Session技术笔记

小风
2016-05-25 15:15:15
PHP
PHP
8149

session执行原理
客户端登录服务器，在服务器上存储了session，服务器会为该客户端创建一个session文件，
并把 session id 存储到客户端的cookie上

关于session的配置

session.save_handler = files            session保存在文件中
session.save_path = "c:/wamp/tmp"        保存文件的路径
session.use_cookies = 1                    是否使用cookie
session.use_only_cookies = 1            是否只使用cookie
session.name = PHPSESSID                cookie中sessionid的键名
session.auto_start = 0                    是否自动开启session
session.cookie_lifetime = 0                sessionid在 cookie的生存周期
session.cookie_path = /
session.cookie_domain =
session.cookie_httponly = 
session.serialize_handler = php            文件中存储session数据的方法
session.gc_probability = 1session.gc_divisor = 1000session.gc_maxlifetime = 1440            session默认保存时间 秒
session.use_trans_sid = 0

自定义session
① 设置 session的处理方式为用户自定义

session_module_name('user') 或  ini_set('')

② 设置回调函数控制session的处理流程

session_set_save_handler(open, close, read, werite, destroy, gc)open(sess_path, sess_name)close()read(sess_id)write(sess_id, sess_data)destroy(sess_id)gc(sess_lifetime)

session存储在自定义文件中
它的意义不大就不说了

session存储在数据库中
定义一个类来执行操作

<?php 
//session驱动 存储于 数据库
class DbSession{
	private static $pdo;

	//初始化
	public static function start(PDO $pdo){
		self::$pdo = $pdo;		//给属性赋值
		//设置session
		session_module_name('user');
		session_set_save_handler(
			array(__CLASS__, 'open'),
			array(__CLASS__, 'close'),
			array(__CLASS__, 'read'),
			array(__CLASS__, 'write'),
			array(__CLASS__, 'destroy'),
			array(__CLASS__, 'gc')
		);
		session_start();
	}

	//open
	public static function open($sess_path, $sess_name){
		return true;
	}

	//close
	public static function close(){
		return true;
	}

	//read
	public static function read($sess_id){
		$sql = "select sess_data from session where sess_id=?";
		$stmt = self::$pdo->prepare($sql);
		$stmt->execute(array($sess_id));
		$stmt->bindColumn('sess_data', $sess_data);
		$stmt->fetch();
		return $sess_data;
	}

	//write
	public static function write($sess_id, $sess_data) {
		//判断 之前是否 存储过session
		$sql = "select sess_data from session where sess_id=?";
		$stmt = self::$pdo->prepare($sql);
		$stmt->execute(array($sess_id));
		if ($stmt->rowCount() > 0) {
			//更新
			$sql = "update session set sess_data=?, sess_time=? where sess_id=?";
			$stmt = self::$pdo->prepare($sql);
			$stmt->execute(array($sess_data, time(), $sess_id));
		} else {
			//插入
			$sql = "insert into session(sess_id, sess_data, sess_time) values(?,?,?)";
			$stmt = self::$pdo->prepare($sql);
			$stmt->execute(array($sess_id, $sess_data, time()));
		}
	}

	//destroy
	public static function destroy($sess_id){
		$sql = "delete from session where sess_id=?";
		$stmt = self::$pdo->prepare($sql);
		$stmt->execute(array($sess_id));
		return true;
	}

	//gc
	public static function gc($sess_lifetime){
		$sql = "delete from session where sess_time<".(time()-$sess_lifetime);
		$stmt = self::$pdo->prepare($sql);
		$stmt->execute();
	}
	
}

try {
	$pdo = new PDO('mysql:host=localhost;dbname=s33', 'root', '123456');
	$pdo->exec('set names utf8');
} catch (PDOException $e) {
	echo $e->getMessage();exit;
}

//初始化
DbSession::start($pdo);
?>

数据库建表

create table session(
	sess_id char(32) not null primary key,
	sess_data text not null,
	sess_time int not null
)engine=innodb default charset=utf8;

测试

<?php 
header("Content-type:text/html;charset=utf-8");
require "./DbSession.class.php";


$_SESSION['username'] = "jiabrother";
$_SESSION['age'] = "45";
$_SESSION['grade'] = "s33";

//session_destroy();

echo "<hr>";

var_dump($_SESSION);
var_dump($_COOKIE);

?>
<a href="2.php">2.php</a>

session存储在 memcache

<?php 
header("Content-type:text/html;charset=utf-8");

ini_set('session.save_handler', 'memcache');
ini_set('session.save_path', '127.0.0.1:11211');

session_start();


$_SESSION['username'] = "jiabrother";
$_SESSION['age'] = "45";
$_SESSION['grade'] = "s33";

//session_destroy();

echo "<hr>";

var_dump($_SESSION);
var_dump($_COOKIE);

?>
<a href="2.php">2.php</a>

测试

<?php 
header("Content-type:text/html;charset=utf-8");
ini_set('session.save_handler', 'memcache');
ini_set('session.save_path', '127.0.0.1:11211');

session_start();

var_dump($_SESSION);
var_dump($_COOKIE);


$mem = new Memcache();
$mem->addServer('127.0.0.1', 11211);

echo $mem->get('okgmpf6dije13a88u4ikad6h31');
 ?>