Connecting Clients

Registration

builder.Services.AddBluetoothLE();
builder.Services.AddBleHubClient<IGameHub>(ServiceUuid, GameHubCharacteristicUuid);

This registers the generated proxy (GameHubClient for IGameHub) as a singleton. Inject whichever shape you prefer:

Inject	You get
IBleHubClient<IGameHub>	Connection management, plus .Hub for calls and events (easiest to mock)
GameHubClient	The concrete generated proxy
IGameHub	Calls and events only

Discover & Connect

public partial class JoinViewModel(IBleHubClient<IGameHub> client) : ObservableObject
{
    IDisposable? scan;
    public ObservableCollection<BleHubHostInfo> Hosts { get; } = new();

    public void OnAppearing() => this.scan = client
        .Discover()   // scans for the hub's service UUID - dispose to stop
        .Subscribe(host => MainThread.BeginInvokeOnMainThread(() =>
        {
            if (!this.Hosts.Any(x => x.Id == host.Id))
                this.Hosts.Add(host);    // host.Name (advertised), host.Rssi
        }));

    [RelayCommand]
    async Task Join(BleHubHostInfo host)
    {
        this.scan?.Dispose();
        await client.Connect(host, new BleHubConnectOptions(
            Name: "Allan",
            AppVersion: AppInfo.Current.VersionString,
            Properties: new() { ["team"] = "blue" }
        ));
        var result = await client.Hub.Join("Allan", null);
    }
}

Connect does the following:

1. Connects to the host.
2. Requests the largest MTU the platforms allow.
3. Subscribes for pushes.
4. Completes the handshake.

The host may refuse the client: it is full, ValidateClient said no, or the hub isn’t running. In that case Connect throws a BleHubException with the reason.

Member
Status	Disconnected, Connecting, Connected, Disconnecting
StatusChanged / Connected / Disconnected	Disconnected carries the reason (host stopped, kicked, connection lost, you called Disconnect)
Host / HostName	The connected host, and the name it gave in the handshake
CanTransferFiles	See File Transfers
Disconnect()	Leaves the hub

Calls

var result = await client.Hub.MakeMove(4);
await client.Hub.Rematch();

using var cts = new CancellationTokenSource();
await foreach (var n in client.Hub.Countdown(10, cts.Token))
{
    if (n == 3)
        break;   // cancels the hub method on the host
}

• Concurrent calls are fine. Each is matched to its own reply.
• Timeouts: a call that gets no reply within BleHubProtocolOptions.RequestTimeout (30s by default) throws a TimeoutException. Streams aren’t timed out.
• Cancellation: cancelling a call’s CancellationToken stops waiting and cancels the hub method on the host.

builder.Services.ConfigureBleHubProtocol(o => o.RequestTimeout = TimeSpan.FromSeconds(10));

Events (pushes)

client.Hub.StateChanged += state => MainThread.BeginInvokeOnMainThread(() => this.Apply(state));
client.Hub.Emote += (from, emoji) => MainThread.BeginInvokeOnMainThread(() => this.Show($"{from} {emoji}"));

Events are raised on a background thread, one at a time and in the order the host sent them. Marshal to the UI thread yourself.

Failures

Exception	When
BleHubRemoteException	The hub method threw. Includes RemoteErrorType and Message
BleHubDisconnectedException	You called while not connected, or the connection dropped while a call was in flight (Reason says why)
TimeoutException	No reply within RequestTimeout
OperationCanceledException	You cancelled the call

Several Hubs on One Host

Register a client per hub contract. Connecting each to the same host shares one BLE connection, which is reference counted, so disconnecting one hub client leaves the others connected.

builder.Services.AddBleHubClient<IGameHub>(ServiceUuid, GameHubCharacteristicUuid);
builder.Services.AddBleHubClient<IChatHub>(ServiceUuid, ChatHubCharacteristicUuid);