optionMarshaller - is None returning a 200 what we really want?

[ktoso]

Hi @sirthias @jrudolph,
I was reading this blogpost : http://danielasfregola.com/2016/02/07/how-to-build-a-rest-api-with-akka-http/

And realised that when we have an Option[String] for example, and we complete with a None the default EmptyValue[] mechanism kicks in and the response will be a 200 response. Is there some deeper reason behind that? I would have thought a 404 would be more appropriate to model the None case.

Code in question:

  implicit def optionMarshaller[A, B](implicit m: Marshaller[A, B], empty: EmptyValue[B]): Marshaller[Option[A], B] =
    Marshaller { implicit ec ⇒
      {
        case Some(value) ⇒ m(value)
        case None        ⇒ FastFuture.successful(Marshalling.Opaque(() ⇒ empty.emptyValue) :: Nil)
      }
    }

Let me know if there's a story behind the 200 response there or if we simply should fix it, thanks a lot in advance!

// Yup I'm back from vacation, was great (now a bit sick though), so back to hacking full speed now :-)

[sirthias]

I don't think there is generally "correct" semantic for marshalling None.
Depending on the application None could rendered to a 200 Ok, 204 No Content, 404 Not Found or any other kind of response.

Note that in the case you want a 404 response you can use the rejectEmptyResponse directive which was inherited from spray (http://spray.io/documentation/1.2.2/spray-routing/misc-directives/rejectEmptyResponse/) and is part of the MiscDirectives.

[ktoso]

That's true as well that the right answer is "it depends" here hm...
Instead of changing behaviour I'll document how to change the none case by providing an EmptyValue implicitly and mention rejectEmptyResponse then.

[ktoso]

Closing for now as obsolete