Controller to handle a custom request on Play Framework

CustomController.scala

package controllers

import play.api.mvc.{ActionBuilder, AnyContent, BaseController, BodyParser, Request, Result}

import scala.concurrent.{ExecutionContext, Future}

case class CustomRequest[A](underlying: Request[A]) {
  def body: A = underlying.body
}

class CustomActionBuilder[B](val parser: BodyParser[B])(
  implicit protected val executionContext: ExecutionContext,
) extends ActionBuilder[CustomRequest, B] {

  override def invokeBlock[A](
    request: Request[A],
    block: CustomRequest[A] => Future[Result]): Future[Result] = {

    // any pre-process here
    block(CustomRequest(request))
  }
}

trait CustomController {
  self: BaseController =>

  private lazy val customActionBuilder = {
    val parser = controllerComponents.parsers.defaultBodyParser
    val context = controllerComponents.executionContext
    new CustomActionBuilder[AnyContent](parser)(context)
  }

  def CustomAction: ActionBuilder[CustomRequest, AnyContent] = customActionBuilder
}