SignalR Skill

ASP.NET Core SignalR implementation for real-time client-server communication. Sorcha uses two hubs: ActionsHub (Blueprint Service) for workflow notifications and RegisterHub (Register Service) for ledger events. Both use group-based broadcasting with JWT authentication via query parameters.

Quick Start

Hub Implementation

// Strongly-typed hub with client interface
public class RegisterHub : Hub<IRegisterHubClient>
{
    public async Task SubscribeToRegister(string registerId)
    {
        await Groups.AddToGroupAsync(Context.ConnectionId, $"register:{registerId}");
    }
}

public interface IRegisterHubClient
{
    Task RegisterCreated(string registerId, string name);
    Task TransactionConfirmed(string registerId, string transactionId);
}

Sending from Services

public class NotificationService
{
    private readonly IHubContext<ActionsHub> _hubContext;

    public async Task NotifyActionConfirmedAsync(ActionNotification notification, CancellationToken ct)
    {
        await _hubContext.Clients
            .Group($"wallet:{notification.WalletAddress}")
            .SendAsync("ActionConfirmed", notification, ct);
    }
}

Client Connection (Testing)

var connection = new HubConnectionBuilder()
    .WithUrl($"{baseUrl}/actionshub?access_token={jwt}")
    .Build();

connection.On<ActionNotification>("ActionConfirmed", notification => { /* handle */ });
await connection.StartAsync();
await connection.InvokeAsync("SubscribeToWallet", walletAddress);

Key Concepts

Concept	Usage	Example
Groups	Route messages to subscribers	wallet:{address}, register:{id}, tenant:{id}
Typed Hubs	Compile-time safety	Hub<IRegisterHubClient>
IHubContext	Send from services	Inject IHubContext<THub>
JWT Auth	Query parameter auth	?access_token={jwt}

Common Patterns

Service Abstraction Over Hub

When: Decoupling business logic from SignalR implementation

// Interface in Services/Interfaces/
public interface INotificationService
{
    Task NotifyActionAvailableAsync(ActionNotification notification, CancellationToken ct = default);
}

// Register in DI
builder.Services.AddScoped<INotificationService, NotificationService>();

Hub Registration in Program.cs

builder.Services.AddSignalR();

// Map after authentication middleware
app.MapHub<ActionsHub>("/actionshub");
app.MapHub<RegisterHub>("/hubs/register");

See Also

• patterns - Hub patterns, group routing, typed clients
• workflows - Testing, scaling, authentication setup

Related Skills

• aspire - Service orchestration and configuration
• jwt - Authentication token setup for hub connections
• redis - Backplane configuration for scaling
• xunit - Integration testing patterns
• fluent-assertions - Test assertions for hub tests

Documentation Resources

Fetch latest SignalR documentation with Context7.

How to use Context7:

1. Use mcp__context7__resolve-library-id to search for "signalr aspnetcore"
2. Prefer website documentation (IDs starting with /websites/) over source code
3. Query with mcp__context7__query-docs using the resolved library ID

Library ID: /websites/learn_microsoft_en-us_aspnet_core (ASP.NET Core docs including SignalR)

Recommended Queries:

• "SignalR hub groups authentication"
• "SignalR Redis backplane scaling"
• "SignalR strongly typed hubs"