Spray Client example

gistfile1.scala

// Akka Actor system
import akka.actor.ActorSystem

// HTTP related imports
import spray.http.{ HttpRequest, HttpResponse }
import spray.client.pipelining.{ Get, sendReceive }

// Futures related imports
import scala.concurrent.Future
import scala.util.{ Success, Failure }

// http://stackoverflow.com/questions/20593280/error-with-akka
// add dependency typesafe-config.jar

// Need to wrap in a package to get application supervisor actor
// "you need to provide exactly one argument: the class of the application supervisor actor"
package main.scala {

  // trait with single function to make a GET request
  trait WebClient {
    def get(url: String): Future[String]
  }

  // implementation of WebClient trait
  class SprayWebClient(implicit system: ActorSystem) extends WebClient {
    import system.dispatcher

    // create a function from HttpRequest to a Future of HttpResponse
    val pipeline: HttpRequest => Future[HttpResponse] = sendReceive

    // create a function to send a GET request and receive a string response
    def get(url: String): Future[String] = {
      val futureResponse = pipeline(Get(url))
      futureResponse.map(_.entity.asString)
    }
  }

  object Program extends Application {
    import system.dispatcher // execution context for futures

    // bring the actor system in scope
    implicit val system = ActorSystem()

    // create the client
    val webClient = new SprayWebClient()(system)

    // send GET request with absolute URI
    val futureResponse = webClient.get("https://ripple-rest.herokuapp.com/api/v1/status")

    // wait for Future to complete
    futureResponse onComplete {
      case Success(response) => println(response)
      case Failure(error) => println("An error has occured: " + error.getMessage)
    }
  }
}