如何让 akka-http 将 GET 请求转发到 POST 请求并更改属性？

问题描述

我正在使用 akka-http 处理 get 请求，我想转发到同一台主机，但更改以下参数：

• 将 GET 转换为 POST
• 将端口从 8080 更改为 8081
• 擦除参数并发送 JSON。我已经创建了要发送的 JSON 值。

我咨询了这个 page 和这个 answer。我正在使用 extract(_.request) { request => 提取请求，然后使用 redirect( 创建一个 StatusCodes.MovedPermanently。

val routes: Route = {
    get {
      (path(IntNumber) & parameterSeq) { (adId: Int,params: Seq[(String,String)]) =>
        // handling requests as: "http://localhost:8080/2?c=5&b=2",make sure to use the request between quotes
        println(s"The ad ID: $adId contains the parameters: ${params.map(paramString).mkString(",")}")

        val bid = getBid(adId,params)
        println(s"bid request: ${bid.toJson.prettyPrint}")

        // HOW TO REDIRECT TO ANOTHER PORT,CHANGE THE METHOD FROM GET TO POST,AND SEND A JSON PAYLOAD?
        val newRequest = HttpRequest(
          HttpMethods.POST,uri = "/",entity = httpentity(ContentTypes.`application/json`,bid.toJson.toString)
        )

        redirect(
          newRequest
            .uri
            .withHost("localhost")
            .withPort(8082),StatusCodes.MovedPermanently
        )
        // complete(StatusCodes.OK)

      } ~ pathEndOrSingleSlash {
        complete(StatusCodes.BadRequest)
      } ~ {
        complete(StatusCodes.Forbidden)
      }
    }
  }

但是当我向 akka-http 应用程序 $ http GET "localhost:8080/3?b=5&c=10&d=19&c=10" 发送 get 时，端口 8082 上的服务器没有应答。

$ http GET "localhost:8080/3?b=5&c=10&d=19&c=10"
HTTP/1.1 301 Moved Permanently
Content-Length: 92
Content-Type: text/html; charset=UTF-8
Date: Fri,19 Feb 2021 15:49:21 GMT
Location: //localhost:8082/
Server: akka-http/10.2.2

This and all future requests should be directed to <a href="//localhost:8082/">this URI</a>.

要测试服务器是否正常工作，我可以发送 POST 请求并收到答复：

$ http POST localhost:8082 < src/main/resources/bidders-request-10.json 
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
Date: Fri,19 Feb 2021 15:51:02 GMT
Server: Apache-Coyote/1.1
transfer-encoding: chunked

{
    "bid": 0,"content": "b:$price$","id": "10"
}

解决方法

因此，我通过创建一个执行 Http().singleRequest(HttpRequest(uri = "https://akka.io")) 之类的角色来解决 this example。我的工作解决方案是：

import akka.actor.{Actor,ActorLogging,ActorSystem,Props}
import akka.http.scaladsl.Http
import akka.http.scaladsl.model._
import akka.util.ByteString
import spray.json._
import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport

object MyselfClient {
  def main(args: Array[String]): Unit = {
    val system = ActorSystem("AuctionClientSystem")
    val auctionClientActor = system.actorOf(Props[AuctionClientActor],"auctionClientActor")
    auctionClientActor ! BidRequest(1,Bid(2,List(("c","5"),("b","2"))))
  }
}

case class BidRequest(requestId: Int,bid: Bid)

class AuctionClientActor extends Actor with ActorLogging
      with BidJsonProtocol with SprayJsonSupport {

  import akka.pattern.pipe
  import context.dispatcher

  implicit val system = context.system
  val http = Http(system)

  def receive = {
    case bidRequest@BidRequest(requestId,bid) =>
      println(s"received bid request: $bidRequest")
      val content = bidRequest.bid.toJson.toString
        .replace("[[","{")
        .replace("]]","}")
        .replace("\",\"","\": \"")
        .replace("[","")
        .replace("]","")
      println(content)
      // create the request
      val httpRequest = HttpRequest(
        HttpMethods.POST,uri = Uri("http://localhost:8081"),entity = HttpEntity(
          ContentTypes.`application/json`,content
          // """{"id": 10,"attributes" : { "a": "1","b": "0" }}""".stripMargin
        )
      )
      // send the request
      http.singleRequest(httpRequest).pipeTo(self)
    case HttpResponse(StatusCodes.OK,headers,entity,_) =>
      entity.dataBytes.runFold(ByteString(""))(_ ++ _).foreach { body =>
        println("Got response,body: " + body.utf8String)
      }
    case resp@HttpResponse(code,_,_) =>
      println("Request failed,response code: " + code)
      resp.discardEntityBytes()
  }
}

我就是不知道如何让 Spray JSON 不使用 [ 和 ]。然后我正在使用 .replace("[[","{") 进行令人讨厌的对话。但是，该解决方案已经在起作用。我正在寻找一种更好的方法来转换它。我想还有另一种形式可以创建没有 [ 和 ] 的案例类。

import spray.json._

case class Bid(id: Int,attributes: List[(String,String)])

trait BidJsonProtocol extends DefaultJsonProtocol {
  implicit val bidFormat = jsonFormat2(Bid)
}