public function checkUser()
{
    $valid_passwords = ["admin" => "123"];
    $valid_users = array_keys($valid_passwords);

    $user = $_SERVER['PHP_AUTH_USER'];
    $pass = $_SERVER['PHP_AUTH_PW'];

    $validated = (in_array($user, $valid_users)) && ($pass == $valid_passwords[$user]);

    if (!$validated) {
        header('WWW-Authenticate: Basic realm="My Realm"');
        header('HTTP/1.0 401 Unauthorized');
        die ("Not authorized");
    }

// If arrives here, is a valid user.
    return true;
    }

}