Validation Only With Play Json - scala

Question

I'd like to use PlayJson to only validate multiple fields of some json and not map it to a custom object. I Only care about the Yes Or No answer to the validation criteria. Is it possible to use PlayJson in that way? So far I have something like,
val json = .....
val reads = (JsPath \ "foo").read[String](min(5)) and
(JsPath \ "bar").read[String](max(10))
json.validate["I ONLY WANT TO VALIDATE NOT MAP"](reads) match {
case s: JsSuccess => true
case e: JsError => false
}
Thank you Stack Overflow community.

Answer 1

Instead of deserialising to a case class model via Reads[MyModel] we can deserialise to a tuple via Reads[(String, String)] like so
import play.api.libs.json._
import play.api.libs.json.Reads._
import play.api.libs.functional.syntax._
val reads = (
(JsPath \ "foo").read[String](minLength[String](5)) and
(JsPath \ "bar").read[String](minLength[String](10))
).tupled
val json = Json.parse(
"""
|{
| "foo": "abcde",
| "bar": "woohoowoohoo",
| "zar": 42
|}
|""".stripMargin)
json.validate(reads).isSuccess
which outputs
res0: Boolean = true
Note how we called tupled method when creating the reader, and isSuccess to get a boolean out of validation process.
https://scalafiddle.io/sf/JBjdt2Y/0