Di seguito è riportato un semplice attore che è necessario effettuare una chiamata HTTP per ricevere dati da un'API. Secondo lo Akka HTTP Core Request-Level Client-Side API sono necessari solo gli ActorSystem
e ActorMaterializer
.È possibile effettuare una richiesta del client core Akka HTTP all'interno di un attore?
class MyActor extends Actor {
import context.system
implicit val materializer = ActorMaterializer()
override def receive: Receive = {
case _ => {
val responseFuture: Future[HttpResponse] = Http().singleRequest(HttpRequest(uri = "http://akka.io"))
responseFuture onComplete {
case Success(res) => println(res)
case Failure(t) => println("An error has occured: " + t.getMessage)
}
}
}
}
Tuttavia, quando si tenta di compilare l'applicazione ricevo i seguenti messaggi di errore:
Error:(18, 48) ambiguous implicit values: both value context in trait Actor of type => akka.actor.ActorContext and method system in trait ActorContext of type => akka.actor.ActorSystem match expected type akka.actor.ActorRefFactory
implicit val materializer = ActorMaterializer()
Error:(18, 48) implicit ActorRefFactory required: if outside of an Actor you need an implicit ActorSystem, inside of an actor this should be the implicit ActorContext
implicit val materializer = ActorMaterializer()
Error:(18, 48) not enough arguments for method apply: (implicit context: akka.actor.ActorRefFactory)akka.stream.ActorMaterializer in object ActorMaterializer. Unspecified value parameter context.
implicit val materializer = ActorMaterializer()
Error:(22, 70) could not find implicit value for parameter fm: akka.stream.Materializer
val responseFuture: Future[HttpResponse] = Http().singleRequest(HttpRequest(uri = "http://akka.io"))
Error:(22, 70) not enough arguments for method singleRequest: (implicit fm: akka.stream.Materializer)scala.concurrent.Future[akka.http.scaladsl.model.HttpResponse]. Unspecified value parameter fm.
val responseFuture: Future[HttpResponse] = Http().singleRequest(HttpRequest(uri = "http://akka.io"))
Error:(23, 22) Cannot find an implicit ExecutionContext. You might pass an (implicit ec: ExecutionContext) parameter to your method or import scala.concurrent.ExecutionContext.Implicits.global.
responseFuture onComplete {
Error:(23, 22) not enough arguments for method onComplete: (implicit executor: scala.concurrent.ExecutionContext)Unit. Unspecified value parameter executor.
responseFuture onComplete {
E 'questo il modo corretto di effettuare una chiamata HTTP all'interno di un Akka attore?
Modifica
Incluso import ExecutionContext.Implicits.global
per sistemare le ultime due ExecutionContext
errori.