osu/osu.Game/Online/HubClientConnector.cs

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// 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.
#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.Bindables;
using osu.Framework.Logging;
using osu.Game.Online.API;
namespace osu.Game.Online
{
public class HubClientConnector : IHubClientConnector
{
/// <summary>
/// Invoked whenever a new hub connection is built, to configure it before it's started.
/// </summary>
public Action<HubConnection>? ConfigureConnection { get; set; }
private readonly string clientName;
private readonly string endpoint;
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private readonly string versionHash;
private readonly IAPIProvider api;
/// <summary>
/// The current connection opened by this connector.
/// </summary>
public HubConnection? CurrentConnection { get; private set; }
/// <summary>
/// Whether this is connected to the hub, use <see cref="CurrentConnection"/> to access the connection, if this is <c>true</c>.
/// </summary>
public IBindable<bool> IsConnected => isConnected;
private readonly Bindable<bool> isConnected = new Bindable<bool>();
private readonly SemaphoreSlim connectionLock = new SemaphoreSlim(1);
private CancellationTokenSource connectCancelSource = new CancellationTokenSource();
private readonly IBindable<APIState> apiState = new Bindable<APIState>();
/// <summary>
/// Constructs a new <see cref="HubClientConnector"/>.
/// </summary>
/// <param name="clientName">The name of the client this connector connects for, used for logging.</param>
/// <param name="endpoint">The endpoint to the hub.</param>
/// <param name="api"> An API provider used to react to connection state changes.</param>
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/// <param name="versionHash">The hash representing the current game version, used for verification purposes.</param>
public HubClientConnector(string clientName, string endpoint, IAPIProvider api, string versionHash)
{
this.clientName = clientName;
this.endpoint = endpoint;
this.api = api;
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this.versionHash = versionHash;
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;
}
}, true);
}
private async Task connect()
{
cancelExistingConnect();
if (!await connectionLock.WaitAsync(10000).ConfigureAwait(false))
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).ConfigureAwait(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($"{clientName} connecting...", LoggingTarget.Network);
try
{
// importantly, rebuild the connection each attempt to get an updated access token.
CurrentConnection = buildConnection(cancellationToken);
await CurrentConnection.StartAsync(cancellationToken).ConfigureAwait(false);
Logger.Log($"{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).ConfigureAwait(false);
}
}
}
finally
{
connectionLock.Release();
}
}
private HubConnection buildConnection(CancellationToken cancellationToken)
{
var builder = new HubConnectionBuilder()
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.WithUrl(endpoint, options =>
{
options.Headers.Add("Authorization", $"Bearer {api.AccessToken}");
options.Headers.Add("OsuVersionHash", versionHash);
});
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();
ConfigureConnection?.Invoke(newConnection);
newConnection.Closed += ex => onConnectionClosed(ex, cancellationToken);
return newConnection;
}
private Task onConnectionClosed(Exception? ex, CancellationToken cancellationToken)
{
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;
}
private async Task disconnect(bool takeLock)
{
cancelExistingConnect();
if (takeLock)
{
if (!await connectionLock.WaitAsync(10000).ConfigureAwait(false))
throw new TimeoutException("Could not obtain a lock to disconnect. A previous attempt is likely stuck.");
}
try
{
if (CurrentConnection != null)
await CurrentConnection.DisposeAsync().ConfigureAwait(false);
}
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")}";
public void Dispose()
{
apiState.UnbindAll();
cancelExistingConnect();
}
}
}