protected function addToken()
{
do {
$token = $this->generateToken();
$sql = $this->pdo->prepare('INSERT INTO `upload_token` (`token`) VALUES ( :token )');
$sql->execute(array(':token' => $token));
} while (!$this->pdo->lastInsertId());
$token = new UploadToken($this->pdo->lastInsertId(), $token);
$this->tokens[$token->getToken()] = array('id' => $token->getId());
return $token;
}
