保存SESSION到SQLITE

 
<?php
/**
 * Sqlite保存SESSION
 */
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;
        }
    }
  
}