1. class Db
    2. {
    3.     private static $instance;
    5.     private function __construct(){}
    6.     private function __clone(){}
    8.     public static function instance(){
    9.         $database = require_once dirname(__DIR__).'/database.php';
    10.         if (!self::$instance){
    11.             $dsn = 'mysql:dbname='.$database['database'].';host='.$database['hostname'].':'.$database['hostport'];
    12.             $user = $database['username'];
    13.             $password = $database['password'];
    15.             try {
    16.                 self::$instance = new \PDO($dsn, $user, $password);
    17.                 } catch (PDOException $e) {
    18.                 echo 'Connection failed: ' . $e->getMessage();
    19.             }
    20.         }
    21.         return self::$instance;
    22.     }
    23. }