refinedDecoder

refinedDecoder.scala

package mf.refined

import eu.timepit.refined.auto._
import eu.timepit.refined._
import eu.timepit.refined.api.{Refined, RefType}
import eu.timepit.refined.collection._
import eu.timepit.refined.numeric._
import io.circe._, io.circe.generic.semiauto._
import io.circe.syntax._
import cats.implicits._
import cats.syntax.either
import io.circe.{ Decoder, Encoder }
import io.circe.parser.decode

case class UserName(val name: String Refined NonEmpty, val age: Int Refined Positive)
case class SimpleUserName(val name: String, val age: Int)
case object UserName {

    // implicit val userNameDecoder: Decoder[UserName] = deriveDecoder[UserName]
    // implicit val userNameEncoder: Encoder[UserName] = deriveEncoder[UserName]

    implicit val userDecoder: Decoder[UserName] = (hc: HCursor) => {
        val nameDecoder = hc.downField("name").as[String]
            .flatMap(s => refineV[NonEmpty](s).leftMap(m => DecodingFailure(m, List())))
        val ageDecoder = hc.downField("age").as[Int]
            .flatMap(i => refineV[Positive](i).leftMap(m => DecodingFailure(m, List())))
        for {
            n <- nameDecoder
            age <- ageDecoder
        } yield UserName(n, age)
    }
}

case object SimpleUserName {
    implicit val simpleUserDecoder: Decoder[SimpleUserName] = (hc: HCursor) => {
        val nameDecoder = hc.downField("name").as[String]
        val ageDecoder = hc.downField("age").as[Int]
        for {
            n <- nameDecoder
            age <- ageDecoder
        } yield SimpleUserName(n, age)
    }
}

object Scratch extends App {

    val mat = UserName("mat", 24)
    // val badmat = UserName("", 24)
    // val badmatage = UserName("mat", -4)

    val goodJson: String = """
    {
    "name": "mat", 
    "age": 7
    }
    """

    val badJson: String = """
    {
    "name": "",
    "age": 7
    }
    """

    val badAgeJson: String = """
    {
    "name": "mat",
    "age": -4
    }
    """

    println(jawn.decode[UserName](goodJson))
    println(jawn.decode[SimpleUserName](goodJson))
    println(decode[UserName](badJson))
    println(decode[SimpleUserName](badJson))
}