PlayFramework 2.4 Scala ActionRefiner with parameter from url usage - scala

Question

I've made ActionRefiner to read language of current request from parameter in url:
class LangRequest[A](val lang: Lang, request: Request[A]) extends WrappedRequest[A](request)
def LangAction(lang: String) = new ActionRefiner[Request, LangRequest] {
def refine[A](input: Request[A]) = Future.successful {
val availLangs: List[String] = Play.current.configuration.getStringList("play.i18n.langs").get.toList
if (!availLangs.contains(lang))
Left {
input.acceptLanguages.head match {
case Lang(value, _) if availLangs.contains(value) => Redirect(controllers.routes.Application.index(value))
case _ => Redirect(controllers.routes.Application.index(availLangs.head))
}
}
else Right {
new LangRequest(Lang(lang), input)
}
}
}
and try to use it in action like this:
def login(lng: String) = LangAction(lng) { implicit request: Request[AnyContent] =>
Ok("Ok")
}
And I've got
"play.api.mvc.ActionRefiner[play.api.mvc.Request,controllers.actionbuilders.LangRequest]
does not take parameters"
error at compilation time. How can I use this ActionRefiner? In PlayFramework documentation https://www.playframework.com/documentation/2.4.x/ScalaActionsComposition they show ActionRefiner usages with Filter, Transformer like this:
(UserAction andThen ItemAction(itemId) andThen PermissionCheckAction)
and this does work. But how to use one ActionRefiner?

Answer 1

I'm sorry; this is pretty old, but I am facing a similar problem and wanted to post the solution so others could find it. I suspect it is because the first item in the chain of actions should be an ActionBuilder, in addition to whatever else. ActionTransformer is not a subtype of ActionBuilder, though it can be an argument to ActionBuilder#andThen.

Answer 2

It is correct, the ActionBuilder has to be the first element in the chain based on https://www.playframework.com/documentation/2.4.x/ScalaActionsComposition#Putting-it-all-together
On the other hand, there are scenarios where we need to pass arguments to the ActionRefiner due to interactions with the database (e.g. retrieve products using id). At this point, we need to #Inject dependencies like services to get access to DB and the function is a partial solution. So, we can wrap the function in class to inject the dependencies and also inherent from ActionBuilder due to we can have only one element in the chain and we need to start with an ActionBuilder.
class UserActionBuilder #Inject()(
val defaultBodyParsers: BodyParsers.Default,
userService: UserService
)(implicit val ec: ExecutionContext) {
def refine(userEmail: String): ActionRefiner[Request, UserRequest] with ActionBuilder[UserRequest, AnyContent] =
new ActionRefiner[Request, UserRequest] with ActionBuilder[UserRequest, AnyContent] {
def executionContext: ExecutionContext = ec
override def refine[A](request: Request[A]): Future[Either[Result, UserRequest[A]]] = {
userService.retrieveUserByEmail(userEmail)
.map {
case Some(user) if user.isActive => Right(UserRequest(user, request))
case _ => Left(Results.Forbidden("User is inactive"))
}
.recover { case ex: Throwable =>
Left(Results.InternalServerError(ex.getMessage))
}
}
override def parser: BodyParser[AnyContent] = defaultBodyParsers
}
}
case class UserRequest[A](user: User, request: Request[A])
extends WrappedRequest[A](request)
And then
class UserController #Inject()(
arguments...,
userAction: UserActionBuilder
)(implicit executionContext: ExecutionContext) {
def updateUserPurchase(emailUser: String): Action[UserPurchaseRequest] = {
userAction.refine(emailUser)).async(apiParser.parserOf[UserPurchaseRequest]) { implicit request =>
...
doUpdate(request.body, request.user)
...
}
}
}