How to replace value in json using scala play json

Question

I'm at scala play 2.6.10 I have a json:

{"_id": {"$oid": "VALUE"}, "anotherField": "anotherValue"}

The goal is to get rid of {"$oid": "VALUE"} and put "VALUE" as the value for "_id" field.

Expected result:

{"_id": "VALUE", "anotherField": "anotherValue"}

Tried this one: https://www.playframework.com/documentation/2.8.x/ScalaJsonTransformers

i have absolutely no idea how to combine

extract specific branch value
"prune" of JsObject
"update" deleted JsObject with JsString.

BTW, is there any simpler API for doing it? This one is way too complex.

I've seen similar examples. Can't make it work since I "update" JsObject to JsString. Don't understand how to express it with that Json DSL — Capacytron, Mar 09 '21 at 13:35
Look like MongoDB extended syntax, so rather use a dedicated lib — cchantep, Mar 09 '21 at 22:41
what is dedicated lib? can mongo-scala-driver interact with scala case classes directly? — Capacytron, Mar 10 '21 at 14:41
http://reactivemongo.org/releases/1.0/documentation/json/overview.html#documents-and-values — cchantep, Mar 10 '21 at 14:56
Does this answer your question? [How to update a nested json using scala play framework?](https://stackoverflow.com/questions/64280699/how-to-update-a-nested-json-using-scala-play-framework) — Oleg Pyzhcov, Mar 12 '21 at 08:03

score 2 · Accepted Answer · answered Mar 09 '21 at 13:44

You can read more about the update documentation at How to update a nested json using scala play framework? In your example you can do something like this:

val jsonString = """{"_id": {"$oid": "VALUE"}, "anotherField": "anotherValue"}
                   |""".stripMargin

val jsonTransformer = (__ \ "_id").json.update(__.read[JsObject].map { _ => JsString("Value") })
Json.parse(jsonString).transform(jsonTransformer) match {
  case JsSuccess(value, _) =>
    println(value)
  case JsError(errors) =>
    println(errors)
}

It outputs:

{"anotherField":"anotherValue","_id":"Value"}

Code run at Scastie.

How to replace value in json using scala play json

1 Answers1