Question

我正在使用遗留的HTTP API（我无法更改），它在正文中以JSON响应，但提供了Content-Type: text/plain; charset=utf-8标题。

我试图将HTTP主体解组为JSON，但我得到以下异常：akka.http.scaladsl.unmarshalling.Unmarshaller$UnsupportedContentTypeException: Unsupported Content-Type, supported: application/json

我的代码如下所示：

import spray.json.DefaultJsonProtocol
import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport._
import akka.http.scaladsl.unmarshalling._

case class ResponseBody(status: String, error_msg: String)

object ResponseBodyJsonProtocol extends DefaultJsonProtocol {
  implicit val responseBodyFormat = jsonFormat2(ResponseBody)
}

def parse(entity: HttpEntity): Future[ResponseBody] = {
  implicit val materializer: Materializer = ActorMaterializer()
  import ResponseBodyJsonProtocol._
  Unmarshal[HttpEntity](entity).to[ResponseBody]
}

示例HTTP响应如下所示：

HTTP/1.1 200 OK
Cache-Control: private
Content-Encoding: gzip
Content-Length: 161
Content-Type: text/plain; charset=utf-8
Date: Wed, 16 Dec 2015 18:15:14 GMT
Server: Microsoft-IIS/7.5
Vary: Accept-Encoding
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET

{"status":"1","error_msg":"Missing parameter"}

如何忽略HTTP响应中的Content-Type并解析为JSON？

Answer 1

我发现的一个解决方法是在解组之前在HttpEntity上手动设置def parse(entity: HttpEntity): Future[ResponseBody] = { implicit val materializer: Materializer = ActorMaterializer() import ResponseBodyJsonProtocol._ Unmarshal[HttpEntity](entity.withContentType(ContentTypes.`application/json`)).to[ResponseBody] }：

for /R "%zipFilePath%" %%I in ("*.zip") do (
  "C:\Program Files\7-Zip\7z.exe" x -y -o"%%~dpI" "%%~fI" 
)

似乎工作正常，但我对其他想法持开放态度......

Answer 2

我使用map...指令。它看起来简短而优雅。

val routes = (decodeRequest & encodeResponse) {
  mapResponseEntity(_.withContentType(ContentTypes.`application/json`)) {
    nakedRoutes ~ authenticatedRoutes
  }
}

Answer 3

另一种解决方案：创建一个接受任何内容类型（或任何内容类型列表）的自定义解组器：

import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport.sprayJsValueByteStringUnmarshaller
import akka.http.scaladsl.model.ContentTypeRange
import akka.http.scaladsl.unmarshalling.{FromEntityUnmarshaller, Unmarshaller}
import spray.json.{RootJsonReader, jsonReader}

// Add this to scope, INSTEAD OF importing SprayJsonSupport._
// It returns an Unmarshaller identical to SprayJsonSupport.sprayJsonUnmarshaller, but with a custom validation on content type
implicit def lenientJsonUnmarshaller[T](implicit reader: RootJsonReader[T]): FromEntityUnmarshaller[T] =
  Unmarshaller.byteStringUnmarshaller
    .forContentTypes(ContentTypeRange.*) // or any range you'd like
    .andThen(sprayJsValueByteStringUnmarshaller)
    .map(jsonReader[T].read)

然后 - 在范围内，继续你所做的：

def parse(entity: HttpEntity): Future[ResponseBody] = {
  implicit val materializer: Materializer = ActorMaterializer()
  import ResponseBodyJsonProtocol._
  Unmarshal[HttpEntity](entity).to[ResponseBody] // this implicitly uses the custom unmarshaller
}

好处 - 很容易重用这个隐式解组器 - 编写一次，只需在任何需要的地方导入，而不必在实体上设置内容类型。

如何在Akka HTTP中将`text / plain`解组为JSON

3 个答案: