/**
* Lookup nonce value for the tool consumer.
*
* @param OAuthConsumer $consumer OAuthConsumer object
* @param string $token Token value
* @param string $value Nonce value
* @param string $timestamp Date/time of request
* @return boolean True if the nonce value already exists
*/
function lookup_nonce($consumer, $token, $value, $timestamp)
{
$nonce = new LTI_Consumer_Nonce($this->tool_provider->consumer, $value);
$ok = !$nonce->load();
if ($ok) {
$ok = $nonce->save();
}
if (!$ok) {
$this->tool_provider->reason = 'Invalid nonce.';
}
return !$ok;
}
