Is there any simpler approach to provided a default value for un-suppiled or blank string field when parsing JSON with argonaut?

Question

I'm using Argonaut to parse JSON strings. There is a requirement: If any field is not provided, or is empty or blank, give it the string "not supplied" instead.

I have a solution, but it seems very complicated:

case class User(name: String, home: String)

implicit def UserDecodeJson: DecodeJson[User] = DecodeJson(j => for {
  name <- (j --\ "name").as[BlankAsNonSupplied]
  home <- (j --\ "home").as[BlankAsNonSupplied]
} yield User(name.value, home.value))

case class BlankAsNonSupplied(value: String)

implicit def BlankAsNonSuppliedDecodeJson: DecodeJson[BlankAsNonSupplied] = DecodeJson.withReattempt(a => {
  val v = a.success.map(_.focus).flatMap(_.string)
    .filterNot(_.trim.isEmpty)
    .map(BlankAsNonSupplied.apply).getOrElse(BlankAsNonSupplied("not supplied"))
  DecodeResult.ok(v)
})

You can see the BlankAsNonSuppliedDecodeJson one is very complicated, and hard to understand. Is there any way to make it(or the whole example) simpler?

Is there any simpler approach to provided a default value for un-suppiled or blank string field when parsing JSON with argonaut?

0 Answers0