保存SESSION到SQLITE,

1. [代码]保存SESSION到SQLITE    

<?php
/**
 * Sqlite保存SESSION
 * @author WeakSun <52132522@qq.com>
 */
namespace Think\Session\Driver;

use SessionHandlerInterface;
use PDO;

class Sqlite implements SessionHandlerInterface {

	static protected $tableNameName, $expire, $handler, $nowTime;

	public function __construct() {
		empty(static::$expire) && static::$expire = C('SESSION_EXPIRE', null, false) ? C('SESSION_EXPIRE') : ini_get('session.gc_maxlifetime');
		empty(static::$nowTime) && static::$nowTime = isset($GLOBALS['_beginTime']) ? $GLOBALS['_beginTime'] : microtime(true);
		empty(static::$tableNameName) && static::$tableNameName = C('SESSION_TABLE') ? C('SESSION_TABLE') : 'iSession';
		$dbFile = TEMP_PATH . 'Caches.tmp';
		$isCreate = is_file($dbFile);
		if (empty(static::$handler)) {
			static::$handler = new PDO("sqlite:{$dbFile}", null, null, array(PDO::ATTR_PERSISTENT => true));
			empty($isCreate) && $this->exec("PRAGMA encoding = 'UTF8';PRAGMA temp_store = 2;PRAGMA auto_vacuum = 0;PRAGMA count_changes = 1;PRAGMA cache_size = 9000;");
			$this->chkTable() || $this->createTable();
		}
	}

	/**
	 * 创建SessionID
	 * @return string
	 */
	public function create_sid() {
		return uniqid(sprintf('%08x', mt_rand(0, 2147483647)));
	}

	/**
	 * 打开session
	 * @param string $path
	 * @param string $name
	 * @return boolean
	 */
	public function open($path, $name) {
		return is_object(static::$handler);
	}

	/**
	 * 关闭Session
	 * @return boolean
	 */
	public function close() {
		return true;
	}

	/**
	 * 读取Session
	 * @param string $id
	 * @return string
	 */
	public function read($id = null) {
		$table = static::$tableNameName;
		$sth = static::$handler->query("SELECT `value` FROM `{$table}` WHERE `id`='{$id}' AND `expire` > strftime('%s','now') LIMIT 1", PDO::FETCH_NUM);
		if (!empty($sth)) {
			list($data) = $sth->fetch();
			unset($sth);
		} else {
			$data = '';
		}
		return $data;
	}

	/**
	 * 写入Session
	 * @param string $id
	 * @param string $data
	 * @return integer
	 */
	public function write($id = null, $data = null) {
		$table = static::$tableNameName;
		$expire = ceil(static::$expire + static::$nowTime);
		return $this->exec("REPLACE INTO `{$table}` VALUES('{$id}','{$data}',{$expire})");
	}

	/**
	 * 销毁Session
	 * @param string $id
	 * @return integer
	 */
	public function destroy($id = 0) {
		$table = static::$tableNameName;
		return $this->exec("DELETE FROM `{$table}` WHERE `id` = '{$id}'");
	}

	/**
	 * 垃圾回收
	 * @param string $expire
	 * @return integer
	 */
	public function gc($expire = 0) {
		$table = static::$tableNameName;
		return $this->exec("DELETE FROM `{$table}` WHERE `expire` < strftime('%s','now');VACUUM;");
	}

	/**
	 * 检查当前表是否存在
	 * @return bool 返回检查结果，存在返回True，失败返回False
	 */
	protected function chkTable() {
		return in_array(static::$tableNameName, $this->getTables());
	}

	/**
	 * 获取当前数据库的数据表列表
	 * @return array 返回获取到的数据表列表数组
	 */
	protected function getTables() {
		$tables = $data = array();
		$sth = $this->query("SELECT `name` FROM `sqlite_master` WHERE `type` = 'table' UNION ALL SELECT `name` FROM `sqlite_temp_master`");
		if (!empty($sth)) {
			while ($row = $sth->fetch(PDO::FETCH_NUM, PDO::FETCH_ORI_NEXT)) {
				$tables[] = $row[0];
			}
			unset($sth, $row);
		}
		return $tables;
	}

	/**
	 * 创建当前数据表
	 * @return integer 成功返回1，失败返回0
	 */
	protected function createTable() {
		$tableName = static::$tableNameName;
		return $this->exec("CREATE TABLE IF NOT EXISTS `{$tableName}` (`id` VARCHAR PRIMARY KEY ON CONFLICT FAIL NOT NULL COLLATE 'NOCASE',`value` TEXT NOT NULL,`expire` INTEGER NOT NULL);");
	}

	public function __call($method, $arguments) {
		if (method_exists(self::$handler, $method)) {
			return call_user_func_array(array(self::$handler, $method), $arguments);
		} else {
			E(__CLASS__ . ':' . $method . L('_METHOD_NOT_EXIST_'));
			return;
		}
	}

}