Connection Setup

HARRRConnection wraps ASP.NET Core's HubConnection with typed RPC support. Create one using the static factory method.

Create a connection

Use the builder pattern to configure the underlying SignalR connection:

var connection = HARRRConnection.Create(builder =>
{
    builder.WithUrl("https://localhost:5001/apphub");
});

Or wrap an existing HubConnection:

var hubConnection = new HubConnectionBuilder()
    .WithUrl("https://localhost:5001/apphub")
    .Build();

var connection = HARRRConnection.Create(hubConnection);

Connection with authentication

Pass a token factory through SignalR's WithUrl options:

var connection = HARRRConnection.Create(builder =>
{
    builder.WithUrl("https://localhost:5001/apphub", options =>
    {
        options.AccessTokenProvider = () => Task.FromResult(GetCurrentToken());
    });
});

The token is sent with every SignalARRR request and automatically refreshed when the server challenges an expired token.

Auto-reconnect

var connection = HARRRConnection.Create(builder =>
{
    builder.WithUrl("https://localhost:5001/apphub");
    builder.WithAutomaticReconnect();
});

Start and stop

await connection.StartAsync();

// ... use the connection ...

await connection.StopAsync();
await connection.DisposeAsync();

Error handling

When a server method throws an exception, the client receives a structured error with the exception type and message:

try {
    var result = await chat.GetHistory();
} catch (HubException ex) {
    var error = HARRRError.Parse(ex);
    Console.WriteLine($"{error.Type}: {error.Message}");
    // "System.ArgumentException: Invalid value provided"
}

HARRRException extends HubException, so error details always reach the client — no EnableDetailedErrors configuration needed.

Connection events

connection.Closed += error =>
{
    Console.WriteLine($"Connection closed: {error?.Message}");
    return Task.CompletedTask;
};

connection.Reconnecting += error =>
{
    Console.WriteLine($"Reconnecting: {error?.Message}");
    return Task.CompletedTask;
};

connection.Reconnected += connectionId =>
{
    Console.WriteLine($"Reconnected as {connectionId}");
    return Task.CompletedTask;
};

Connection properties

Property	Type	Description
ConnectionId	string?	Current connection ID (null when disconnected)
State	HubConnectionState	Disconnected, Connecting, Connected, Reconnecting
ServerTimeout	TimeSpan	Server keepalive timeout
KeepAliveInterval	TimeSpan	Client keepalive ping interval
HandshakeTimeout	TimeSpan	Handshake timeout

Access the raw HubConnection

If you need SignalR features not exposed by HARRRConnection:

var hubConnection = connection.AsSignalRHubConnection();

Next steps

• Typed Methods — call server methods through interfaces
• Server-to-Client Handlers — handle server calls
• Streaming — stream data from the server