How to ignore JsonNulls with a Circe Cursor

Question

I am processing json in which one of the keys values, values2, or values3 will be a JsonObject, and the other two will be null.

Is there any way to create a cursor such that when attempting to downField on a json null, the resulting cursor is a failed one?

Hopefully the code example and the commented line make it clear what i'm trying to achieve here.

object Foo extends App {
  import io.circe._, io.circe.parser._
  val json: String = """
      {
        "id": "c730433b-082c-4984-9d66-855c243266f0",
        "values": {
          "bar": true,
          "baz": 100.001
        },
        "values2": null
      }
    """

  val doc: Json = parse(json).getOrElse(Json.Null)
  val rootCursor = doc.hcursor
  val result = for {
    name <- rootCursor.downField("id").as[String] 
    valuesCursor = rootCursor.downField("values")
    values2Cursor = rootCursor.downField("values2")
  } yield {
     if (values2Cursor.succeeded) { // I want this to be false when values2 -> JNull
       2
     } else {
       1
     }
  }
}

Answer 1

Try dropNullValues like so

...
parse(json).getOrElse(Json.Null).dropNullValues
...

which outputs result: scala.util.Either[io.circe.DecodingFailure,Int] = Right(1)