private function get_version(&$request)
{
$version = $request->get_parameter("oauth_version");
if (!$version) {
// Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present.
// Chapter 7.0 ("Accessing Protected Ressources")
$version = '1.0';
}
if ($version !== $this->version) {
throw new OAuthException("OAuth version '{$version}' not supported");
}
return $version;
}