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johanandren/CsvUnmarshalling.scala

Created September 7, 2016 16:04
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  1. johanandren created this gist Sep 7, 2016.
    31 changes: 31 additions & 0 deletions CsvUnmarshalling.scala
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    import akka.actor.ActorSystem
    import akka.http.scaladsl.unmarshalling.Unmarshal
    import akka.stream.ActorMaterializer

    import scala.concurrent.Await
    // important - it needs to be this Seq and not the default one
    import scala.collection.immutable.Seq

    // this is just for the await, so not really needed
    import scala.concurrent.duration._

    object CsvUnmarshalling extends App {

    // the String => Seq[T] csv unmarshaller is here
    import akka.http.scaladsl.unmarshalling.PredefinedFromStringUnmarshallers.CsvSeq
    // but it needs something that will make each seq entry from String => T
    // in our case T is String, so wee need a String => String unmarshaller
    // (that doesn't really do anything - also known as `identity` in fp-speak)
    // it can be found here:
    import akka.http.scaladsl.unmarshalling.Unmarshaller.identityUnmarshaller

    implicit val system = ActorSystem()

    // we need a materializer and an execution context in the implicit scope as well
    implicit val mat = ActorMaterializer()
    import scala.concurrent.ExecutionContext.Implicits.global

    val csv = "oh,such,csv,amaze,wow,wow\n"
    val seq = Unmarshal(csv).to[Seq[String]]
    println(Await.result(seq, 3.seconds))
    }