public function db_connect()
 {
     $mysqli = new \mysqli($this->config['db_host'], $this->config['db_user'], $this->config['db_pass'], $this->config['db_name']);
     //
     if ($mysqli->connect_errno) {
         Response::error(503, "503 Service Unavailable (DB connection failed): " . $mysqli->connect_error);
     }
     Utils::log("MySQL DB CONNECTED: " . json_encode($mysqli->get_charset()));
     return $mysqli;
 }
 private function getConnection()
 {
     try {
         return new MongoClient("mongodb://" . $this->config['user'] . ":" . $this->config['pass'] . "@127.0.0.1/" . $this->config['db']);
     } catch (MongoConnectionException $e) {
         Utils::log($e->getMessage());
         Response::error(500, 'DB connection failed (MongoDB).');
     }
 }
 /**
  * @return PDO
  */
 private function getConnection()
 {
     if (!is_null($this->connection)) {
         return $this->connection;
     }
     $connection = NULL;
     $host = $this->config['host'];
     $db = $this->config['db'];
     $user = $this->config['user'];
     $pass = $this->config['pass'];
     try {
         //$connection = new PDO("mssql:host=$host;dbname=$db;charset=UTF8", $user, $pass);
         $connection = new PDO("dblib:host={$host};dbname={$db};charset=UTF8", $user, $pass);
         //$connection = new PDO("sqlsrv:Server=$host;Database=$db", $user, $pass);
         //odbc:DRIVER=FreeTDS;SERVERNAME=mssql;DATABASE=
         $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
         Utils::log("DB CONNECTED");
         return $connection;
     } catch (PDOException $e) {
         Response::error(500, 'DB connection failed (SQL): ' . $e->getMessage());
     }
 }