Generic REST API with Akka HTTP? - scala

Question

Let's say you have 100 models, and for all of them you want the client to be able to do GET/POST/PUT/DELETE.
I read this article and a few others, but even with the promising title it seems that a lot of code would have to be duplicated for each model. Boilerplate, as some would call it.
Ideally I want to be able to say something like
case class AwesomeCaseClass(primeNumber : Long)
case class EvenMoreAwesomeCaseClass(favoritePrimeNumber : Long)
and then specify either all commands that should be accepted for each class (or maybe things like UPSERT).
I cannot find anyone who has done this, can anyone provide a link or a pointer in the right direction?
When Googling I also came across this, but for Akka HTTP in particular there seemed to only be support for API documentation.
Here is my attempt so far:
package route
import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.HttpResponse
import akka.http.scaladsl.server.Route
import akka.stream.ActorMaterializer
import scala.reflect._
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller
/**
* Created by flyrev on 30.05.16.
*/
case class Test(name: String)
class REST[T](implicit um: FromRequestUnmarshaller[T]) {
def generateRoute(klazz: Class[_]) : Route = {
path("test" / klazz.getSimpleName) {
get {
complete(HttpResponse(entity = "OK", status = 200))
} ~ post {
entity(as[T]) {
// Insert into DB here
(zomg) => complete(HttpResponse(entity = "Would have POSTed that stuff", status = 200))
}
}
} ~ get {
complete(HttpResponse(entity="Not found", status=404))
}
}
}
object GenerateRouteFromClass extends App {
def runtimeClass[T: ClassTag] = classTag[T].runtimeClass
implicit val system = ActorSystem()
implicit val materializer = ActorMaterializer()
import argonaut._
import CodecJson.derive
implicit val um = derive[Test]
Http().bindAndHandle(new REST[Test].generateRoute(runtimeClass[Test]), "localhost", 8080)
}
However, this gives:
Error:(45, 24) could not find implicit value for parameter um: akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller[route.Test]
Http().bindAndHandle(new REST[Test].generateRoute(runtimeClass[Test]), "localhost", 8080)
^
Error:(45, 24) not enough arguments for constructor REST: (implicit um: akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller[route.Test])route.REST[route.Test].
Unspecified value parameter um.
Http().bindAndHandle(new REST[Test].generateRoute(runtimeClass[Test]), "localhost", 8080)
^