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HandlerRegistrations

Namespace: RA.Utilities.Feature.Generated

HandlerRegistrations is the runtime-side queue that the handler registration source generator feeds: every assembly referencing the package emits a module initializer that queues the DI registrations of its handlers and closed pipeline behaviors.

🎯 Purpose​

Handlers and behaviors live in your assemblies, so the runtime package cannot reference them directly. The queue bridges that gap:

  1. At assembly load, the generated module initializer queues one registration callback for the assembly.
  2. Your startup code calls services.AddMediator().
  3. AddMediator applies every queued callback, registering:
    • request handlers — scoped, under IRequestHandler<...> and as themselves,
    • notification handlers — transient, under INotificationHandler<...> and as themselves,
    • closed pipeline behaviors (IPipelineBehavior<,>, IPipelineBehavior<>, INotificationBehavior<>) — transient, as themselves only, so the generated mediator can inject them directly by concrete type.

⚙️ Members​

public static class HandlerRegistrations
{
    /// <summary>Queues a handler-registration callback. Called by generated module initializers.</summary>
    public static void Add(Action<IServiceCollection> registration);

    /// <summary>Applies all queued registrations. Called by AddMediator().</summary>
    internal static void ApplyAll(IServiceCollection services);
}

You never call Add yourself — it is for the generated initializer. See the Auto Registration guide for the discovery rules, lifetimes, and the FEAG001–FEAG005 diagnostics.

🧠 Summary​

HandlerRegistrations carries the zero-config registrations from the source generator to AddMediator(). Its sibling MediatorRegistrations carries the generated mediator registration through the same pattern.