extract method

Implementation

@override
Future<Result<String, Rejection>> extract(Request request) async {
  final header = Authorization.of(request);
  if (header == null || !header.isScheme('bearer')) {
    return Err(
      Rejection.unauthorized(
        'expected a bearer token',
        challenge: challenge,
      ),
    );
  }
  if (header.credentials.isEmpty) {
    return Err(
      Rejection.unauthorized('the bearer token is empty',
          challenge: challenge),
    );
  }
  return Ok(header.credentials);
}