<?php
/*
CREATE TABLE IF NOT EXISTS `session` (
`session_id` varchar(32) NOT NULL,
`data` text NOT NULL,
`expire` datetime NOT NULL,
PRIMARY KEY (`session_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
*/
namespace Session;
/**
* 数据库缓存类
* @package Session
*/
final class DB {
// 过期时间
public $expire = '';
// 构造方法
public function __construct($registry) {
// 注册实例
$this->db = $registry->get('db');
// 设置最大生命周期
$this->expire = ini_get('session.gc_maxlifetime');
}
// 读取缓存
public function read($session_id) {
$query = $this->db->query("SELECT `data` FROM `" . DB_PREFIX . "session` WHERE session_id = '" . $this->db->escape($session_id) . "' AND expire > '" . $this->db->escape(date('Y-m-d H:i:s', time())) . "'");
if ($query->num_rows) {
return json_decode($query->row['data'], true);
} else {
return false;
}
}
// 写入缓存
public function write($session_id, $data) {
if ($session_id) {
$this->db->query("REPLACE INTO `" . DB_PREFIX . "session` SET session_id = '" . $this->db->escape($session_id) . "', `data` = '" . $this->db->escape(json_encode($data)) . "', expire = '" . $this->db->escape(date('Y-m-d H:i:s', time() + $this->expire)) . "'");
}
return true;
}
// 销毁指定id缓存
public function destroy($session_id) {
$this->db->query("DELETE FROM `" . DB_PREFIX . "session` WHERE session_id = '" . $this->db->escape($session_id) . "'");
return true;
}
// 销毁过期缓存
public function gc($expire) {
$this->db->query("DELETE FROM `" . DB_PREFIX . "session` WHERE expire < '" . $this->db->escape(date('Y-m-d H:i:s', time())) . "'");
return true;
}
}