Generic Codec[T] for Circle JSON parser

[aukgit]

Main Goal

Make circle JSON encode/decode on the abstract class level. Just like NewtonJson (https://www.newtonsoft.com/json)

I want to make a generic one where I have a [T] and that [T] transforms into something that can be convertible to JSON. Probably there is a boundary (I am unaware of).

Versions (Scala 2.13.1, Circle: 0.12.3)

lazy val scalaVersionF = "2.13.1"
lazy val circeVersion = "0.12.3"

  "io.circe" %% "circe-core" % circeVersion,
  "io.circe" %% "circe-generic" % circeVersion,
  "io.circe" %% "circe-parser" % circeVersion,
  "de.heikoseeberger" %% "akka-http-circe" % "1.31.0",

Issue Summary

Things work fine when the actual type is given, however, it doesn't work when generics are used.

AnyVal JSON Add

Reference: https://www.programcreek.com/scala/io.circe.Decoder

import io.circe.{Decoder, Encoder}
import shapeless.Unwrapped

trait AnyValCirceEncoding {
  implicit def anyValEncoder[V, U](implicit ev: V <:< AnyVal,
    V: Unwrapped.Aux[V, U],
    encoder: Encoder[U]): Encoder[V] = {
    val _ = ev
    encoder.contramap(V.unwrap)
  }

  implicit def anyValDecoder[V, U](implicit ev: V <:< AnyVal,
    V: Unwrapped.Aux[V, U],
    decoder: Decoder[U]): Decoder[V] = {
    val _ = ev
    decoder.map(V.wrap)
  }
}

object AnyValCirceEncoding extends AnyValCirceEncoding
trait CircleJsonSupport extends de.heikoseeberger.akkahttpcirce.FailFastCirceSupport
  with AnyValCirceEncoding

Examples

Abstract API Sample, CircleJsonSupport integrated

trait RestWebApiContracts[TTable, TRow, TKey]
  extends
    RestWebApi[TTable, TRow, TKey] with
    RestWebApiBodyProcessor[TTable, TRow, TKey] with
    RestWebApiMessages[TTable, TRow, TKey] with
    RestWebApiJson[TTable, TRow, TKey] with
    RestWebApiEntityJsonAdapter[TTable, TRow, TKey] with
    CircleJsonSupport // has the support for the Circle any value type

Build fails

abstract class AbstractRestWebApi[TTable, TRow, TKey]
(components : ControllerComponents)
  extends
    AbstractController(components) with
    RestWebApiContracts[TTable, TRow, TKey] {
  val service : AbstractBasicPersistentService[TTable, TRow, TKey]

  def getAll : Action[AnyContent] = Action { implicit request =>
      // cannot create for List[TRow]
      implicit val listEncoder: Encoder.AsObject[List[TRow]] = deriveEncoder[List[TRow]]
      val records : List[TRow] = service.getAll
      val json = records.asJson(listEncoder).space2
      Ok(json)
    }
}

Build Success and works fine if the same code is written in the actual class

class CampaignsApiController @Inject()(
  campaignService : CampaignService,
  components      : ControllerComponents)
  extends AbstractRestWebApi[Campaign, CampaignRow, Int](components) {
    override def getAll : Action[AnyContent] = Action { implicit request : Request[AnyContent] =>
      val campaigns: List[CampaignRow] = campaignService.getAll
      val json = campaigns.asJson.spaces2
      Ok(json) // works perfect and returns json array
    }
}

Build Success and works fine if casting happens properly

abstract class AbstractRestWebApi[TTable, TRow, TKey]
(components : ControllerComponents)
  extends
    AbstractController(components) with
    RestWebApiContracts[TTable, TRow, TKey] {
  val service : AbstractBasicPersistentService[TTable, TRow, TKey]

  def getAll : Action[AnyContent] = Action { implicit request =>
      // cannot create for List[TRow]
      implicitvallistEncoder:Encoder[List[CampaignRow]]=deriveEncoder[List[CampaignRow]]
      val campaigns=service.getAll
      val json =campaigns.asInstanceOf[List[CampaignRow]].asJson(listEncoder).spaces2
      Ok(json) // perfectly
    }
}

Implicts failed

Base Class

  lazy implicit val listEncoder : Encoder[List[TRow]] = Encoder[List[TRow]]
  lazy implicit val encoder : Encoder[TRow] = Encoder[TRow]
  lazy implicit val decoder : Decoder[TRow] = Decoder[TRow]
  lazy implicit val listDecoder : Decoder[List[TRow]] = Decoder[List[TRow]]

Concreate class Class

  override implicit val listEncoder : Encoder[List[CampaignRow]] = Encoder[List[CampaignRow]]
  override implicit val encoder : Encoder[CampaignRow] = Encoder[CampaignRow]
  override implicit val decoder : Decoder[CampaignRow] = Decoder[CampaignRow]
  override implicit val listDecoder : Decoder[List[CampaignRow]] = Decoder[List[CampaignRow]]

Also doesn't help

Case Class for CampaignRow (Slick Class)

case class CampaignRow(campaignid: Int, campaignname: String, contentcategoryid: String, totalbudgetcpm: Double = 0.0, spendalready: Double = 0.0, remainingamount: Double = 0.0, startdate: Option[Double] = Some(0.0), enddate: Option[Double] = Some(0.0), impressioncount: Int = 0, demandsideplatformid: Int, isrunning: Int = 0, priority: Int = 999, isretricttousergender: Int = 0, expectedusergender: Option[String], publisherid: Option[Int])

Build errors faced during

- could not find implicit value for parameter encoder: io.circe.Encoder[List[TRow]]
- could not find Lazy implicit value of type io.circe.generic.encoding.DerivedAsObjectEncoder[List[TRow]]
      implicit val listEncoder: Encoder.AsObject[List[TRow]] = deriveEncoder[List[TRow]]