播放文件上传：警告：在收到请求结束前发送2xx'早期'响应

Question

尝试“播放Scala文件上传示例”，我收到以下警告：

[warn] a.a.ActorSystemImpl - Sending an 2xx 'early' response before end of request was received... Note that the connection will be closed after this response. Also, many clients will not read early responses! Consider only issuing this response after the request data has been completely read!

有没有办法避免这种警告？

完整的源代码可以在这里找到：https://github.com/playframework/play-scala-fileupload-example/tree/2.6.x

这是文件上传处理请求的详细信息：

  type FilePartHandler[A] = FileInfo => Accumulator[ByteString, FilePart[A]]

  /**
   * Uses a custom FilePartHandler to return a type of "File" rather than
   * using Play's TemporaryFile class.  Deletion must happen explicitly on
   * completion, rather than TemporaryFile (which uses finalization to
   * delete temporary files).
   *
   * @return
   */
  private def handleFilePartAsFile: FilePartHandler[File] = {
    case FileInfo(partName, filename, contentType) =>
      val path: Path = Files.createTempFile("multipartBody", "tempFile")
      val fileSink: Sink[ByteString, Future[IOResult]] = FileIO.toPath(path)
      val accumulator: Accumulator[ByteString, IOResult] = Accumulator(fileSink)
      accumulator.map {
        case IOResult(count, status) =>
          logger.info(s"count = $count, status = $status")
          FilePart(partName, filename, contentType, path.toFile)
      }
  }

  /**
   * A generic operation on the temporary file that deletes the temp file after completion.
   */
  private def operateOnTempFile(file: File) = {
    val size = Files.size(file.toPath)
    logger.info(s"size = ${size}")
    Files.deleteIfExists(file.toPath)
    size
  }

  /**
   * Uploads a multipart file as a POST request.
   *
   * @return
   */
  def upload = Action(parse.multipartFormData(handleFilePartAsFile)) { implicit request =>
    val fileOption = request.body.file("name").map {
      case FilePart(key, filename, contentType, file) =>
        logger.info(s"key = ${key}, filename = ${filename}, contentType = ${contentType}, file = $file")
        val data = operateOnTempFile(file)
        data
    }

    Ok(s"file size = ${fileOption.getOrElse("no file")}")
  }

Answer 1

这是Play中的一个错误，我刚刚修复了here。它只发生在分块请求时才会发生。它可以通过使用Play的Netty服务器后端而不是Akka HTTP来解决。