function getCancelURL()
{
if (!$this->return_to) {
return new Auth_OpenID_NoReturnToError();
}
if ($this->immediate) {
return new Auth_OpenID_ServerError(null,
"Cancel is not an appropriate \
response to immediate mode \
requests.");
}
$response = new Auth_OpenID_Message(
$this->message->getOpenIDNamespace());
$response->setArg(Auth_OpenID_OPENID_NS, 'mode', 'cancel');
return $response->toURL($this->return_to);
}