DelegatR

DelegatR is a minimal, in-process mediator for .NET.

It provides a small set of contracts plus a single default runtime Mediator implementation that can dispatch requests and publish notifications. Resolution is DI-agnostic via a ServiceFactory delegate.

V1 scope

• Send:
  • Dispatch a request to exactly one handler
  • Optional pipeline behaviors that wrap the handler
  • Cancellation token flows through behaviors and handler
• Publish:
  • Resolve all handlers for the concrete notification type
  • Execute sequentially in resolver order
  • Stop on the first exception
• ServiceFactory:
  • A delegate-based abstraction for resolving services from any container (or your own resolver)

Out of scope (V1)

• Streaming requests / async enumerable responses
• Advanced publish strategies (parallelism, exception aggregation, fire-and-forget)
• Assembly scanning / auto-registration helpers
• Built-in logging/metrics (use pipeline behaviors instead)
• Licensing or license enforcement

Conceptual usage (high level)

1. Define a request type that implements IRequest<TResponse>.
2. Implement a handler for it using IRequestHandler<TRequest, TResponse>.
3. (Optional) Register one or more IPipelineBehavior<TRequest, TResponse> to wrap Send.
4. Provide a ServiceFactory that can resolve:
   • The request handler for the concrete request type
   • The pipeline behavior sequence for that request type
   • The notification handlers sequence for the concrete notification type
5. Create new Mediator(factory) and call Send / Publish.

Packaging

The library is designed to be packed as a NuGet package from src/DelegatR.

Examples

See examples/DelegatR.Examples.Console for a small console app demonstrating:

• Send with a request/handler
• Publish with two notification handlers (sequential execution)
• A simple pipeline behavior wrapping Send

Documentation

• documents/why-delegatr.md
• documents/migration-notes.md

License

MIT is recommended for this repository (add a LICENSE file when ready).