uploadRoute.scala

(path("upload") & extractLog) { log =>
        post {
          entity(as[Multipart.FormData]) { formdata =>
            val partsSource = formdata.parts
            val partsFlow   = Flow[Multipart.FormData.BodyPart].map { fileData => {
              if (fileData.name == "myFile") {
                val filename = "./data/" + fileData.filename.getOrElse("tempFile_" + System.currentTimeMillis())
                val file = new File(filename)
                val fileContentsSource = fileData.entity.dataBytes
                Left(fileContentsSource, file)
              } else {
                Right(new RuntimeException("Not Expected File"))
              }
             }
            }
            val fileSink = Sink.fold[Future[IOResult], Either[(Source[ByteString, Any], File), RuntimeException]](Future(new IOResult(1L, Success(Done)))) {
              case (_, Left((src, file))) =>
                src.runWith(FileIO.toPath(file.toPath))

              case (_, Right(ex)) =>
                Future(new IOResult(1L, Failure(ex)))

            }

            onComplete(partsSource.via(partsFlow).runWith(fileSink).flatten) {
              case Success(value) =>
                value match {
                  case res@IOResult(_, _) =>
                    if (res.wasSuccessful) complete("Successful Upload")
                    else {
                      log.error(s"Exception ${res.getError}")
                      complete("Unsuccessful Upload")
                    }
                }
              case Failure(ex) =>
                log.error(s"Exception Received $ex")
                complete("Unsuccessful Upload")
            }
          }
        }
    }