Question

我正在尝试构建一个自定义的Akka HTTP指令，该指令将响应异步映射到另一个响应。给出以下定义：

trait ResponseFilter {
  def apply(request: HttpRequest, response: HttpResponse): Future[HttpResponse]
}

我想建立与此类似的指令（不会编译）：

def filterResponse(responseFilter: ResponseFilter): Directive0 = {
  extractRequest { request =>
    mapResponse { response =>
      responseFilter(request, response)
    }
  }
}

编译器错误为：

...type mismatch;
[error]  found   : scala.concurrent.Future[akka.http.scaladsl.model.HttpResponse]
[error]  required: akka.http.scaladsl.model.HttpResponse
[error]         responseFilter(request, response)
[error]               ^
[error] one error found

这很有意义，因为mapResponse是同步的。

我知道onSuccess，但似乎无济于事。

Answer 1

我在Akka HTTP来源上花了一些时间，并提出了以下解决方案，该解决方案似乎可以正常工作：

  def filterResponse(responseFilter: ResponseFilter): Directive0 = {
    Directive { inner => ctx =>
      implicit val ec = ctx.executionContext

      inner(())(ctx).flatMap {
        case result: Complete =>
          responseFilter(ctx.request, result.response).map { filteredResponse =>
            RouteResult.Complete(filteredResponse)
          }
        case incomplete => Future.successful(incomplete)
      }
    }
  }

如果有更好的方法，请告诉我！

自定义Akka HTTP指令以异步映射响应

1 个答案: