Circe Unmarshall HttpResponse

Question

我正在向领事寻求健康的服务。回应是：

HttpResponse(200 OK,List(X-Consul-Index: 3471242, X-Consul-Knownleader: true, X-Consul-Lastcontact: 0, Date: Fri, 02 Mar 2018 16:06:08 GMT),HttpEntity.Strict(application/json,[{"Node":{"Node":"ci-content-1","Address":"10.45.200.14","TaggedAddresses":{"wan":"10.45.200.14"},"CreateIndex":2708577,"ModifyIndex":3470978},"Service":{"ID":"de62bdcb8e37:varnish_2:6085","Service":"shop-varnish-6085","Tags":null,"Address":"10.45.200.14","Port":33889,"EnableTagOverride":false,"CreateIndex":3313055,"ModifyIndex":3313055},"Checks":[{"Node":"ci-content-1","CheckID":"serfHealth","Name":"Serf Health Status","Status":"passing","Notes":"","Output":"Agent alive and reachable","ServiceID":"","ServiceName":"","CreateIndex":2708577,"ModifyIndex":3451134}]},{"Node":{"Node":"ci-content-2","Address":"10.45.200.18","TaggedAddresses":{"wan":"10.45.200.18"},"CreateIndex":2158463,"ModifyIndex":3471241},"Service":{"ID":"f89a94600d4c:varnish_1:6085","Service":"shop-varnish-6085","Tags":null,"Address":"10.45.200.18","Port":33622,"EnableTagOverride":false,"CreateIndex":3313064,"ModifyIndex":3313064},"Checks":[{"Node":"toom-ci-content-2","CheckID":"serfHealth","Name":"Serf Health Status","Status":"passing","Notes":"","Output":"Agent alive and reachable","ServiceID":"","ServiceName":"","CreateIndex":2158464,"ModifyIndex":3297480}]}]

类定义是：

final case class TaggedAddresses (
  wan: String)

final case class Node (
  node: String,
  address: String,
  taggedAddresses: TaggedAddresses,
  createIndex: Int,
  modifyIndex: Int
)

final case class Service (
  id: String,
  service: String,
  tags: String,
  addresses: String,
  port: Int,
  enableTagOverride: String,
  createIndex: Int,
  modifyIndex: Int
)

final case class Check (
  node: String,
  checkId:String,
  name: String,
  status: String,
  notes: String,
  output: String,
  serviceId: String,
  serviceName:String,
  createIndex: Int,
  modifyIndex: Int
)

final case class NodeInfo(
  node: Node,
  service: Service,
  checkList: List[Check]
)

package object VarnishInformation {}

然后我尝试解组：

val request = HttpRequest(method = HttpMethods.GET, uri = consulUrl)

val response = Await.result(Http().singleRequest(request), 10.seconds)

log.info("Entity: " + response.httpMessage)

val entries = Unmarshal(response).to[List[NodeInfo]]

并得到以下错误：

处理请求时出错：'尝试解码失败的游标上的值：DownField（节点），DownArray'。完成500内部服务器错误响应。要更改默认的异常处理行为，请提供自定义的ExceptionHandler。

我看不到失败，其他任何人都可以做到？

Answer 1

简短的回答：假设你已经安装了所有必需的解码器和编码器，你应该简单地修改你的case类，如下所示：

case class Node (
  Node: String,
  Address: String,
  TaggedAddresses: TaggedAddresses,
  CreateIndex: Int,
  ModifyIndex: Int
)

即，您必须使用与JSON中显示的标记名称完全相同的标记名称。

答案很长：如果我从你的对象中取出相关的JSON，如下所示：

val jsonString = 
"""
{
   "Node":{
     "Node":"ci-content-1",
     "Address":"10.45.200.14",
     "TaggedAddresses":{
       "wan":"10.45.200.14"
     },
   "CreateIndex":2708577,
   "ModifyIndex":3470978
 },
 ...
"""

然后，当使用上述更正版本的case类时，以下代码将产生Right(Node(ci-content-1,10.45.200.14,TaggedAddresses(10.45.200.14),2708577,3470978))：

def myParse(jsonString: String) = {
  val res = parse(jsonString) match {
    case Right(json) => {
      val cursor = json.hcursor
      cursor.get[Node]("Node")
    }
    case _ => Left("Wrong JSON!") 
  }

  println(res)
}

否则，我也会得到您描述的相同错误。