        if (!empty($result)) {
            return $this->sessData = $result;
        }
    }

    /**
     * @param String $id   当前会话ID
     * @param String $data 序列化之后的字符串
     * @return Boolean
     */
    public function write($id, $data)
    {
        // echo $id;    // echo $data;
        $now = time();
        $newExp = $now + $this->expiretime;  //总时间=当前时间 + 期限时间
        $sql = "select * from sessions where sid ='$id'";
        $result = $this->db->getOne($sql);    //var_dump($result);
        if ($data == '' || isset($data)) {
            $data = $this->sessData;
        }
        if ($result) {
            //如果存在则更新
            $sql = "update sessions set updatetime = '$newExp',data ='$data' where sid = '$id'";
            //echo $sql;
            $update_data = $this->db->execute($sql);
            if ($update_data) {
                return true;
            }
        } else {
            //不存在则生成生成
            $sql = "insert into sessions(sid,updatetime,data) values('$id','$now','$data')";
            $insert_data = $this->db->execute($sql);
            if ($insert_data) {
                return true;
            }
        }
        return false;
    }

    public function destroy($id)
    {
        //销毁
        $sql = "delete from sessions where sid=" . "$id";
        $destory = $this->db->execute($sql);
        if ($destory) {
            return true;
        } else {
            return false;
        }
    }

    public function gc($sessMaxLifeTime)
    {
        $t = time();
        $sql = "delete from sessions where $t - 'updatetime'>${sessMaxLifeTime}";
        $data = $this->db->execute($sql);
        if ($data) {
            return true;
        } else {
            return false;
        }
        return true;
    }
}

实例化

此处 PHP 手册可以有两种方法

    1，实现了SessionHandlerInterface借口的对象,自PHP5.4可以使用

    2 ，直接使用  session_set_save_handler

//判断PHP版本
if (version_compare(PHP_VERSION, 5.4) == 1) {
    session_set_save_handler($handler, true);
    session_start();
} else {
    ini_set('session.use_trans_sid', 0);
    ini_set('session.use_cookies', 1);
    ini_set('session.cookie_path', '/');
    ini_set('session.save_handler', 'user');
    session_module_name('user');
    session_set_save_handler(
        array($session, "open"),
        array($session, "close"),
        array($session, "read"),
        array($session, "write"),
        array($session, "destory"),
        array($session, "gc")
    );
    session_start();
}

使用REDIS 存储SESSION

class SessionManager
{
    private $redis;
    private $sessionSavePath;
    private $sessionName;
    private $sessionExpireTime = 30;

    public function __construct()
    {
        $this->redis = new Redis();
        $this->redis->connect('127.0.0.1', 6379);  //连接redis
        session_set_save_handler(
            array($this, "open"),
            array($this, "close"),
            array($this, "read"),
            array($this, "write"),
            array($this, "destory"),
            array($this, "gc")
        );
        session_start();
    }

    public function open($path, $name)
    {
        return true;
    }

    public function close()
    {
        return true;
    }

    public function read($id)
    {
        $value = $this->redis->get($id);
        if ($value) {
            return $value;
        } else {
            return "";
        }
    }

    public function write($id, $data)
    {
        if ($this->redis->set($id, $data)) {
            $this->redis->expire($id, $this->sessionExpireTime);          //设置过期时间
            return true;
        }
        return false;
    }

    public function destory($id)
    {
        if ($this->redis->delete($id)) {
            return true;
        }
        return false;
    }

    public function gc($maxlifetime)
    {
        return true;
    }

    //析构函数
    public function __destruct()
    {
        session_write_close();
    }
}

$re = new SessionManager();
$_SESSION['name'] = "aa";
echo $_SESSION['name'];

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