Consider the following JSON
{
"a": "{\"b\": 12, \"c\": \"test\"}"
}
I would like to define a generic reads Reads[Outer[T]]
for this kind of serialized Json
import play.api.libs.json.{Json, Reads, __}
final case class Outer[T](inner: T)
final case class SpecializedInner(b: Int, c: String)
object SpecializedInner {
implicit val reads: Reads[SpecializedInner] = Json.reads[SpecializedInner]
}
object Outer {
implicit def reads[T](implicit readsT: Reads[T]): Reads[Outer[T]] = ???
}
How can I achieve my goal? I tried to flatMap a string-reads for the field "outer.a" but got stuck since I am not able to produce a Reads[T] from the validated JSON
object Outer {
implicit def reads[T](implicit readsT: Reads[T]): Reads[Outer[T]] =
(__ \ "a").read[String].flatMap(x => Json.parse(x).validate[T])
}