Auctions show

app/controllers/AuctionsController.scala

@@ -3,23 +3,25 @@ package controllers
 import actors.auctions.AuctionPublisher
 import controllers.authentication.AuthenticatedAction
 import dao.{AuctionsDAO, AuthTokensDAO}
-import models.AuctionStatus.Ready
-import models.{Auction, User}
 import org.apache.pekko.actor.typed.ActorRef
-import play.api.libs.functional.syntax.toFunctionalBuilderOps
 import play.api.libs.json.*
 import play.api.mvc.{BaseController, ControllerComponents}
 
 import javax.inject.{Inject, Singleton}
 import scala.concurrent.{ExecutionContext, Future}
+import models.Auction
+import caching.{CheckFresh, DigestEtagable, Etagable}
+
+import java.io.DataOutputStream
 
 @Singleton
 class AuctionsController @Inject()(val controllerComponents: ControllerComponents,
                                    val auctionsDAO: AuctionsDAO,
                                    val authTokensDAO: AuthTokensDAO,
                                    authenticatedAction: AuthenticatedAction,
-                                   val auctionPublisher: ActorRef[AuctionPublisher.Command],
+                                   val auctionPublisher: ActorRef[AuctionPublisher.Command])
-                                   implicit val ec: ExecutionContext) extends BaseController {
+                                  (implicit val ec: ExecutionContext)
+  extends BaseController with CheckFresh {
   def index = authenticatedAction.async { request =>
     for {
       auctions <- auctionsDAO.list_available(request.user)
@@ -27,6 +29,16 @@ class AuctionsController @Inject()(val controllerComponents: ControllerComponent
     } yield Ok(json)
   }
 
+  def show(id: Long) = authenticatedAction.async { implicit request =>
+    auctionsDAO.showAvailable(request.user, id).map { auctionOpt =>
+      auctionOpt.fold(NotFound) { auction =>
+        checkFresh(auction) {
+          Ok(Json.toJson(auction)).withHeaders("etag" -> auction.etag)
+        }
+      }
+    }
+  }
+
   def create = authenticatedAction.async(parse.json) { implicit request =>
     val auctionCreateDataResult = request.body.validate[AuctionCreateData]
     auctionCreateDataResult.fold(
@@ -44,4 +56,18 @@ class AuctionsController @Inject()(val controllerComponents: ControllerComponent
   private case class AuctionCreateData(name: String, startingPrice: BigDecimal)
 
   private given Reads[AuctionCreateData] = Json.reads[AuctionCreateData]
+
+  private given DigestEtagable[Auction] with {
+    override protected def writeDigestData(a: Auction, s: DataOutputStream): Unit = {
+      s.writeLong(a.id.getOrElse(0))
+      s.writeLong(a.authorId)
+      s.writeUTF(a.gid)
+      s.writeUTF(a.name)
+      s.writeLong(a.createdAt.getEpochSecond)
+
+      s.writeLong(a.currentBidderId.getOrElse(0))
+      a.currentBid.foreach(b => s.writeLong((b * 1000).toLong))
+      a.currentBidAt.foreach(ba => s.writeLong(ba.getEpochSecond))
+    }
+  }
 }

app/controllers/HomeController.scala

@@ -1,17 +1,15 @@
 package controllers
 
-import javax.inject.*
 import play.api.*
-import play.api.mvc.*
+import _root_.controllers.authentication.{AuthenticatedAction, AuthenticatedRequest}
-import authentication.{AuthenticatedAction, AuthenticatedRequest}
+import _root_.controllers.caching.{CheckFresh, DigestEtagable}
-import caching.{Etagable, CheckFresh}
 import models.User
 import play.api.libs.json.Json
+import play.api.mvc.*
 
-import java.nio.ByteBuffer
+import java.io.DataOutputStream
 import java.nio.charset.StandardCharsets.UTF_8
-import java.security.MessageDigest
+import javax.inject.*
-import java.util.Base64
 
 /**
  * This controller creates an `Action` to handle HTTP requests to the
@@ -37,21 +35,15 @@ class HomeController @Inject()(val controllerComponents: ControllerComponents,
     val user = request.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")
+      Ok(Json.toJson(user)).withHeaders("Cache-Control" -> "private, max-age=15, must-revalidate")
     }
   }
 
-  private given Etagable[models.User] with {
+  private given DigestEtagable[models.User] with {
-    private val base64 = Base64.getUrlEncoder
+    override protected def writeDigestData(a: User, s: DataOutputStream): Unit = {
-
+      s.writeLong(a.id.getOrElse(0))
-    extension (a: User)
+      s.write(a.gid.getBytes(UTF_8))
-      override def etag: String = {
+      s.write(a.username.getBytes(UTF_8))
-        val md = MessageDigest.getInstance("SHA-1")
+    }
-        md.update(ByteBuffer.allocate(8).putLong(a.id.getOrElse(0)))
-        md.update(a.gid.getBytes(UTF_8))
-        md.update(a.username.getBytes(UTF_8))
-
-        base64.encodeToString(md.digest())
-      }
   }
 }

app/controllers/caching/caching.scala

@@ -3,24 +3,55 @@ package controllers.caching
 import play.api.mvc.Results.NotModified
 import play.api.mvc.{Request, Result}
 
+import java.io.{ByteArrayOutputStream, DataOutputStream, OutputStream}
+import java.security.{DigestOutputStream, MessageDigest}
+import java.util.Base64
 import scala.concurrent.{ExecutionContext, Future}
+import scala.util.Using
 
 trait Etagable[A]:
   extension (a: A) def etag: String
 
 
+trait DigestEtagable[A] extends Etagable[A]:
+  private val base64 = Base64.getUrlEncoder.withoutPadding
+
+  protected def writeDigestData(a: A, s: DataOutputStream): Unit
+
+  extension (a: A) {
+    override def etag: String = {
+      val md = MessageDigest.getInstance("SHA-1")
+      Using(DataOutputStream(DigestOutputStream(OutputStream.nullOutputStream(), md))) { dos =>
+        writeDigestData(a, dos)
+        dos.flush()
+      }
+
+      base64.encodeToString(md.digest())
+    }
+  }
+
+
 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)(
+    compareEtag(request, entity).fold(
-      etag => Future.successful(NotModified.withHeaders("ETag" -> etag))
+      entityEtag => onStale.map(_.withHeaders("etag" -> entityEtag)),
+      requestEtag => Future.successful(notModified(requestEtag))
     )
   }
 
   protected def checkFresh[A, E: Etagable](entity: E)(onStale: => Result)(using request: Request[A]): Result = {
-    compareEtag(request, entity).fold(onStale)(
+    compareEtag(request, entity).fold(
-      etag => NotModified.withHeaders("ETag" -> etag)
+      entityEtag => onStale.withHeaders("etag" -> entityEtag),
+      requestEtag => notModified(requestEtag)
     )
   }
 
-  private def compareEtag[A, E: Etagable](request: Request[A], entity: E) = request.headers.get("If-None-Match").filter(e => e == entity.etag)
+  private def compareEtag[A, E: Etagable](request: Request[A], entity: E) = {
+    val entityEtag = entity.etag
+    request.headers.get("If-None-Match").filter(e => e == entityEtag) match {
+      case Some(etag) => Right(etag)
+      case None => Left(entityEtag)
+    }
+  }
+  private def notModified(etag: String) = NotModified.withHeaders("etag" -> etag)
 }

app/dao/AuctionsDAO.scala

@@ -1,31 +1,35 @@
 package dao
 
-import models.{Auction, AuctionStatus}
-import schemas.Auctions
-import schemas.given
 import play.api.db.slick.{DatabaseConfigProvider, HasDatabaseConfigProvider}
 import slick.jdbc.PostgresProfile
 import slick.jdbc.PostgresProfile.api.*
-
 import java.time.Instant
 import javax.inject.Inject
 import scala.concurrent.{ExecutionContext, Future}
 import scala.util.Random
 
+import models.{Auction, AuctionStatus, User}
+import schemas.Auctions
+import schemas.given
+
 class AuctionsDAO @Inject()(protected val dbConfigProvider: DatabaseConfigProvider)(implicit val ec: ExecutionContext)
   extends HasDatabaseConfigProvider[PostgresProfile] {
 
-  def list_available(user: models.User): Future[Seq[Auction]] = {
+  def list_available(user: User): Future[Seq[Auction]] = {
+    db.run(availableScope(user).result)
+  }
+
+  def showAvailable(user: User, id: Long): Future[Option[Auction]] = {
     db.run {
-      Auctions.filter(row => (row.status === AuctionStatus.Ready) && (row.authorId =!= user.id.get)).result
+      availableScope(user).filter(_.id === id).take(1).result.headOption
     }
   }
 
-  def list_created_by(user: models.User): Future[Seq[Auction]] = {
+  def list_created_by(user: User): Future[Seq[Auction]] = {
     db.run(Auctions.filter(_.authorId === user.id).result)
   }
 
-  def create(name: String, startingPrice: BigDecimal, author: models.User): Future[Auction] = {
+  def create(name: String, startingPrice: BigDecimal, author: User): Future[Auction] = {
     val auction = Auction(
       id = None, name = name,
       gid = Random.alphanumeric.take(24).mkString,
@@ -45,6 +49,10 @@ class AuctionsDAO @Inject()(protected val dbConfigProvider: DatabaseConfigProvid
 
   def changeStatus(auctionId: Long, status: AuctionStatus): Future[Boolean] = {
     db.run(Auctions.filter(_.id === auctionId).map(_.status).update(status))
-    .map(_ == 1)
+      .map(_ == 1)
+  }
+
+  private def availableScope(user: User) = {
+    Auctions.filter(row => (row.status === AuctionStatus.Ready) && (row.authorId =!= user.id.get))
   }
 }

conf/routes

@@ -15,6 +15,7 @@ GET /user_data                      controllers.HomeController.userData()
 GET     /assets/*file               controllers.Assets.versioned(path="/public", file: Asset)
 
 GET     /auctions                   controllers.AuctionsController.index()
+GET     /auctions/:id               controllers.AuctionsController.show(id: Long)
 POST    /auctions                   controllers.AuctionsController.create()
 
 -> /-devel                          controllers.devel.DevRouter