Marshalling & Unmarshalling json with akka-http and json4s

build.sbt

name := "json-api-serializer"

version := "0.1"

scalaVersion := "2.13.6"

idePackagePrefix := Some("that.is.a.test")

libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor-typed" % "2.6.8",
  "com.typesafe.akka" %% "akka-stream" % "2.6.8",
  "com.typesafe.akka" %% "akka-http" % "10.2.4",
  "org.json4s" % "json4s-jackson_2.13" % "4.0.1",
  "de.heikoseeberger" % "akka-http-json4s_2.13" % "1.37.0"
)

src-main-scala-apiproject-Main.scala

package that.is.a.test
package apiproject

import akka.actor.typed.scaladsl.Behaviors
import akka.actor.typed.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import de.heikoseeberger.akkahttpjson4s.Json4sSupport
import org.json4s.{DefaultFormats, Formats, jackson}
import org.json4s.JsonAST.JValue
import org.json4s.jackson.Serialization

import scala.collection.mutable
import scala.concurrent.ExecutionContextExecutor

object Main extends App with Json4sSupport {

  implicit val system: ActorSystem[Nothing] = ActorSystem(Behaviors.empty, "my-system")
  implicit val executionContext: ExecutionContextExecutor = system.executionContext

  implicit val formats: Formats = DefaultFormats
  implicit val serialization: Serialization.type = jackson.Serialization

  val queue = new mutable.Queue[JValue]()

  val route =
    path("home") {
      get {
        complete {
          queue.toList
        }
      } ~
      post {
        entity(as[JValue]) { json: JValue =>
          complete {
            queue.enqueue(json)
            json
          }
        }
      } ~
      delete {
        entity(as[JValue]) { json: JValue =>
          complete {
            queue.dequeueFirst(_ == json)
            json
          }
        }
      }
    }

  Http().newServerAt("localhost", 8080).bind(route)
}