VitalRouter is a high-performance, zero-allocation in-memory messaging library for C#. It is specifically designed for environments where performance and decoupling are critical, such as Unity games or complex .NET applications.

By using simple attributes, you can implement asynchronous handlers, middleware (interceptors), and advanced sequence control. VitalRouter leverages Roslyn Source Generators to produce highly efficient code, promoting a clean, unidirectional control flow with minimal overhead.

Visit vitalrouter.hadashikick.jp to see the full documentation.

• Zero Allocation: Optimized for high-frequency messaging without GC pressure.
• Thread-Safe: Designed for safe use across multiple threads.
• Unidirectional Flow: Promotes a predictable data flow through your application.
• Declarative Routing: Use attributes like [Routes] and [Route] to define handlers.
• Async Interceptor Pipeline: Build sophisticated message processing chains.
• Versatile Compatibility: Works seamlessly in both Unity and standard .NET projects.
• DI Integration: Native support for VContainer (Unity) and Microsoft.Extensions.DependencyInjection.

VitalRouter follows a simple messaging flow. A Publisher sends a Command to a Router, which then dispatches it through optional Interceptors to one or more Handlers.

---
config:
  theme: dark
---
graph LR
    Publisher[Publisher] -- PublishAsync --> Router[Router]
    subgraph Pipeline
        Router -- next --> Interceptor1[Interceptor A]
        Interceptor1 -- next --> Interceptor2[Interceptor B]
    end
    Interceptor2 -- Invoke --> Handler[Handler/Presenter]

Commands are lightweight data structures representing an event or action.

// record structs are recommended for zero-allocation messaging
public readonly record struct MoveCommand(Vector3 Destination) : ICommand;

Use the [Routes] attribute on a partial class to receive commands.

[Routes]
public partial class PlayerPresenter
{
    // Use ValueTask for pure .NET performance
    [Route]
    public void On(MoveCommand cmd)
    {
        Console.WriteLine($"Moving to {cmd.Destination}");
    }

    // Use UniTask for Unity-specific async handling
    [Route]
    public async UniTask On(SomeAsyncCommand cmd)
    {
        await DoSomethingAsync();
    }
}

Connect your handler to a router and start sending commands.

var router = new Router();
var presenter = new PlayerPresenter();

// MapTo returns a Subscription (IDisposable)
using var subscription = presenter.MapTo(router);

// Publish a message
await router.PublishAsync(new MoveCommand(new Vector3(1, 0, 0)));

You can also subscribe using lambdas without using the source generator.

// Simple subscription
router.Subscribe<MoveCommand>(cmd => { /* ... */ });

// Async subscription with ordering
router.SubscribeAwait<MoveCommand>(async (cmd, ct) => 
{
    await DoSomethingAsync();
}, CommandOrdering.Sequential);

// Inline interceptors (Filters)
router
    .WithFilter<MoveCommand>(async (cmd, context, next) =>
    {
        Console.WriteLine("Before");
        await next(cmd, context);
        Console.WriteLine("After");
    })
    .Subscribe(cmd => { /* ... */ });

VitalRouter is highly optimized for Unity, especially when combined with UniTask.

When using MapTo in a MonoBehaviour, always bind the subscription to the object's lifecycle.

[Routes]
public partial class CharacterController : MonoBehaviour
{
    private void Start()
    {
        // Bind the subscription to this GameObject's lifecycle
        this.MapTo(Router.Default).AddTo(destroyCancellationToken);
    }

    [Route]
    public void On(MoveCommand cmd)
    {
        transform.position = cmd.Destination;
    }
}

UniTask is a fast async/await extension for Unity. VitalRouter actively supports UniTask. Requirements: UniTask >= 2.5.5

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• Unity 2022.2+ (Uses Incremental Source Generator)
• .NET 6.0+

Package	Latest version
VitalRouter
VitalRouter.Extensions.DependencyInjection
VitalRouter.R3
VitalRouter.MRuby

1. Install NuGetForUnity.
2. Search and install VitalRouter packages in the NuGet window.

Optional (UPM)

If you prefer UPM, you can install the assembly for Unity via Git URL:

https://github.com/hadashiA/VitalRouter.git?path=/src/VitalRouter.Unity/Assets/VitalRouter#2.0.5

Pipelining of async interceptors for published messages is possible. This is a general strong pattern for data exchange.

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R3 is the next generation Reactive Extensions implementation in the C# world. VitalRouter supports the ability to work with R3.

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Control command publishing via external MRuby scripts. Fiber in mruby and async/await in C# are fully integrated.

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Based on large-scale production usage (e.g., HybridFrame):

1. Prefer record structs: For commands that are pure data, record struct provides equality comparison and zero-allocation benefits.
2. Explicit Lifecycles: Always use .AddTo(destroyCancellationToken) or manual Dispose() to avoid memory leaks and ghost event handling.
3. UniTask for Unity: Use UniTask or UniTaskVoid as return types in Unity handlers to leverage optimized pooling. Use ValueTask for pure .NET projects.
4. Contextual Metadata: Use PublishContext for cross-cutting concerns (logging IDs, cancellation tokens, user permissions) rather than polluting your command structs.
5. Sequential by Default for UI: Use CommandOrdering.Sequential for UI animations or dialogue sequences to prevent race conditions.
6. DI Integration: In Unity, VContainer (>= 1.16.6) is highly recommended for managing router lifecycles and handler registration.

MIT

@hadashiA