SignalR.Backplane.EFCore 1.1.0

SignalR.Backplane.EFCore

An EF Core–backed backplane for ASP.NET Core SignalR.
Enables horizontal scale-out across multiple application instances with:

• Ack-based delivery
• Subscriber heartbeat tracking
• Configurable cleanup policies

🚀 Installation

dotnet add package SignalR.Backplane.EFCore

⚡ Quick Start

1. Register services in Program.cs

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSignalR()
    .AddBackplaneDbContext<EfBackplaneDbContext>(
        options => options.UseSqlite(builder.Configuration.GetConnectionString("Main")),
        configure =>
        {
            configure.StoreSubscriberId = $"{Environment.MachineName}-{Guid.NewGuid()}";
            configure.AutoCreate = true;
        });

builder.Services.AddOpenApi();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
}

app.UseHttpsRedirection();

app.MapHub<NotificationHub>("/hubs/notification");

app.MapGet("/randomMessage", async (IHubContext<NotificationHub> hubContext) =>
{
    var msg = $"Random-{Guid.NewGuid():N}";
    await hubContext.Clients.All.SendAsync("signalr", msg);
    return Results.Ok(new { Sent = msg });
});

app.Run();

👉 Run multiple instances of your app pointing at the same database to scale SignalR out across nodes.
Each instance must use a unique SubscriberId.

🧭 Scale-Out Notes

• Use any EF Core provider as the shared store (Postgres, SQL Server, SQLite for dev/test).
• Ensure each app instance sets a unique StoreSubscriberId (e.g., hostname + GUID).
• If two stores use the same StoreSubscriberId, they are treated as instances of the same subscriber — acknowledgements from one apply to all (idempotent).
• AutoCreate = true simplifies the first run, but in production run migrations explicitly.
• Works seamlessly in containers, Kubernetes, Azure App Service, or VMs — no Redis required.

▶️ Running two instances locally (Kestrel)

Both servers share the same SQLite file for testing:

# Terminal 1
dotnet run --urls "https://localhost:5001"

# Terminal 2
dotnet run --urls "https://localhost:5002"

For production, use Postgres or SQL Server as the shared store.

▶️ Connect a .NET client

using Microsoft.AspNetCore.SignalR.Client;

var connection = new HubConnectionBuilder()
    .WithUrl("https://localhost:5002/hubs/notification") // match your server URL
    .WithAutomaticReconnect()
    .Build();

connection.On<string>("signalr", msg =>
{
    Console.WriteLine($"[NotificationHub] Received: {msg}");
});

await connection.StartAsync();
Console.WriteLine($"State: {connection.State}"); // should be Connected

Console.WriteLine("Connected to SignalR NotificationHub.");
Console.ReadKey();

await connection.DisposeAsync();

✅ You’ll see the message arrive regardless of which instance you send it to.

✨ Features

• Horizontal scalability — run multiple SignalR instances against a shared DB
• EF Core backplane — supports Postgres, SQL Server, and SQLite
• Ack-based message delivery — ensures subscribers confirm receipt
• Subscriber heartbeat tracking
• Configurable cleanup — TTL, logical delete, or physical delete
• Multiple hub support — via generic BusHubLifetimeManager<THub>

📖 Links

• NuGet Package
• GitHub Repository

📜 License

MIT License © Bill Nice G. Havugukuri