Recursive traverse JSON with circe-optics - scala

Question

I have a json with complex structure. Something like this:
{
"a":"aa",
"b":"bb",
"c":[
"aaa",
"bbb"
],
"d":{
"e":"ee",
"f":"ff"
}
}
And I want to uppercase all string values. The Documentation says:
root.each.string.modify(_.toUpperCase)
But only root values are updated, as expected.
How to make circe-optics traverse all string values recursively?
JSON structure is unknown in advance.
Here is the example on Scastie.
via comments:
I am expecting all string values uppercased, not only root values:
{
"a":"AA",
"b":"BB",
"c":[
"AAA",
"BBB"
],
"d":{
"e":"EE",
"f":"FF"
}
}

Answer 1

Here is a partial solution, as in, it is not fully recursive, but it will solve the issue with the json from your example:
val level1UpperCase = root.each.string.modify(s => s.toUpperCase)
val level2UpperCase = root.each.each.string.modify(s => s.toUpperCase)
val uppered = (level1UpperCase andThen level2UpperCase)(json.right.get)

Answer 2

The following might be a new way to do this. Adding it here for completeness.
import io.circe.Json
import io.circe.parser.parse
import io.circe.optics.JsonOptics._
import monocle.function.Plated
val json = parse(
"""
|{
| "a":"aa",
| "b":"bb",
| "c":[
| "aaa",
| {"k": "asdads"}
| ],
| "d":{
| "e":"ee",
| "f":"ff"
| }
|}
|""".stripMargin).right.get
val transformed = Plated.transform[Json] { j =>
j.asString match {
case Some(s) => Json.fromString(s.toUpperCase)
case None => j
}
}(json)
println(transformed.spaces2)
gives
{
"a" : "AA",
"b" : "BB",
"c" : [
"AAA",
{
"k" : "ASDADS"
}
],
"d" : {
"e" : "EE",
"f" : "FF"
}
}