<?php 


class FileSessionHandler { 
    
    private $savePath;  
    //启动session
    function open($savePath, $sessionName) { 
        $this->savePath = $savePath; 
        if (!is_dir($this->savePath)) { 
            mkdir($this->savePath, 0777); 
        } 
        return true;
    } 
    
    //关闭session 
    function close() { 
        return true;
    } 
    
    //读取session 
    function read($id) { 
        return (string)@file_get_contents("$this->savePath/sess_$id"); 
    } 
    
    //写入session 
    function write($id, $data) { 
        return file_put_contents("$this->savePath/sess_$id", $data) === false ? false : true; 
    } 

    //销毁session 
    function destroy($id) { 
        $file = "$this->savePath/sess_$id"; 
        if (file_exists($file)) { 
            unlink($file); 
        } 
        return true; 
    } 

    //销毁session 
    function gc($maxlifetime) { 
        foreach (glob("$this->savePath/sess_*") as $file) { 
            if (filemtime($file) + $maxlifetime < time() && file_exists($file)) { 
                unlink($file); 
            } 
        } 
        return true; 
    } 

} 

$handler = new FileSessionHandler(); 

session_set_save_handler( 
    array($handler, 'open'), 
    array($handler, 'close'), 
    array($handler, 'read'), 
    array($handler, 'write'), 
    array($handler, 'destroy'), 
    array($handler, 'gc')
); 
// 下面这行代码可以防止使用对象作为会话保存管理器时可能引发的非预期行为
// 脚本执行完毕之后，内部会清除对象，有可能不调用 write 和 close 回调函数。
register_shutdown_function('session_write_close'); 
session_start(); 
// 现在可以使用 $_SESSION 保存以及获取数据了

<?php 

/** decrypt AES 256 
 * @param data $edata 
 * @param string $password 
 * @return decrypted data 
 */ 

function decrypt($edata, $password) { 
    $data = base64_decode($edata); 
    $salt = substr($data, 0, 16); 
    $ct = substr($data, 16); 
    $rounds = 3; 
    // depends on key length 
    $data00 = $password.$salt; 
    $hash = array(); 
    $hash[0] = hash('sha256', $data00, true); 
    $result = $hash[0]; 
    for ($i = 1; $i < $rounds; $i++) { 
        $hash[$i] = hash('sha256', $hash[$i - 1].$data00, true); 
        $result .= $hash[$i]; 
    } 
    $key = substr($result, 0, 32); 
    $iv = substr($result, 32,16); 
    return openssl_decrypt($ct, 'AES-256-CBC', $key, true, $iv); 
} 

/** 
 * crypt AES 256 
 * @param data $data
 * @param string $password
 * @return base64 encrypted data
 */
function encrypt($data, $password) { 
    // Set a random salt 
    $salt = openssl_random_pseudo_bytes(16); 
    $salted = ''; $dx = ''; 
    // Salt the key(32) and iv(16) = 48 
    while (strlen($salted) < 48) { 
        $dx = hash('sha256', $dx.$password.$salt, true); 
        $salted .= $dx; 
    } 
    $key = substr($salted, 0, 32); 
    $iv = substr($salted, 32,16); 
    $encrypted_data = openssl_encrypt($data, 'AES-256-CBC', $key, true, $iv); 
    return base64_encode($salt . $encrypted_data); 
} 


class EncryptedSessionHandler extends SessionHandler { 
    private $key; 
    
    public function __construct($key) { 
        $this->key = $key; 
    } 

    public function read($id) { 
        $data = parent::read($id); 
        if (!$data) { 
            return ""; 
        } else { 
            return decrypt($data, $this->key); 
        } 
    } 

    public function write($id, $data) { 
        $data = encrypt($data, $this->key); 
        return parent::write($id, $data); 
    } 
} 

ini_set('session.save_handler', 'files'); 
$key = 'secret_string'; 
$handler = new EncryptedSessionHandler($key); 
session_set_save_handler($handler, true); 
session_start();

//Database 
CREATE TABLE `Session` ( 
    `Session_Id` varchar(255) COLLATE utf8_unicode_ci NOT NULL,             
    `Session_Expires` datetime NOT NULL, 
    `Session_Data` text COLLATE utf8_unicode_ci, 
    PRIMARY KEY (`Session_Id`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; 
SELECT * FROM mydatabase.Session;

<?php 

class SysSession implements SessionHandlerInterface { 
    private $link; 
    //开启session 
    public function open($savePath, $sessionName) { 
        $link = mysqli_connect("server","user","pwd","mydatabase"); 
        if($link){ 
            $this->link = $link; 
            return true; 
        }else{ 
            return false; 
        } 
    } 

    //关闭session 
    public function close() { 
        mysqli_close($this->link); 
        return true; 
    } 

    //读取session 
    public function read($id) { 
        $sql = "SELECT Session_Data FROM Session WHERE Session_Id = '".$id."' AND Session_Expires > '".date('Y-m-d H:i:s')."'"; 
        $result = mysqli_query($this->link,$sql); 
        if($row = mysqli_fetch_assoc($result)){ 
            return $row['Session_Data']; 
        }else{ 
            return ""; 
        } 
    } 

    //写入session 
    public function write($id, $data) { 
        $DateTime = date('Y-m-d H:i:s'); 
        $NewDateTime = date('Y-m-d H:i:s',strtotime($DateTime.' + 1 hour')); 
        $sql = "REPLACE INTO Session SET Session_Id = '".$id."', Session_Expires = '".$NewDateTime."', Session_Data = '".$data."'"; 
        $result = mysqli_query($this->link,$sql ); 
        if($result){ 
            return true; 
        }else{ 
            return false; 
        } 
    } 

    //销毁session 
    public function destroy($id) { 
        $sql = "DELETE FROM Session WHERE Session_Id ='".$id."'"; 
        $result = mysqli_query($this->link,$sql); 
        if($result){ 
            return true; 
        }else{ 
            return false; 
        } 
    } 

    //回收session 
    public function gc($maxlifetime) { 
        $sql = "DELETE FROM Session WHERE ((UNIX_TIMESTAMP(Session_Expires) + ".$maxlifetime.") < ".$maxlifetime.")"; 
        $result = mysqli_query($this->link,$sql); 
        if($result){ 
            return true; 
        }else{ 
            return false; 
        } 
    } 

} 


$handler = new SysSession(); 
// 下面这行代码可以防止使用对象作为会话保存管理器时可能引发的非预期行为 
session_set_save_handler($handler, true);