Scala compiler can't find the unmarshalling implicits in route declaration - scala

Question

I'm trying to build a REST server using this tutorial:
https://spindance.com/reactive-rest-services-akka-http/
However, having reached the "Responding with JSON" section, I've noticed that my code doesn't compile, and I can't make POST requests. This is the error that I'm getting:
Error:(59, 18) could not find implicit value for parameter um: akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller[Health]
entity(as[Health]) { statusReport =>
^
Having looked at other tutorials, I've found out that you need to include an object containing an implicit variable for the class that I'm trying to unmarshall. I did that, and I even imported the httpx library, but I'm still getting this error. My code is given below.
import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.StatusCodes
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.server.Route
import akka.stream.ActorMaterializer
import akka.pattern.ask
import akka.util.Timeout
import spray.json._
import DefaultJsonProtocol._
import spray.httpx.SprayJsonSupport.sprayJsonUnmarshaller
import scala.concurrent.duration._
import scala.io.StdIn
object JsonImplicits extends DefaultJsonProtocol {
implicit val healthFormat = jsonFormat2(Health)
}
object MyApplication {
val host = "localhost"
val port = 8080
def main(args: Array[String]): Unit = {
implicit val system = ActorSystem("simple-rest-system")
// Something to do with flows
implicit val materializer = ActorMaterializer()
// A reference to a specific thread pool
// You can configure thread pool options through it
// It is the engine that executes the actors
implicit val executionContext = system.dispatcher
val requestHandler = system.actorOf(RequestHandler.props(), "requestHandler")
//Define the route
val route : Route = {
implicit val timeout = Timeout(20 seconds)
import JsonImplicits._
import spray.httpx.SprayJsonSupport._
path("health") {
get {
onSuccess(requestHandler ? GetHealthRequest) {
case response: HealthResponse =>
complete(StatusCodes.OK, s"Everything is ${response.health.status}!")
case _ =>
complete(StatusCodes.InternalServerError)
}
}
} ~ post {
// Entity extracts the body of the POST request and then converts it into a
// Health object
entity(as[Health]) { statusReport =>
onSuccess(requestHandler ? SetStatusRequest(statusReport)) {
case response: HealthResponse =>
complete(StatusCodes.OK,s"Posted health as ${response.health.status}!")
case _ =>
complete(StatusCodes.InternalServerError)
}
}
}
}
//Start up and listen for requests
val bindingFuture = Http().bindAndHandle(route, host, port)
println(s"Waiting for requests at http://$host:$port/...\nHit RETURN to terminate")
StdIn.readLine()
//Shutdown
bindingFuture.flatMap(_.unbind())
system.terminate()
}
}