Connecting Clients

Registration

builder.Services.AddUniversalHubClient<IGameHub>(
    GameCharacteristicUuid,
    "_mygame._tcp",                     // the hub's mDNS service type - the same as the host's AddHub
    o => o.ServiceUuid = ServiceUuid);  // the host's BLE service, if it set one

Resolve IUniversalHubClient<IGameHub>. It is an IBleHubClient<IGameHub>, so the generated proxy (client.Hub), events, Status, Disconnected, Rename and file methods are all there, and they work the same on either transport. IBleHubClient<IGameHub> and IGameHub resolve to the same connection.

Option	Default
ServiceUuid	BluetoothLE Hubs’ default	The host’s BLE service. Must match the host’s ServiceUuid
ServiceType	set from the registration	The mDNS service type to browse. Must match the hub’s
HttpConnectTimeout	6 seconds	How long one Wi-Fi address gets to answer before the next address (or BLE) is tried
AutomaticReconnect	true	Resume the Wi-Fi line after a short drop instead of disconnecting
HttpMessageHandlerFactory	null	The HTTP stack for Wi-Fi connections. Tests swap in an in-memory handler

Discovery

DiscoverAll() watches for hosts over BLE and mDNS at once. A host seen both ways is one HubHostInfo, raised again whenever either side changes. Dispose the subscription to stop.

public class JoinViewModel(IUniversalHubClient<IGameHub> client)
{
    IDisposable Scan() => client
        .DiscoverAll()
        .Subscribe(host =>
        {
            // host.Key: stable across both transports
            // host.Name, host.HostId, host.Rssi (when seen over BLE)
            // host.Transports: Ble, Http or both - None means it has gone
        });
}

• Merging. BLE results and mDNS results are merged by the host’s name, because Apple hosts can’t put a host id in a BLE advertisement. Give hosts distinct names (BleHubHostOptions.LocalName).
• Filtering. mDNS hosts are only listed when they’re running your hub and speak the same protocol version.
• Missing transports. A transport that can’t scan (Bluetooth off, no Wi-Fi) is skipped, and the other keeps going. Pass DiscoverAll(HubTransports.Http) to browse only one way.
• BLE only. Discover() and Connect(BleHubHostInfo) still give plain BluetoothLE Hubs behavior.

Connecting

await client.Connect(host, new HubConnectOptions("Allan") { Prefer = HubTransports.Http });

// client.Transport is Http or Ble (None while disconnected)
await client.Hub.MakeMove(4);

HubConnectOptions carries what the client tells the host about itself (Name, AppVersion, Properties) and which transports it may use:

• Prefer (Wi-Fi by default) is tried first when the host is reachable both ways. The other transport is the fallback.
• Allowed limits which transports may be used at all.
• Refusals aren’t retried. A host that refuses the client (full, ValidateClient, hub not running) is not tried again on the other transport.
• No migration. The transport is chosen at connect. A connection doesn’t move between Wi-Fi and BLE mid-session.

Resume

A short Wi-Fi drop is resumed. The line keeps its id and groups, and missed pushes are replayed. The hub sees no disconnect, and neither does the client. Turn this off with UniversalHubClientOptions.AutomaticReconnect = false.

A drop that outlasts the resume window ends in Disconnected with ClientTimeout. See disconnect reasons.

Connecting by Address

A host you have the address of, rather than one you discovered (a tunnel’s public URL, a typed address, a QR code), is reached over HTTP only:

await client.Connect(HubHostInfo.FromUrl(new Uri("https://abc.a.pinggy.link")));
await client.Connect(HubHostInfo.FromUrl(new Uri("http://192.168.1.20:5000"), endpoint: "/hubs"));

endpoint is the host’s AddUniversalServer endpoint, /hubs unless it was changed.

Files

UploadFile, UploadStream and DownloadFile work on either transport: L2CAP over BLE, plain HTTP over Wi-Fi. CanTransferFiles says whether the host has file transfers turned on.

var result = await client.UploadFile(avatarPath, "avatar-allan.jpg", progress);

See BluetoothLE Hubs file transfers for the host’s file settings, which both transports share.