Spray client Pipeline error

[Eric Weise]

I am getting a couple of errors trying to build a simple pipeline that adds a header and does a post

[error] /Users/eweise/workspace/block-reporter-cell/src/main/scala/com/messagebus/block/app/Poster.scala:91: could not find implicit value for parameter aux: spray.httpx.TransformerAux[spray.http.HttpRequest,scala.concurrent.Future[spray.http.HttpResponse],spray.http.HttpRequest,spray.http.HttpRequest,R]

[error]     sendReceive ~> addHeader("X-My-Special-Header", "fancy-value")

[error]                 ^

[error] /Users/eweise/workspace/block-reporter-cell/src/main/scala/com/messagebus/block/app/Poster.scala:97: could not find implicit value for evidence parameter of type spray.httpx.marshalling.Marshaller[com.messagebus.block.model.Block]

[error]     Await.result(pipeline(Post("blocks", item)), 10000 millis)

[

My code looks like;

object BlockJsonProtocol extends DefaultJsonProtocol {

  implicit val orderFormat = jsonFormat3(Block)

}

class Poster extends Logging {

  import spray.http._

  import scala.concurrent.duration._

  import akka.actor.ActorSystem

  import spray.client.pipelining._

  import scala.concurrent.duration._

  import TransformerAux._

  import spray.client.pipelining._

  implicit val system = ActorSystem()

  implicit val timeout = Timeout(20 seconds)

  import system.dispatcher

  val pipeline: HttpRequest => Future[HttpResponse] = (sendReceive ~> addHeader("X-My-Special-Header", "fancy-value"))

  def handle(item: Block) = {

    import BlockJsonProtocol._

    Await.result(pipeline(Post("blocks", item)), 10000 millis)

  }

}

Can anyone tell me what I'm doing wrong or point me to an example that adds a header and does a post? I'm finding this DSL extremely difficult to use so if anyone can show me a more straightforward way to do a simple post without all the magic I would greatly appreciate it.

Eric

[Mathias Doenitz]

Eric,

the basic structure of a spray-client pipeline is this:

{request-transformation-stuff} ~> sendReceive ~> {response-transformation-stuff}

In your example:

sendReceive ~> addHeader("X-My-Special-Header", "fancy-value")

you use request transformation stuff (`addHeader`) on the response side of things, which cannot work.

If you want to add a header to the request you need to put the `addHeader` bit *before* the `sendReceive`.

Cheers,
Mathias

---
mat...@spray.io
http://spray.io

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[Eric Weise]

Thanks for the response Mathius. Your explanation makes things much clearer.

Eric