I have copied Spray Client's example code into my own project, to have it easily available. I use IntelliJ 13.
Here is the code I have:
package mypackage
import scala.util.Success
import scala.concurrent.duration._
import akka.actor.ActorSystem
import akka.pattern.ask
import akka.event.Logging
import akka.io.IO
import spray.json.{JsonFormat, DefaultJsonProtocol}
import spray.can.Http
import spray.util._
import spray.client.pipelining._
import scala.util.Success
import scala.util.Failure
case class Elevation(location: Location, elevation: Double)
case class Location(lat: Double, lng: Double)
case class GoogleApiResult[T](status: String, results: List[T])
object ElevationJsonProtocol extends DefaultJsonProtocol {
implicit val locationFormat = jsonFormat2(Location)
implicit val elevationFormat = jsonFormat2(Elevation)
implicit def googleApiResultFormat[T :JsonFormat] = jsonFormat2(GoogleApiResult.apply[T])
}
object SprayExample extends App {
// we need an ActorSystem to host our application in
implicit val system = ActorSystem("simple-spray-client")
import system.dispatcher // execution context for futures below
val log = Logging(system, getClass)
log.info("Requesting the elevation of Mt. Everest from Googles Elevation API...")
val pipeline = sendReceive ~> unmarshal[GoogleApiResult[Elevation]]
val responseFuture = pipeline {
Get("http://maps.googleapis.com/maps/api/elevation/json?locations=27.988056,86.925278&sensor=false")
}
responseFuture onComplete {
case Success(GoogleApiResult(_, Elevation(_, elevation) :: _)) =>
log.info("The elevation of Mt. Everest is: {} m", elevation)
shutdown()
case Success(somethingUnexpected) =>
log.warning("The Google API call was successful but returned something unexpected: '{}'.", somethingUnexpected)
shutdown()
case Failure(error) =>
log.error(error, "Couldn't get elevation")
shutdown()
}
def shutdown(): Unit = {
IO(Http).ask(Http.CloseAll)(1.second).await
system.shutdown()
}
}
As it stands, this works perfectly and it prints the height of Mt.Everest as expected.
The strange thing happens if I move the file down one level in the package structure, that is I create a mypackage.myinnerpackage
and move the file inside it.
IDEA changes my first line of code into package mypackage.myinnerpackage
and that's it.
Then I try to run the app and the compilation will fail with the following message:
could not find implicit value for evidence parameter of type spray.httpx.unmarshalling.FromResponseUnmarshaller[courserahelper.sprayexamples.GoogleApiResult[courserahelper.sprayexamples.Elevation]]
val pipeline = sendReceive ~> unmarshal[GoogleApiResult[Elevation]]
^
I did not change anything in the code, I effectively just changed the package! Additionally, this code is self contained, it does not rely on any other implicit I declared in any other part of my code....
What am I missing?
Thanks!