如何将Source [String，Future [IOResult]]转换为Source [ByteString，Future [IOResult]]] >> [

Question

需要转换

val graph: Source[String, Future[IOResult]]= <some flow>

到

val graph: Source[ByteString, Future[IOResult]] =<some flow>

以便可以将其传递给Result，如下所示：

Result(
        header = ResponseHeader(OK, Map(CONTENT_DISPOSITION → s"application")),
        body = HttpEntity.Streamed(graph, None, None)
        )

任何帮助将不胜感激。谢谢。

需要转换值图：Source [String，Future [IOResult]] == [[到值图：Source [ByteString，Future [IOResult]] =

以便可以将其传递给Result，如图所示。] >

Answer 1

val byteStringSource: Source[ByteString, Future[IOResult]] =
  graph.via(Flow.fromFunction(ByteString(_)))