FollowRedirectWorkaround.scala

import akka.actor.ActorRef
import akka.util.Timeout
import concurrent.{Promise, Future, ExecutionContext}
import spray.http.{HttpMethods, HttpResponse, HttpRequest}
import spray.client.pipelining._
import spray.http.StatusCodes.Redirection
import concurrent.Promise._
import spray.http.HttpMethods._
import scala.concurrent.duration._

/**
 * Work around for this: https://github.com/spray/spray/issues/132
 * 
 * Use sendReceiveFollowRedirect in place of spray.client.pipelining#sendReceive in your pipelines. Like so:
 * val pipeline = (
 *   addHeader("blah", "blah")
 *     ~> sendReceiveFollowRedirect(httpClient)
 *     ~> unmarshal[AccountResponse]
 * )
 */
object FollowRedirectWorkaround {

  val MAX_REDIRECTS = 5

  def sendReceiveFollowRedirect(transport: ActorRef, futureTimeout: Timeout = 30 seconds span)
                               (implicit ec: ExecutionContext): HttpRequest => Future[HttpResponse] = {
    sendReceiveFollowRedirectInternal(transport, 0, futureTimeout)
  }

  private def sendReceiveFollowRedirectInternal(transport: ActorRef, depth:Int, futureTimeout: Timeout = 30 seconds span)
                                               (implicit ec: ExecutionContext): HttpRequest => Future[HttpResponse] = {
    request => {
      sendReceive(transport, futureTimeout).apply(request).flatMap(x => {
        val location = x.headers.find(_.lowercaseName == "location")
        if(x.status.isInstanceOf[Redirection] && location.isDefined && depth < MAX_REDIRECTS) {
          val newReq = request.copy(uri = location.get.value, method = GET)
          sendReceiveFollowRedirectInternal(transport, depth+1, futureTimeout).apply(newReq)
        } else {
          successful(x).future
        }
      })
    }
  }
}