restore the favourite opponents page - with caching

Author: ornicar

app/controllers/User.scala

@@ -235,23 +235,16 @@ object User extends LilaController {
     }
   }
 
-  def opponents(username: String) = Open { implicit ctx =>
-    OptionFuOk(UserRepo named username) { user =>
-      lila.game.BestOpponents(user.id, 50) flatMap { ops =>
-        ctx.isAuth.fold(
-          Env.pref.api.followables(ops map (_._1.id)),
-          fuccess(List.fill(50)(true))
-        ) flatMap { followables =>
-            (ops zip followables).map {
-              case ((u, nb), followable) => ctx.userId ?? {
-                relationApi.fetchRelation(_, u.id)
-              } map { lila.relation.Related(u, nb.some, followable, _) }
-            }.sequenceFu map { relateds =>
-              html.user.opponents(user, relateds)
-            }
-          }
-      }
-    }
+  def opponents = Auth { implicit ctx => me =>
+    for {
+      ops <- Env.game.bestOpponents(me.id)
+      followables <- Env.pref.api.followables(ops map (_._1.id))
+      relateds <- ops.zip(followables).map {
+        case ((u, nb), followable) => relationApi.fetchRelation(me.id, u.id) map {
+          lila.relation.Related(u, nb.some, followable, _)
+        }
+      }.sequenceFu
+    } yield html.user.opponents(me, relateds)
   }
 
   def perfStat(username: String, perfKey: String) = Open { implicit ctx =>

app/views/base/layout.scala.html

@@ -185,7 +185,7 @@ <h1>
         <div class="content list"></div>
         <div class="nobody@if(ctx.onlineFriends.users.nonEmpty){ none}">
           <span>@trans.noFriendsOnline()</span>
-          <a class="find button" href="@routes.User.opponents(me.username)">
+          <a class="find button" href="@routes.User.opponents">
             <span class="is3 text" data-icon="h">@trans.findFriends()</span>
           </a>
         </div>

app/views/user/show.scala.html

@@ -200,8 +200,9 @@ <h1 class="lichess_title user_link @if(isOnline(u.id)){online}else{offline}">
         <a href="@routes.Account.profile" title="@trans.editProfile()">
           Profile completion: @profile.completionPercent%
         </a>
+        <br />
+        <a href="@routes.User.opponents">@trans.favoriteOpponents()</a>
         }
-        <!-- <a href="@routes.User.opponents(u.username)">@trans.favoriteOpponents()</a> -->
         <br />
         <br />
         <p>@trans.tpTimeSpentPlaying(showPeriod(info.playTime.totalPeriod))</p>

conf/routes

@@ -51,7 +51,6 @@ GET   /insights/:username/:metric/:dimension/*filters controllers.Insight.path(u
 GET   /@/:username/tournaments/:path   controllers.UserTournament.path(username: String, path: String, page: Int ?= 1)
 
 # User
-GET   /@/:username/opponents           controllers.User.opponents(username: String)
 GET   /@/:username/mod                 controllers.User.mod(username: String)
 POST  /@/:username/note                controllers.User.writeNote(username: String)
 GET   /@/:username/mini                controllers.User.showMini(username: String)
@@ -60,6 +59,7 @@ GET   /@/:username/perf/:perfKey       controllers.User.perfStat(username: Strin
 GET   /@/:username/:filterName         controllers.User.showFilter(username: String, filterName: String, page: Int ?= 1)
 GET   /@/:username                     controllers.User.show(username: String)
 GET   /player/myself                   controllers.User.myself
+GET   /player/opponents                controllers.User.opponents
 GET   /player                          controllers.User.list
 GET   /player/top/200/:perfKey         controllers.User.top200(perfKey: String)
 GET   /player/top/week                 controllers.User.topWeek

modules/game/src/main/BestOpponents.scala

@@ -1,11 +1,20 @@
 package lila.game
 
+import com.github.blemale.scaffeine.{ AsyncLoadingCache, Scaffeine }
+import scala.concurrent.duration._
+
 import lila.user.{ User, UserRepo }
 
-object BestOpponents {
+final class BestOpponents {
+
+  private val limit = 30
+
+  private val userIdsCache = Scaffeine()
+    .expireAfterWrite(15 minutes)
+    .buildAsyncFuture[User.ID, List[(User.ID, Int)]] { GameRepo.bestOpponents(_, limit) }
 
-  def apply(userId: String, limit: Int): Fu[List[(User, Int)]] =
-    GameRepo.bestOpponents(userId, limit) flatMap { opponents =>
+  def apply(userId: String): Fu[List[(User, Int)]] =
+    userIdsCache get userId flatMap { opponents =>
       UserRepo enabledByIds opponents.map(_._1) map {
         _ flatMap { user =>
           opponents find (_._1 == user.id) map { opponent =>

modules/game/src/main/Env.scala

@@ -84,6 +84,8 @@ final class Env(
   }
 
   lazy val stream = new GameStream(system)
+
+  lazy val bestOpponents = new BestOpponents
 }
 
 object Env {

modules/game/src/main/GameRepo.scala

@@ -362,7 +362,7 @@ object GameRepo {
 
   // #TODO expensive stuff, run on DB replica
   // Can't be done on reactivemongo 0.11.9 :(
-  def bestOpponents(userId: String, limit: Int): Fu[List[(String, Int)]] = {
+  private[game] def bestOpponents(userId: String, limit: Int): Fu[List[(User.ID, Int)]] = {
     import reactivemongo.api.collections.bson.BSONBatchCommands.AggregationFramework._
     coll.aggregate(Match($doc(F.playerUids -> userId)), List(
       Match($doc(F.playerUids -> $doc("$size" -> 2))),