我试图分析来自Akka的HttpResponse
。理想的行为是,如果响应成功返回,则传递Array[Byte]
的HttpEntity
表示以进行处理。但是,如果状态返回为失败,则传递带有异常的Future.failed
,其中包含状态代码和HttpEntity
的JSON树表示。传递JSON树的原因是这个抽象请求方法有不同的服务器,并且它们的响应格式不同,所以我想在其他类中处理响应的解析。
我尝试过对这个工作流程的各种操作。直接抛出异常而不是返回Future.failed
会返回None
值来代替异常中的JSON树。其他方法产生类似的结果。当我println(MAPPER.readTree(byteArray))
它按照我的预期打印出响应,但然后继续返回None
在response
的BadRequestException
字段。
import akka.http.scaladsl.model._
import akka.http.scaladsl.model.headers.Authorization
import akka.stream.Materializer
import com.fasterxml.jackson.databind.{DeserializationFeature, JsonNode, ObjectMapper}
import com.fasterxml.jackson.module.scala.DefaultScalaModule
import com.fasterxml.jackson.module.scala.experimental.ScalaObjectMapper
val MAPPER = new ObjectMapper with ScalaObjectMapper
MAPPER.registerModule(DefaultScalaModule)
MAPPER.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
def performQueryRaw(method: HttpMethod, uri: Uri, entity: Option[RequestEntity] = None, authorization: Option[Authorization] = None): Future[Array[Byte]] = {
val request: HttpRequest = HttpRequest(
method = method,
uri = uri,
entity = entity.getOrElse(HttpEntity.Empty),
headers = authorization.toList)
http.singleRequest(request).transformWith[Array[Byte]] {
case Success(response: HttpResponse) =>
convertEntityToBytes(response.entity).map { byteArray =>
if (response.status.isFailure()) Future.failed(BadRequestException(response.status, MAPPER.readTree(byteArray)))
else byteArray
}
case Failure(throwable) => Future.failed(RequestFailedException(throwable.getMessage + " -- " + uri.toString, throwable))
}
}
def convertEntityToBytes(entity: HttpEntity): Future[Array[Byte]] = {
entity.dataBytes.runFold[Seq[Array[Byte]]] (Nil) {
case (acc, next) => acc :+ next.toArray
}.map(_.flatten.toArray)
}
case class BadRequestException(status: StatusCode, response: JsonNode = None.orNull, t: Throwable = None.orNull) extends Exception(t)
case class RequestFailedException(message: String, t: Throwable = None.orNull) extends Exception(message, t)
我期待一个BadRequestException
输出JsonNode的非none值。相反,我在Future.failed
上遇到编译器错误:
Expression of type Future[Nothing] doesn't conform to expected type Array[Byte]
。
任何帮助将不胜感激。
在flatMap
之后运行下一步时使用map
而不是convertEntityToBytes
:
def performQueryRaw(
method: HttpMethod,
uri: Uri,
entity: Option[RequestEntity] = None,
authorization: Option[Authorization] = None
): Future[Array[Byte]] = {
val request: HttpRequest = HttpRequest(
method = method,
uri = uri,
entity = entity.getOrElse(HttpEntity.Empty),
headers = authorization.toList
)
Http().singleRequest(request).transformWith[Array[Byte]] {
case Success(response: HttpResponse) =>
convertEntityToBytes(response.entity).flatMap { byteArray =>
if (response.status.isFailure()) Future.failed(new Exception("change this exception to one you had"))
else Future.successful(byteArray)
}
case Failure(throwable) => Future.failed(new Exception("also here"))
}
}
既然你想失败你Future
计算,你需要返回新的Future
。如果失败,你一直在做Future.failed
。缺少的部分也是将一个byteArray包装到Future.successful
。当然这是解决此代码中类型编译错误的方法之一。