AkkaHTTP：从HttpEntity中获取内容 [英] AkkaHTTP: Getting content out of an HttpEntity

问题描述

我正在Scala中使用AkkaHTTP，试图与API进行交互，但是在通过某些API调用获取数据时遇到了一些麻烦。基本上，我有一个curl命令，该命令在终端中可用于对该特定API的任何有效API调用，但是在我的当前代码中，我仅获得响应足够小的调用的实际数据。

I'm working with AkkaHTTP in Scala, trying to interact with an API, but I'm having some trouble getting data with certain API calls. Basically, I have a curl command which works in my terminal for any valid API call to this certain API, but in my current code I only get the actual data for calls whose responses are small enough.

我的第一次尝试是使用sys.process._和!! curl（url）-X GET -H \授权：承载（身份验证令牌）：（这是在我的终端上运行的命令）上的字符串的方法，但是由于以下原因导致scala错误并失败问题是解析标头；因此，在没有任何进展并意识到无论如何我都想使用AkkaHTTP之后，我放弃了这种方法，来到下面的代码，我从另一个stackoverflow帖子借来的格式。

My first attempt was using sys.process._ and the !! method on a string with "curl (url) -X GET -H \"Authorization: Bearer (auth token)\" (which is the command that works in my terminal), but that failed with an error in scala due to issues parsing the header; so after making no headway on that and realizing I wanted to use AkkaHTTP anyway, I abandoned that approach and came to the code below, whose format I borrowed from another stackoverflow post.

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

val responseFuture: Future[HttpResponse] = Http().singleRequest(HttpRequest(
  uri = "(url)").withHeaders(
  RawHeader("Authorization", "Bearer (auth token)")
))


responseFuture
  .onComplete {
    case Success(res) => println(res)
    case Failure(_)   => "failure"
  }

现在，我已经尝试过两个不同的API调用；首先，在我的终端中返回一个327个字符的JSON字符串，然后返回一个blob，其中res.entity是HttpEntity.Strict（application / json，（与终端中的JSON Blob相同））。但是，尽管第二个调用在我的终端中返回了一个203,413个字符的JSON Blob（比第一个大得多），但是在scala中发送该请求会返回一个blob，其中res.entity只是HttpEntity.Chunked（application / json）。我想将有效负载拆分为多个数据包（ Chunked是该情况的一个相当适用的名称），但是我似乎无法弄清楚如何从此处获取有效负载信息，我希望能有所帮助。

Now, I've tried this on two different API calls; the first, which in my terminal returns a JSON string with 327 characters, returns a blob, where res.entity is HttpEntity.Strict(application/json,(the same JSON blob as in the terminal)). However, while the second call returns in my terminal a JSON blob with 203,413 characters (much bigger than the first one), sending that request in scala returns a blob where res.entity is just HttpEntity.Chunked(application/json). I would presume the payload is split into multiple packets ("Chunked" being a fairly applicable name for that scenario), but I can't seem to figure out how to get the payload information from here, and I'd appreciate some help.

推荐答案

如果可以将整个实体加载到内存中，则可以调用 toStrict ResponseEntity ：

If it's acceptable to load the entire entity into memory, you can call toStrict on the ResponseEntity:

import scala.concurrent.Future
import scala.concurrent.duration._

val entityFut: Future[String] =
  responseFuture.flatMap(_.entity.toStrict(5 seconds).map(_.data.utf8String))

entityFut.onComplete {
  case Success(body) =>
    println(body)
  case Failure(_) =>
    println("failure")
}

您还可以使用内置的-in unmarshaller ：

You could also use a built-in unmarshaller:

import akka.http.scaladsl.unmarshalling.Unmarshal

val entityFut: Future[String] =
  responseFuture.flatMap(resp => Unmarshal(resp.entity).to[String])

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