[英]Circe - Use default fields in case class when decoding/encoding json
[英]Decoding Json with Circe when fields are incomplete
我有一個json格式的成績單,里面有很多字
{
"words": [{
"duration": 123,
"name": "world"
"time": 234,
"speaker": null
}]
}
我一直在使用Circe編碼/解碼Json。 在這種情況下:
import io.circe.generic.auto._
import io.circe.parser._
val decoded = decode[Transcript](transcriptJson)
我的ADT看起來像:
case class Word(
duration: Double,
name: String,
time: Float,
para: String,
speaker: Option[String],
key: Option[String] = None,
strike: Option[String] = None,
highlight: Option[String] = None
)
case class Transcript(words: List[Word])
有時,單詞具有“ strike”或“ highlight”之類的鍵,但很可能沒有。 如果沒有,我會收到以下錯誤消息。
Left(DecodingFailure([A]List[A], List(DownField(highlight), MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, MoveRight, DownArray, DownField(words))))
當“單詞”沒有所有字段時,正確解碼它的最佳方法是什么?
正如Travis Brown在Gitter上指出的那樣:
“這可以與通用擴展一起使用:”
import io.circe.generic.extras.Configuration
implicit val config: Configuration = Configuration.default.withDefaults
(加上para的默認值並import io.circe.generic.extras.auto._
)
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