Implement WebSocket server skeleton for external integrations

osu.Desktop/IPC/Messages/HitCountMessage.cs

@@ -0,0 +1,13 @@
+// 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 Newtonsoft.Json;
+
+namespace osu.Desktop.IPC.Messages
+{
+    public class HitCountMessage : OsuWebSocketMessage
+    {
+        [JsonProperty("new_hits")]
+        public long NewHits { get; init; }
+    }
+}

osu.Desktop/IPC/Messages/OsuWebSocketMessage.cs

@@ -0,0 +1,19 @@
+// 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 Newtonsoft.Json;
+using osu.Framework.Extensions.TypeExtensions;
+
+namespace osu.Desktop.IPC.Messages
+{
+    public abstract class OsuWebSocketMessage
+    {
+        [JsonProperty("type")]
+        public string Type { get; }
+
+        protected OsuWebSocketMessage()
+        {
+            Type = GetType().ReadableName();
+        }
+    }
+}

osu.Desktop/IPC/OsuWebSocketProvider.cs

@@ -0,0 +1,75 @@
+// 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.Linq;
+using System.Threading;
+using osu.Desktop.IPC.Messages;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Logging;
+using osu.Game.Configuration;
+using osu.Game.IPC;
+using osu.Game.Online.Multiplayer;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+using JsonConvert = Newtonsoft.Json.JsonConvert;
+
+namespace osu.Desktop.IPC
+{
+    public partial class OsuWebSocketProvider : Component
+    {
+        private WebSocketServer? server;
+        private readonly Bindable<ScoreInfo> lastLocalScore = new Bindable<ScoreInfo>();
+
+        [BackgroundDependencyLoader]
+        private void load(SessionStatics sessionStatics)
+        {
+            server = new WebSocketServer(49727);
+            server.StartAsync().FireAndForget(onError: ex => Logger.Error(ex, "Failed to start websocket"));
+
+            sessionStatics.BindWith(Static.LastLocalUserScore, lastLocalScore);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            lastLocalScore.BindValueChanged(val =>
+            {
+                if (val.NewValue == null)
+                    return;
+
+                if (server?.IsRunning != true)
+                    return;
+
+                var msg = new HitCountMessage { NewHits = val.NewValue.Statistics.Where(kv => kv.Key.IsBasic() && kv.Key.IsHit()).Sum(kv => kv.Value) };
+                broadcast(msg);
+            });
+        }
+
+        private void broadcast(OsuWebSocketMessage message)
+        {
+            if (server?.IsRunning != true)
+                return;
+
+            string messageString = JsonConvert.SerializeObject(message);
+            server.BroadcastAsync(messageString).FireAndForget();
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (server?.IsRunning == true)
+            {
+                var cts = new CancellationTokenSource();
+                cts.CancelAfter(TimeSpan.FromSeconds(10));
+                server.StopAsync(cts.Token).WaitSafely();
+                server = null;
+            }
+        }
+    }
+}

osu.Desktop/OsuGameDesktop.cs

@@ -6,6 +6,7 @@
 using System.Reflection;
 using System.Runtime.Versioning;
 using Microsoft.Win32;
+using osu.Desktop.IPC;
 using osu.Desktop.Performance;
 using osu.Desktop.Security;
 using osu.Framework.Platform;
@@ -35,6 +36,8 @@ internal partial class OsuGameDesktop : OsuGame
 
         public bool IsFirstRun { get; init; }
 
+        public bool EnableWebSocketServer { get; init; }
+
         public OsuGameDesktop(string[]? args = null)
             : base(args)
         {
@@ -148,6 +151,9 @@ protected override void LoadComplete()
 
             osuSchemeLinkIPCChannel = new OsuSchemeLinkIPCChannel(Host, this);
             archiveImportIPCChannel = new ArchiveImportIPCChannel(Host, this);
+
+            if (EnableWebSocketServer)
+                Add(new OsuWebSocketProvider());
         }
 
         public override void SetHost(GameHost host)

osu.Desktop/Program.cs

@@ -140,7 +140,8 @@ public static void Main(string[] args)
                 {
                     host.Run(new OsuGameDesktop(args)
                     {
-                        IsFirstRun = isFirstRun
+                        IsFirstRun = isFirstRun,
+                        EnableWebSocketServer = Environment.GetEnvironmentVariable("OSU_WEBSOCKET_SERVER") == "1",
                     });
                 }
             }

osu.Game.Tests/IPC/WebSocketClient.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.Net.WebSockets;
+using System.Threading;
+using System.Threading.Tasks;
+using osu.Game.IPC;
+
+namespace osu.Game.Tests.IPC
+{
+    public sealed class WebSocketClient : IDisposable
+    {
+        public event Action<string>? MessageReceived;
+        public event Action? Closed;
+
+        private readonly int port;
+        private WebSocketChannel? channel;
+
+        public WebSocketClient(int port)
+        {
+            this.port = port;
+        }
+
+        public async Task Start(CancellationToken cancellationToken = default)
+        {
+            var webSocket = new ClientWebSocket();
+            await webSocket.ConnectAsync(new Uri($@"ws://localhost:{port}/"), cancellationToken);
+            channel = new WebSocketChannel(webSocket);
+            channel.MessageReceived += (msg) => MessageReceived?.Invoke(msg);
+            channel.ClosedPrematurely += () => Closed?.Invoke();
+            channel.Start(cancellationToken);
+        }
+
+        public async Task SendAsync(string message)
+        {
+            if (channel == null)
+                throw new InvalidOperationException($@"Must {nameof(Start)} first.");
+
+            await channel.SendAsync(message);
+        }
+
+        public async Task StopAsync(CancellationToken stoppingToken = default)
+        {
+            try
+            {
+                if (channel != null)
+                    await channel.StopAsync(stoppingToken).ConfigureAwait(false);
+            }
+            catch (OperationCanceledException)
+            {
+                // has to be caught manually because outer task isn't accepting `stoppingToken`.
+            }
+        }
+
+        public void Dispose()
+        {
+            channel?.Dispose();
+        }
+    }
+}