Merge pull request #14389 from peppy/fix-messagepack-union

Fix android not being able to connect to multiplayer server

osu.Game.Tests/Online/TestMultiplayerMessagePackSerialization.cs

@@ -0,0 +1,72 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using MessagePack;
+using NUnit.Framework;
+using osu.Game.Online;
+using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Multiplayer.MatchTypes.TeamVersus;
+
+namespace osu.Game.Tests.Online
+{
+    [TestFixture]
+    public class TestMultiplayerMessagePackSerialization
+    {
+        [Test]
+        public void TestSerialiseRoom()
+        {
+            var room = new MultiplayerRoom(1)
+            {
+                MatchState = new TeamVersusRoomState()
+            };
+
+            var serialized = MessagePackSerializer.Serialize(room);
+
+            var deserialized = MessagePackSerializer.Deserialize<MultiplayerRoom>(serialized);
+
+            Assert.IsTrue(deserialized.MatchState is TeamVersusRoomState);
+        }
+
+        [Test]
+        public void TestSerialiseUserStateExpected()
+        {
+            var state = new TeamVersusUserState();
+
+            var serialized = MessagePackSerializer.Serialize(typeof(MatchUserState), state);
+            var deserialized = MessagePackSerializer.Deserialize<MatchUserState>(serialized);
+
+            Assert.IsTrue(deserialized is TeamVersusUserState);
+        }
+
+        [Test]
+        public void TestSerialiseUnionFailsWithSingalR()
+        {
+            var state = new TeamVersusUserState();
+
+            // SignalR serialises using the actual type, rather than a base specification.
+            var serialized = MessagePackSerializer.Serialize(typeof(TeamVersusUserState), state);
+
+            // works with explicit type specified.
+            MessagePackSerializer.Deserialize<TeamVersusUserState>(serialized);
+
+            // fails with base (union) type.
+            Assert.Throws<MessagePackSerializationException>(() => MessagePackSerializer.Deserialize<MatchUserState>(serialized));
+        }
+
+        [Test]
+        public void TestSerialiseUnionSucceedsWithWorkaround()
+        {
+            var state = new TeamVersusUserState();
+
+            // SignalR serialises using the actual type, rather than a base specification.
+            var serialized = MessagePackSerializer.Serialize(typeof(TeamVersusUserState), state, SignalRUnionWorkaroundResolver.OPTIONS);
+
+            // works with explicit type specified.
+            MessagePackSerializer.Deserialize<TeamVersusUserState>(serialized);
+
+            // works with custom resolver.
+            var deserialized = MessagePackSerializer.Deserialize<MatchUserState>(serialized, SignalRUnionWorkaroundResolver.OPTIONS);
+            Assert.IsTrue(deserialized is TeamVersusUserState);
+        }
+    }
+}

osu.Game/Online/HubClientConnector.cs

@@ -148,7 +148,12 @@ namespace osu.Game.Online
                 });
 
             if (RuntimeInfo.SupportsJIT && preferMessagePack)
-                builder.AddMessagePackProtocol();
+            {
+                builder.AddMessagePackProtocol(options =>
+                {
+                    options.SerializerOptions = SignalRUnionWorkaroundResolver.OPTIONS;
+                });
+            }
             else
             {
                 // eventually we will precompile resolvers for messagepack, but this isn't working currently

osu.Game/Online/Multiplayer/MatchRoomState.cs

@@ -15,9 +15,9 @@ namespace osu.Game.Online.Multiplayer
     /// </summary>
     [Serializable]
     [MessagePackObject]
-    [Union(0, typeof(TeamVersusRoomState))]
+    [Union(0, typeof(TeamVersusRoomState))] // IMPORTANT: Add rules to SignalRUnionWorkaroundResolver for new derived types.
-    // TODO: this will need to be abstract or interface when/if we get messagepack working. for now it isn't as it breaks json serialisation.
+    // TODO: abstract breaks json serialisation. attention will be required for iOS support (unless we get messagepack AOT working instead).
-    public class MatchRoomState
+    public abstract class MatchRoomState
     {
     }
 }

osu.Game/Online/Multiplayer/MatchUserRequest.cs

@@ -3,6 +3,7 @@
 
 using System;
 using MessagePack;
+using osu.Game.Online.Multiplayer.MatchTypes.TeamVersus;
 
 namespace osu.Game.Online.Multiplayer
 {
@@ -11,6 +12,7 @@ namespace osu.Game.Online.Multiplayer
     /// </summary>
     [Serializable]
     [MessagePackObject]
+    [Union(0, typeof(ChangeTeamRequest))] // IMPORTANT: Add rules to SignalRUnionWorkaroundResolver for new derived types.
     public abstract class MatchUserRequest
     {
     }

osu.Game/Online/Multiplayer/MatchUserState.cs

@@ -15,9 +15,9 @@ namespace osu.Game.Online.Multiplayer
     /// </summary>
     [Serializable]
     [MessagePackObject]
-    [Union(0, typeof(TeamVersusUserState))]
+    [Union(0, typeof(TeamVersusUserState))] // IMPORTANT: Add rules to SignalRUnionWorkaroundResolver for new derived types.
-    // TODO: this will need to be abstract or interface when/if we get messagepack working. for now it isn't as it breaks json serialisation.
+    // TODO: abstract breaks json serialisation. attention will be required for iOS support (unless we get messagepack AOT working instead).
-    public class MatchUserState
+    public abstract class MatchUserState
     {
     }
 }

osu.Game/Online/Multiplayer/OnlineMultiplayerClient.cs

@@ -39,7 +39,7 @@ namespace osu.Game.Online.Multiplayer
         {
             // Importantly, we are intentionally not using MessagePack here to correctly support derived class serialization.
             // More information on the limitations / reasoning can be found in osu-server-spectator's initialisation code.
-            connector = api.GetHubConnector(nameof(OnlineMultiplayerClient), endpoint, false);
+            connector = api.GetHubConnector(nameof(OnlineMultiplayerClient), endpoint);
 
             if (connector != null)
             {

osu.Game/Online/SignalRUnionWorkaroundResolver.cs

@@ -0,0 +1,61 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using MessagePack;
+using MessagePack.Formatters;
+using MessagePack.Resolvers;
+using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Multiplayer.MatchTypes.TeamVersus;
+
+namespace osu.Game.Online
+{
+    /// <summary>
+    /// Handles SignalR being unable to comprehend [Union] types correctly by redirecting to a known base (union) type.
+    /// See https://github.com/dotnet/aspnetcore/issues/7298.
+    /// </summary>
+    public class SignalRUnionWorkaroundResolver : IFormatterResolver
+    {
+        public static readonly MessagePackSerializerOptions OPTIONS =
+            MessagePackSerializerOptions.Standard.WithResolver(new SignalRUnionWorkaroundResolver());
+
+        private static readonly Dictionary<Type, IMessagePackFormatter> formatter_map = new Dictionary<Type, IMessagePackFormatter>
+        {
+            { typeof(TeamVersusUserState), new TypeRedirectingFormatter<TeamVersusUserState, MatchUserState>() },
+            { typeof(TeamVersusRoomState), new TypeRedirectingFormatter<TeamVersusRoomState, MatchRoomState>() },
+            { typeof(ChangeTeamRequest), new TypeRedirectingFormatter<ChangeTeamRequest, MatchUserRequest>() },
+
+            // These should not be required. The fallback should work. But something is weird with the way caching is done.
+            // For future adventurers, I would not advise looking into this further. It's likely not worth the effort.
+            { typeof(MatchUserState), new TypeRedirectingFormatter<MatchUserState, MatchUserState>() },
+            { typeof(MatchRoomState), new TypeRedirectingFormatter<MatchRoomState, MatchRoomState>() },
+            { typeof(MatchUserRequest), new TypeRedirectingFormatter<MatchUserRequest, MatchUserRequest>() },
+            { typeof(MatchServerEvent), new TypeRedirectingFormatter<MatchServerEvent, MatchServerEvent>() },
+        };
+
+        public IMessagePackFormatter<T> GetFormatter<T>()
+        {
+            if (formatter_map.TryGetValue(typeof(T), out var formatter))
+                return (IMessagePackFormatter<T>)formatter;
+
+            return StandardResolver.Instance.GetFormatter<T>();
+        }
+
+        public class TypeRedirectingFormatter<TActual, TBase> : IMessagePackFormatter<TActual>
+        {
+            private readonly IMessagePackFormatter<TBase> baseFormatter;
+
+            public TypeRedirectingFormatter()
+            {
+                baseFormatter = StandardResolver.Instance.GetFormatter<TBase>();
+            }
+
+            public void Serialize(ref MessagePackWriter writer, TActual value, MessagePackSerializerOptions options) =>
+                baseFormatter.Serialize(ref writer, (TBase)(object)value, StandardResolver.Options);
+
+            public TActual Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options) =>
+                (TActual)(object)baseFormatter.Deserialize(ref reader, StandardResolver.Options);
+        }
+    }
+}