diff --git a/osu.Game/Online/HubClientConnector.cs b/osu.Game/Online/HubClientConnector.cs new file mode 100644 index 0000000000..49b1ab639a --- /dev/null +++ b/osu.Game/Online/HubClientConnector.cs @@ -0,0 +1,209 @@ +// Copyright (c) ppy Pty Ltd . Licensed under the MIT Licence. +// See the LICENCE file in the repository root for full licence text. + +#nullable enable + +using System; +using System.Threading; +using System.Threading.Tasks; +using Microsoft.AspNetCore.SignalR.Client; +using Microsoft.Extensions.DependencyInjection; +using Newtonsoft.Json; +using osu.Framework; +using osu.Framework.Allocation; +using osu.Framework.Bindables; +using osu.Framework.Graphics; +using osu.Framework.Logging; +using osu.Game.Online.API; + +namespace osu.Game.Online +{ + /// + /// A component that maintains over a hub connection between client and server. + /// + public class HubClientConnector : Component + { + /// + /// Invoked whenever a new hub connection is built. + /// + public Action? OnNewConnection; + + private readonly string clientName; + private readonly string endpoint; + + /// + /// The current connection opened by this connector. + /// + public HubConnection? CurrentConnection { get; private set; } + + /// + /// Whether this is connected to the hub, use to access the connection, if this is true. + /// + public IBindable IsConnected => isConnected; + + private readonly Bindable isConnected = new Bindable(); + private readonly SemaphoreSlim connectionLock = new SemaphoreSlim(1); + private CancellationTokenSource connectCancelSource = new CancellationTokenSource(); + + [Resolved] + private IAPIProvider api { get; set; } = null!; + + private readonly IBindable apiState = new Bindable(); + + /// + /// Constructs a new . + /// + /// The name of the client this connector connects for, used for logging. + /// The endpoint to the hub. + public HubClientConnector(string clientName, string endpoint) + { + this.clientName = clientName; + this.endpoint = endpoint; + } + + [BackgroundDependencyLoader] + private void load() + { + apiState.BindTo(api.State); + apiState.BindValueChanged(state => + { + switch (state.NewValue) + { + case APIState.Failing: + case APIState.Offline: + Task.Run(() => disconnect(true)); + break; + + case APIState.Online: + Task.Run(connect); + break; + } + }); + } + + private async Task connect() + { + cancelExistingConnect(); + + if (!await connectionLock.WaitAsync(10000)) + throw new TimeoutException("Could not obtain a lock to connect. A previous attempt is likely stuck."); + + try + { + while (apiState.Value == APIState.Online) + { + // ensure any previous connection was disposed. + // this will also create a new cancellation token source. + await disconnect(false); + + // this token will be valid for the scope of this connection. + // if cancelled, we can be sure that a disconnect or reconnect is handled elsewhere. + var cancellationToken = connectCancelSource.Token; + + cancellationToken.ThrowIfCancellationRequested(); + + Logger.Log($"{clientName} connecting...", LoggingTarget.Network); + + try + { + // importantly, rebuild the connection each attempt to get an updated access token. + CurrentConnection = createConnection(cancellationToken); + + await CurrentConnection.StartAsync(cancellationToken); + + Logger.Log($"{clientName} connected!", LoggingTarget.Network); + isConnected.Value = true; + return; + } + catch (OperationCanceledException) + { + //connection process was cancelled. + throw; + } + catch (Exception e) + { + Logger.Log($"{clientName} connection error: {e}", LoggingTarget.Network); + + // retry on any failure. + await Task.Delay(5000, cancellationToken); + } + } + } + finally + { + connectionLock.Release(); + } + } + + private HubConnection createConnection(CancellationToken cancellationToken) + { + var builder = new HubConnectionBuilder() + .WithUrl(endpoint, options => { options.Headers.Add("Authorization", $"Bearer {api.AccessToken}"); }); + + if (RuntimeInfo.SupportsJIT) + builder.AddMessagePackProtocol(); + else + { + // eventually we will precompile resolvers for messagepack, but this isn't working currently + // see https://github.com/neuecc/MessagePack-CSharp/issues/780#issuecomment-768794308. + builder.AddNewtonsoftJsonProtocol(options => { options.PayloadSerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore; }); + } + + var newConnection = builder.Build(); + + OnNewConnection?.Invoke(newConnection); + + newConnection.Closed += ex => + { + isConnected.Value = false; + + Logger.Log(ex != null ? $"{clientName} lost connection: {ex}" : $"{clientName} disconnected", LoggingTarget.Network); + + // make sure a disconnect wasn't triggered (and this is still the active connection). + if (!cancellationToken.IsCancellationRequested) + Task.Run(connect, default); + + return Task.CompletedTask; + }; + + return newConnection; + } + + private async Task disconnect(bool takeLock) + { + cancelExistingConnect(); + + if (takeLock) + { + if (!await connectionLock.WaitAsync(10000)) + throw new TimeoutException("Could not obtain a lock to disconnect. A previous attempt is likely stuck."); + } + + try + { + if (CurrentConnection != null) + await CurrentConnection.DisposeAsync(); + } + finally + { + CurrentConnection = null; + if (takeLock) + connectionLock.Release(); + } + } + + private void cancelExistingConnect() + { + connectCancelSource.Cancel(); + connectCancelSource = new CancellationTokenSource(); + } + + public override string ToString() => $"Connector for {clientName} ({(IsConnected.Value ? "connected" : "not connected")}"; + + protected override void Dispose(bool isDisposing) + { + base.Dispose(isDisposing); + cancelExistingConnect(); + } + } +}