如何从Akka HTTP POST请求读取JSON正文并以JSON数组形式发送最终响应

问题描述 投票：1回答：4

我是akka http的新手。我创建了一个程序来使用http进行发布请求，如下所示-

object MainController {


  def main(args: Array[String]) {
    implicit val system = ActorSystem()
    implicit val materializer = ActorMaterializer()
    implicit val executionContext = system.dispatcher

    val serverSource = Http().bind(interface = "localhost", port = 9000)

    val requestHandler: HttpRequest => HttpResponse = {
      case HttpRequest(GET, Uri.Path("/welcome"), _, _, _) =>
        HttpResponse(entity = HttpEntity(
          ContentTypes.`text/html(UTF-8)`,
          "<html><body>Welcome to API Application</body></html>"))


      case HttpRequest(POST, Uri.Path("/parseData"), _, entity: HttpEntity, _) =>

// Here Need to read request body which is in json format
        println("1 " + new String(entity.getDataBytes()))
        println("2 " + entity.getDataBytes())
// here need to do some calculations and again construct array of json response and send as HttpResponse
        HttpResponse(entity = "PONG!")

      case r: HttpRequest =>
        r.discardEntityBytes() // important to drain incoming HTTP Entity stream
        HttpResponse(404, entity = "Unknown resource!")
    }

    val bindingFuture = Http().bindAndHandleSync(requestHandler, "localhost", 9000)
    println(s"Server online at http://localhost:8080/\nPress RETURN to stop...")
    StdIn.readLine() // let it run until user presses return
    bindingFuture
      .flatMap(_.unbind()) // trigger unbinding from the port
      .onComplete(_ => system.terminate()) // and shutdown when done

  }
}

正如我在“ Post”请求中的上述代码中提到的那样，我需要读取请求主体数据（即json数组）并进行一些计算，最后将处理后的json数组发送到HTTPResponse。甚至尝试了高级API，但它再次陷入编组中。谁能在这方面解释或帮助我。

我尝试了以下另一种方法-

object MainController {

  // needed to run the route
  implicit val system = ActorSystem()
  implicit val materializer = ActorMaterializer()
  implicit val executionContext = system.dispatcher

  final case class hexRecord(hexstring: String)
  final case class DeviceData(hexData: List[hexRecord])
  // formats for unmarshalling and marshalling

  implicit val contentFormat = jsonFormat1(hexRecord)
  implicit val dataFormat = jsonFormat1(DeviceData)

  def main(args: Array[String]) {

    implicit val formats = org.json4s.DefaultFormats

    val requestBody = List.empty[Map[String, Any]]
    val route: Route =
      concat(
        get {
          path("welcome"){
          complete("Welcome to Parsing Application")}
        },
        post {
          path("parseDeviceData") {
            entity(as[DeviceData]) { data => {
              val result = data.hexData.map(row => {
                val parseData = ParserManager(Hex.decodeHex(row.hexstring.replaceAll("\\s", "").toCharArray))
               val jsonString = Serialization.writePretty(parseData)
                jsonString

              }).toArray 

              complete(result)
            }
            }
          }
        }
      )

    val bindingFuture = Http().bindAndHandle(route, "localhost", 9000)
    println(s"Server online at http://localhost:9000/")
    StdIn.readLine() // let it run until user presses return
    bindingFuture
      .flatMap(_.unbind()) // trigger unbinding from the port
      .onComplete(_ => system.terminate()) // and shutdown when done
  }
}

此结果在这里很好，但我在输出中得到转义字符-

[
    " {\n  \"totalsize\" : 128,\n  \"devicetypeuno\" : \"2\"} ",
    " {\n  \"totalsize\" : 128,\n  \"devicetypeuno\" : \"2\"} "
]
scala http akka akka-http
4个回答
0
投票

这是示例程序，它读取json值的数组并返回一个新的json。 

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import akka.stream.ActorMaterializer
import akka.util.Timeout
import de.heikoseeberger.akkahttpcirce.FailFastCirceSupport
import io.circe.generic.semiauto
import io.circe.{Decoder, Encoder}

import scala.concurrent.duration._
import scala.io.StdIn

object WebServer3 extends FailFastCirceSupport {

  def main(args: Array[String]) {

    implicit val system = ActorSystem("my-system")
    implicit val materializer = ActorMaterializer()
    implicit val executionContext = system.dispatcher

    implicit val timeout: Timeout = 2.seconds
    case class Zoo(foo: String, bar: String)
    case class DoneZoo(message: String)
    implicit val zooDecoder: Decoder[Zoo] = semiauto.deriveDecoder[Zoo]
    implicit val zooEncoder: Encoder[Zoo] = semiauto.deriveEncoder[Zoo]
    implicit val doneDecoder: Decoder[DoneZoo] = semiauto.deriveDecoder[DoneZoo]
    implicit val doneEnecoder: Encoder[DoneZoo] =
      semiauto.deriveEncoder[DoneZoo]

    val route = path("parseData") {
      entity(as[List[Zoo]]) { zoo =>
        zoo.foreach(println)
        complete(DoneZoo(zoo.foldLeft("") {
          case (agg, el) => agg + el.bar + el.foo + ";"
        }))
      }
    }

    val bindingFuture = Http().bindAndHandle(route, "localhost", 8080)
    println(s"Server online at http://localhost:8080/\nPress RETURN to stop...")
    StdIn.readLine()
    val _ = bindingFuture.flatMap(_.unbind())
  }
}

json是通过case类和circe semi auto derivation定义的。这将创建用于JSON转换的Encoder / Decoder类。您必须将这些类型转换为用于实体编组的Akka特定类型，这是在de.heikoseeberger.akkahttpcirce.FailFastCirceSupport的帮助下隐式完成的。

此后，您可以使用akka route dsl定义您的http路由。 entity(as[List[Zoo]])会将HTTP正文读取为json，然后返回List[Zoo]

您可以在curl的帮助下测试该应用程序>

curl -v -X POST -H 'Content-type: application/json' --data '[{"foo": "Foo", "bar": "Bar"}]' http://localhost:8080/parseData

Note: Unnecessary use of -X or --request, POST is already inferred.
*   Trying ::1...
* TCP_NODELAY set
* Connection failed
* connect to ::1 port 8080 failed: Connection refused
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8080 (#0)
> POST /parseData HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.64.1
> Accept: */*
> Content-type: application/json
> Content-Length: 30
>
* upload completely sent off: 30 out of 30 bytes
< HTTP/1.1 200 OK
< Server: akka-http/10.1.7
< Date: Tue, 15 Oct 2019 08:46:56 GMT
< Content-Type: application/json
< Content-Length: 18
<
* Connection #0 to host localhost left intact
{"message":"DONE"}* Closing connection 0


编辑：

Json序列化必须由akka在请求entity(as[])和响应complete中处理。不要手动创建JSON。

0
投票

您可以尝试这个。

0
投票

就像jsonFormat1[DeviceData]和as的组合可以帮助您将JSON字符串转换为DeviceData对象一样，您可以在另一个方向上使用相同的技术将结果转换为JSON，而无需手动编组输出。

0
投票

我使用以下方法做到了-

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