/**
* Grabs the 1st stage code from the request object
*
* @return string/null
* @throws Exception\OAuth2Exception
*/
public function getCodeFromRequest()
{
$query = $this->request->query();
if ($query->offsetExists($this->options->stage1Response->error->accessKey)) {
throw new OAuth2Exception('Error gaining authorisation: ' . $query->get($this->options->stage1Response->error->accessKey));
}
if ($query->offsetExists($this->options->stage1Response->code->accessKey)) {
if ($query->get($this->options->stage1Response->state->accessKey) !== $this->session->state) {
throw new OAuth2Exception('Error gaining authorisation: state mismatch');
}
return $query->get($this->options->stage1Response->code->accessKey);
}
return null;
}