Использование Lift-Json с классами Case

Question

Использование Lift-Json с классами Case

Кажется, я не могу написать надлежащие классы case для этой конкретной полезной нагрузки Json. Я считаю, что это как-то связано с первым индексом в массиве, который не имеет ключевой строки. Есть идеи, как это исправить? Для справки я использую Scala 2.10.4, Akka 2.3.2, Spray 1.3.1 и Lift-Json 2.6. Json, который я пытаюсь извлечь, взят из API событий Mailgun. Изменить: основной вопрос заключается в том, как извлечь из класса дела без ключа в Json? Мой код выглядит следующим образом:

import net.liftweb.json._

case class Paging(next : String, previous : String)
case class DeliveryEnvelope(transport : String, sender : String, `sending-ip` : String)
case class DeliveryIndex(tags : List[String], envelope : DeliveryEnvelope)
case class DeliveryStatus(message : String, code : Int, description : String)
case class Flags(`is-authenticated` : Boolean, `is-test-mode` : Boolean)
case class DeliveryMessage(headers : Headers, attachments : Option[List[Object]], recipients : List[String], size : Long)
case class Headers(to : String, `message-id` : String, from : String, subject : String)
case class DeliveryData(index : DeliveryIndex, `delivery-status` : DeliveryStatus,
                    campaigns : List[String], `user-variables` : Object, flags : Flags, timestamp : Double,
                    message : DeliveryMessage, recipient : String, event : String)
case class Delivered(items: List[DeliveryData], paging: Paging)

object Main extends App {
  implicit val formats = DefaultFormats

val json = parse(
""" {
  "items": [
    {
      "tags": [],
      "envelope": {
        "transport": "smtp",
        "sender": "postmaster@samples.mailgun.org",
        "sending-ip": "184.173.153.199"
      },
      "delivery-status": {
        "message": "",
        "code": 0,
        "description": null
      },
      "campaigns": [],
      "user-variables": {},
      "flags": {
        "is-authenticated": true,
        "is-test-mode": false
      },
      "timestamp": 1377208314.173742,
      "message": {
        "headers": {
          "to": "recipient@example.com",
          "message-id": "20130822215151.29325.59996@samples.mailgun.org",
          "from": "sender@example.com",
          "subject": "Sample Message"
        },
        "attachments": [],
        "recipients": [
          "recipient@example.com"
        ],
        "size": 31143
      },
      "recipient": "recipient@example.com",
      "event": "delivered"
    }
  ],
  "paging": {
    "next": "https://api.mailgun.net/v2/samples.mailgun.org/events/W3siYiI6ICIy",
    "previous": "https://api.mailgun.net/v2/samples.mailgun.org/events/W3siYiI6"
  }
} """)
println(compactRender(json))
println(json.extract[Delivered])

И вывод:

{"items":[{"tags":[],"envelope":{"transport":"smtp","sender":"postmaster@samples.mailgun.org","sending-ip":"184.173.153.199"},"delivery-status":{"message":"","code":0,"description":null},"campaigns":[],"user-variables":{},"flags":{"is-authenticated":true,"is-test-mode":false},"timestamp":1.377208314173742E9,"message":{"headers":{"to":"recipient@example.com","message-id":"20130822215151.29325.59996@samples.mailgun.org","from":"sender@example.com","subject":"Sample Message"},"attachments":[],"recipients":["recipient@example.com"],"size":31143},"recipient":"recipient@example.com","event":"delivered"}],"paging":{"next":"https://api.mailgun.net/v2/samples.mailgun.org/events/W3siYiI6ICIy","previous":"https://api.mailgun.net/v2/samples.mailgun.org/events/W3siYiI6"}}
Exception in thread "main" net.liftweb.json.MappingException: No usable value for items
No usable value for index
No usable value for envelope
No usable value for transport
Did not find value which can be converted into java.lang.String
   at net.liftweb.json.Meta$.fail(Meta.scala:191)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:357)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:317)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
   at scala.collection.AbstractTraversable.map(Traversable.scala:105)
   at net.liftweb.json.Extraction$.instantiate$1(Extraction.scala:253)
   at net.liftweb.json.Extraction$.newInstance$1(Extraction.scala:286)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:315)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$extract0(Extraction.scala:366)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$extract0(Extraction.scala:199)
   at net.liftweb.json.Extraction$.extract(Extraction.scala:43)
   at net.liftweb.json.JsonAST$JValue.extract(JsonAST.scala:312)
   at Main$delayedInit$body.apply(Main.scala:87)
   at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
   at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
   at scala.App$$anonfun$main$1.apply(App.scala:71)
   at scala.App$$anonfun$main$1.apply(App.scala:71)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
   at scala.App$class.main(App.scala:71)
   at Main$.main(Main.scala:30)
   at Main.main(Main.scala)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
   at java.lang.reflect.Method.invoke(Method.java:606)
   at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: net.liftweb.json.MappingException: No usable value for index
No usable value for envelope
No usable value for transport
Did not find value which can be converted into java.lang.String
   at net.liftweb.json.Meta$.fail(Meta.scala:191)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:357)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:317)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
   at scala.collection.AbstractTraversable.map(Traversable.scala:105)
   at net.liftweb.json.Extraction$.instantiate$1(Extraction.scala:253)
   at net.liftweb.json.Extraction$.newInstance$1(Extraction.scala:286)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:315)
   at net.liftweb.json.Extraction$$anonfun$21.apply(Extraction.scala:305)
   at net.liftweb.json.Extraction$$anonfun$21.apply(Extraction.scala:305)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
   at scala.collection.AbstractTraversable.map(Traversable.scala:105)
   at net.liftweb.json.Extraction$.newCollection$1(Extraction.scala:305)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:322)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 30 more
Caused by: net.liftweb.json.MappingException: No usable value for envelope
No usable value for transport
Did not find value which can be converted into java.lang.String
   at net.liftweb.json.Meta$.fail(Meta.scala:191)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:357)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:317)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
   at scala.collection.AbstractTraversable.map(Traversable.scala:105)
   at net.liftweb.json.Extraction$.instantiate$1(Extraction.scala:253)
   at net.liftweb.json.Extraction$.newInstance$1(Extraction.scala:286)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:315)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 51 more
Caused by: net.liftweb.json.MappingException: No usable value for transport
Did not find value which can be converted into java.lang.String
   at net.liftweb.json.Meta$.fail(Meta.scala:191)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:357)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:317)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at net.liftweb.json.Extraction$$anonfun$14.apply(Extraction.scala:253)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
   at scala.collection.immutable.List.foreach(List.scala:318)
   at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
   at scala.collection.AbstractTraversable.map(Traversable.scala:105)
   at net.liftweb.json.Extraction$.instantiate$1(Extraction.scala:253)
   at net.liftweb.json.Extraction$.newInstance$1(Extraction.scala:286)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:315)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 63 more
Caused by: net.liftweb.json.MappingException: Did not find value which can be converted into java.lang.String
   at net.liftweb.json.Meta$.fail(Meta.scala:191)
   at net.liftweb.json.Extraction$.convert(Extraction.scala:403)
   at net.liftweb.json.Extraction$.net$liftweb$json$Extraction$$build$1(Extraction.scala:314)
   at net.liftweb.json.Extraction$.mkValue$1(Extraction.scala:351)
... 75 more

1

json scala mailgun lift lift-json

Источник

user3934300 14 авг '14 в 03:17

2 ответа

Другие вопросы по тегам json scala mailgun lift lift-json

user3934300 16 авг '14 в 08:41 2014-08-16 08:41 · Answer 1 · 2014-08-16 08:41

Спасибо всем за помощь (или просто просмотр) моего вопроса. Я решил свою проблему, просматривая только часть данных Json.

val json = parse(STRING HERE)
      val elements = (json \\ "items").children
      for(item <- elements) {
        val data = item.extract[ClickData]

Надеюсь, это поможет кому-то еще с этим или похожим вопросом.

user829752 14 авг '14 в 14:26 2014-08-14 14:26 · Answer 2 · 2014-08-14 14:26

Вы сопоставляете каждый элемент с экземпляром DeliveryData, но в DeliveryData:

У вас есть необязательное поле индекса, для которого нет значения в соответствующем JSON. Если это значение является необязательным, оно должно быть определено как Option[DeliveryIndex]
У вас нет поля для сопоставления информации о конверте, содержащейся в JSON. Вы создали класс случая DeliveryEnvelope, но на него ссылается только класс DeliveryIndex, а поле индекса не существует в опубликованном вами JSON.