那多个连串都有所HttpEntity类型来装载必要沟通的多少

 
我们说过Akka-http是三个好的体系融为生龙活虎体育工作具,集成是通过数据交换形式达成的。Http是个在网络传输和吸收接纳的正统协商。所以,在动用Akka-http在此以前,可能我们依然供给把Http格局的网络数据调换细节通晓通晓。数据调换双方是通过Http信息类型Request和Response来得以完结的。在Akka-http中对应的是HttpRequest和HttpResponse。那五个品类都存有HttpEntity类型来装载需求交流的数目。首先,无论怎么样数据在线上的表现格局料定是大器晚成串bytes。所以,数据沟通四头Request,Response中的Entity也必需是以bytes来抒发的。在Akka-http里大家把要求传输的多少转变来ByteString,通过互连网发送給接受端、接纳端再把收到音讯Entity中的ByteString调换到目的项目标数据。这七个转移进程正是Akka-http的马歇尔ing和Unmarshalling进程了。大家先从HttpEntity的营造函数来询问它的定义:

object HttpEntity {
  implicit def apply(string: String): HttpEntity.Strict = apply(ContentTypes.`text/plain(UTF-8)`, string)
  implicit def apply(bytes: Array[Byte]): HttpEntity.Strict = apply(ContentTypes.`application/octet-stream`, bytes)
  implicit def apply(data: ByteString): HttpEntity.Strict = apply(ContentTypes.`application/octet-stream`, data)
  def apply(contentType: ContentType.NonBinary, string: String): HttpEntity.Strict =
    if (string.isEmpty) empty(contentType) else apply(contentType, ByteString(string.getBytes(contentType.charset.nioCharset)))
  def apply(contentType: ContentType, bytes: Array[Byte]): HttpEntity.Strict =
    if (bytes.length == 0) empty(contentType) else apply(contentType, ByteString(bytes))
  def apply(contentType: ContentType, data: ByteString): HttpEntity.Strict =
    if (data.isEmpty) empty(contentType) else HttpEntity.Strict(contentType, data)

  def apply(contentType: ContentType, contentLength: Long, data: Source[ByteString, Any]): UniversalEntity =
    if (contentLength == 0) empty(contentType) else HttpEntity.Default(contentType, contentLength, data)
  def apply(contentType: ContentType, data: Source[ByteString, Any]): HttpEntity.Chunked =
    HttpEntity.Chunked.fromData(contentType, data)
...

很明显,HttpEntity能够分两大类,风流倜傥种是Strict类型的,它的data是ByteString。另生机勃勃种是UniversalEntity类型,它的多少dataBytes是Source[ByteString,Any]。无论怎么样最后在线上的或许ByteString。HttpEntity的ContentType注解了传输数据格式,有:

object ContentTypes {
  val `application/json` = ContentType(MediaTypes.`application/json`)
  val `application/octet-stream` = ContentType(MediaTypes.`application/octet-stream`)
  val `text/plain(UTF-8)` = MediaTypes.`text/plain` withCharset HttpCharsets.`UTF-8`
  val `text/html(UTF-8)` = MediaTypes.`text/html` withCharset HttpCharsets.`UTF-8`
  val `text/xml(UTF-8)` = MediaTypes.`text/xml` withCharset HttpCharsets.`UTF-8`
  val `text/csv(UTF-8)` = MediaTypes.`text/csv` withCharset HttpCharsets.`UTF-8`

  // used for explicitly suppressing the rendering of Content-Type headers on requests and responses
  val NoContentType = ContentType(MediaTypes.NoMediaType)
}

瞩目:ContentType只是豆蔻年华种备注,不影响线上数据表明情势,线上的数目恒久是ByteString。但是,在那之中的application/octet-stream类型代表数量必需是Source[ByteString,Any]。大家下边就经过顾客端的事例来领会HttpEntity。上面是多个顾客端测量试验函数:

  def runService(request: HttpRequest, rentity: RequestEntity) = {
   val futResp = for {
     entity <- Future.successful(rentity)
     resp <- Http(sys).singleRequest(
       request.copy(entity = rentity)
     )
   } yield resp

   futResp
    .andThen {
      case Success(r@HttpResponse(StatusCodes.OK, _, entity, _)) =>
        entity.dataBytes.map(_.utf8String).runForeach(println)
      case Success(r@HttpResponse(code, _, _, _)) =>
        println(s"Download request failed, response code: $code")
        r.discardEntityBytes()
      case Success(_) => println("Unable to download rows!")
      case Failure(err) => println(s"Download failed: ${err.getMessage}")

    }
  }

我们只须要对那个函数字传送入RequestEntity就能够领会再次回到Response里Entity的繁多细节了。首先大家须求服务端发送三个纯字符串Hello
World。服务端代码如下:

 } ~ path("text") {
      get {
        complete("Hello World!")
      } ~

虽然complete(“Hello
World!”)某些迷糊,可是相应complete做了些字符串到ByteString的转变。大家能够从地方这一个runService函数获得验证。上面是以这件事例的调用:

  val reqText = HttpRequest(uri = s"http://localhost:8011/text")
  runService(reqText,HttpEntity.Empty)
    .andThen{case _ => sys.terminate()}

从出示的结果能够得出runService函数中的entity.dataBytes.map(_.utf8String)已经把ByteString调换到了String,也正是说服务器端发送的Entity里的数码是ByteString。

咱俩再试着发送一些数据給服务端,然后让服务端把结果通过response
entity重返来:

    } ~ path("text") {
      get {
        complete("Hello World!")
      } ~
        post {
          withoutSizeLimit {
            extractDataBytes { bytes =>
              val data = bytes.runFold(ByteString())(_ ++ _)
              onComplete(data) { t =>
                complete(t)
              }
            }
          }
        }

咱俩看见服务端对request
entity的操作是以ByteString进行的。客商端上传后生可畏串字符的request如下:

  val postText = HttpRequest(HttpMethods.POST,uri = s"http://localhost:8011/text")
  val uploadText = HttpEntity(
    ContentTypes.`text/plain(UTF-8)`,
    // transform each number to a chunk of bytes
    ByteString("hello world again")
  )
  runService(postText,uploadText)
    .andThen{case _ => sys.terminate()}

咱俩得以见见放进entity里的数量是ByteString。

咱俩知晓Akka-http是基于Akka-Stream的,具有Reactive-Stream成效特色。下边大家就示范一下哪些进展stream的上传下载。首先定制五个Source:

  val numbers = Source.fromIterator(() =>
    Iterator.continually(Random.nextInt()))
    .map(n => ByteString(s"$n\n"))
  //make conform to withoutSizeLimit constrain
  val source = limitableByteSource(numbers)

服务端也是用HttpEntity来装载那一个Source然后经过HttpRequest传给客商端的:

  path("random") {
      get {
        complete(
          HttpEntity(
            ContentTypes.`application/octet-stream`,
            // transform each number to a chunk of bytes
            source.take(10000)
          )
        )
      } ~

大家在客商端依然用runService来分析传过来的entity。由于接到叁个重型的Source,所以必要改革一下接到格局代码:

   futResp
    .andThen {
      case Success(r@HttpResponse(StatusCodes.OK, _, entity, _)) =>
        val futEnt = entity.dataBytes.map(_.utf8String).runForeach(println)
             Await.result(futEnt, Duration.Inf) // throws if binding fails
             println("End of stream!!!")
      case Success(r@HttpResponse(code, _, _, _)) =>
        println(s"Download request failed, response code: $code")
        r.discardEntityBytes()
      case Success(_) => println("Unable to download rows!")
      case Failure(err) => println(s"Download failed: ${err.getMessage}")

    }

用下边包车型客车艺术调用:

  val reqRandom = HttpRequest(uri = s"http://localhost:8011/random")
    runService(reqRandom,HttpEntity.Empty)
     .andThen{case _ => sys.terminate()}

再示范一下在顾客端用Source上传数据。服务端代码:

       post {
          withoutSizeLimit {
            extractDataBytes { bytes =>
              val data = bytes.runFold(ByteString())(_ ++ _)
              onComplete(data) { t =>
                complete(t)
              }
            }
          }
        }

客商端上传数据楷模:

 val numbers = Source.fromIterator(() =>
    Iterator.continually(Random.nextInt()))
    .map(n => ByteString(s"$n\n"))
  //make conform to withoutSizeLimit constrain
  val source = limitableByteSource(numbers)

  val bytes = HttpEntity(
    ContentTypes.`application/octet-stream`,
    // transform each number to a chunk of bytes
    source.take(10000)
  )
  val postRandom = HttpRequest(HttpMethods.POST,uri = s"http://localhost:8011/random")
  runService(postRandom,bytes)
    .andThen{case _ => sys.terminate()}

从地方研究大家询问了在马尔斯hal,Unmarshal下层只是ByteString的操作和转移。下边是本次切磋示范源代码:

服务端:

import akka.actor._
import akka.stream._
import akka.stream.scaladsl._
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import akka.http.scaladsl.model._
import akka.util.ByteString
import akka.http.scaladsl.model.HttpEntity._

import scala.util.Random

object ServerEntity extends App {

  implicit val httpSys = ActorSystem("httpSystem")
  implicit val httpMat = ActorMaterializer()
  implicit val httpEC = httpSys.dispatcher


  val numbers = Source.fromIterator(() =>
    Iterator.continually(Random.nextInt()))
    .map(n => ByteString(s"$n\n"))
  //make conform to withoutSizeLimit constrain
  val source = limitableByteSource(numbers)



  val route =
    path("random") {
      get {
        withoutSizeLimit {
          complete(
            HttpEntity(
              ContentTypes.`application/octet-stream`,
              // transform each number to a chunk of bytes
              source.take(1000))
          )
        }
      } ~
        post {
          withoutSizeLimit {
            extractDataBytes { bytes =>
              val data = bytes.runFold(ByteString())(_ ++ _)
              onComplete(data) { t =>
                complete(t)
              }
            }
          }
        }
    } ~ path("text") {
      get {
        complete("Hello World!")
      } ~
        post {
          withoutSizeLimit {
            extractDataBytes { bytes =>
              val data = bytes.runFold(ByteString())(_ ++ _)
              onComplete(data) { t =>
                complete(t)
              }
            }
          }
        }
    }


  val (port, host) = (8011,"localhost")

  val bindingFuture = Http().bindAndHandle(route,host,port)

  println(s"Server running at $host $port. Press any key to exit ...")

  scala.io.StdIn.readLine()

  bindingFuture.flatMap(_.unbind())
    .onComplete(_ => httpSys.terminate())

}

客户端:

import akka.actor._
import akka.stream._
import akka.stream.scaladsl._
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.HttpEntity.limitableByteSource
import akka.http.scaladsl.model._

import scala.concurrent.duration._
import akka.util.ByteString

import scala.concurrent._
import scala.util._

object ClientEntity extends App {

  implicit val sys = ActorSystem("ClientSys")
  implicit val mat = ActorMaterializer()
  implicit val ec = sys.dispatcher

  def runService(request: HttpRequest, rentity: RequestEntity) = {
   val futResp = for {
     entity <- Future.successful(rentity)
     resp <- Http(sys).singleRequest(
       request.copy(entity = rentity)
     )
   } yield resp

   futResp
    .andThen {
      case Success(r@HttpResponse(StatusCodes.OK, _, entity, _)) =>
        val futEnt = entity.dataBytes.map(_.utf8String).runForeach(println)
             Await.result(futEnt, Duration.Inf) // throws if binding fails
             println("End of stream!!!")
      case Success(r@HttpResponse(code, _, _, _)) =>
        println(s"Download request failed, response code: $code")
        r.discardEntityBytes()
      case Success(_) => println("Unable to download rows!")
      case Failure(err) => println(s"Download failed: ${err.getMessage}")

    }
  }

  val reqText = HttpRequest(uri = s"http://localhost:8011/text")
//  runService(reqText,HttpEntity.Empty)
//    .andThen{case _ => sys.terminate()}

  val postText = HttpRequest(HttpMethods.POST,uri = s"http://localhost:8011/text")
  val uploadText = HttpEntity(
    ContentTypes.`text/plain(UTF-8)`,
    // transform each number to a chunk of bytes
    ByteString("hello world again")
  )
//  runService(postText,uploadText)
//    .andThen{case _ => sys.terminate()}

  val reqRandom = HttpRequest(uri = s"http://localhost:8011/random")
 //   runService(reqRandom,HttpEntity.Empty)
 //    .andThen{case _ => sys.terminate()}

  val numbers = Source.fromIterator(() =>
    Iterator.continually(Random.nextInt()))
    .map(n => ByteString(s"$n\n"))
  //make conform to withoutSizeLimit constrain
  val source = limitableByteSource(numbers)

  val bytes = HttpEntity(
    ContentTypes.`application/octet-stream`,
    // transform each number to a chunk of bytes
    source.take(10000)
  )
  val postRandom = HttpRequest(HttpMethods.POST,uri = s"http://localhost:8011/random")
  runService(postRandom,bytes)
    .andThen{case _ => sys.terminate()}


}