Refactored checkFresh

app/controllers/HomeController.scala

@@ -4,7 +4,7 @@ import javax.inject.*
 import play.api.*
 import play.api.mvc.*
 import authentication.{AuthenticatedAction, AuthenticatedRequest}
-import caching.{Etagable, checkFresh}
+import caching.{Etagable, CheckFresh}
 import models.User
 import play.api.libs.json.Json
 
@@ -20,7 +20,7 @@ import java.util.Base64
 @Singleton
 class HomeController @Inject()(val controllerComponents: ControllerComponents,
                                authenticatedAction: AuthenticatedAction)
-  extends BaseController with Logging {
+  extends BaseController with Logging with CheckFresh {
 
   /**
    * Create an Action to render an HTML page.
@@ -35,7 +35,7 @@ class HomeController @Inject()(val controllerComponents: ControllerComponents,
 
   def userData = authenticatedAction { implicit request: AuthenticatedRequest[AnyContent] =>
     val user = request.user
-    request.checkFresh(user) {
+    checkFresh(user) {
       // TODO: put the max-age somewhere into config
       Ok(Json.toJson(user)).withHeaders("Etag" -> user.etag, "Cache-Control" -> "private, max-age=15, must-revalidate")
     }

app/controllers/caching/caching.scala

@@ -9,18 +9,18 @@ trait Etagable[A]:
   extension (a: A) def etag: String
 
 
-extension [A, R[X] <: Request[X], E: Etagable](request: R[A]) {
-  def checkFreshAsync(entity: E)(onStale: => Future[Result])(using ec: ExecutionContext): Future[Result] = {
-    compareEtag(entity).fold(onStale)(
+trait CheckFresh {
+  protected def checkFreshAsync[A, E: Etagable](entity: E)(onStale: => Future[Result])(using request: Request[A], ec: ExecutionContext): Future[Result] = {
+    compareEtag(request, entity).fold(onStale)(
       etag => Future.successful(NotModified.withHeaders("ETag" -> etag))
     )
   }
 
-  def checkFresh(entity: E)(onStale: => Result): Result = {
-    compareEtag(entity).fold(onStale)(
+  protected def checkFresh[A, E: Etagable](entity: E)(onStale: => Result)(using request: Request[A]): Result = {
+    compareEtag(request, entity).fold(onStale)(
       etag => NotModified.withHeaders("ETag" -> etag)
     )
   }
 
-  private def compareEtag(entity: E) = request.headers.get("If-None-Match").filter(e => e == entity.etag)
+  private def compareEtag[A, E: Etagable](request: Request[A], entity: E) = request.headers.get("If-None-Match").filter(e => e == entity.etag)
 }