Bsft.Mediator.Abstractions 2.2.0

Bsft.Mediator.Abstractions

The CQRS contract of the Bsft.Mediator family: the message markers (ICommand, IQuery, INotification), the handler interfaces, IMediator and the pipeline seam. Reference this from a module that declares messages and handlers; the host references the implementation.

Install

dotnet add package Bsft.Mediator.Abstractions

Requires nothing. That is the point: a domain assembly that declares CreateOrderCommand and its handler compiles against this package alone and never acquires a dispatcher, a container or a logger.

Register

// Nothing. An .Abstractions package has no DI entry point.
services.AddBsftMediator(m => m.RegisterServicesFromAssembly(typeof(CreateOrderCommand).Assembly));

Nothing else is required here. The host registers the implementation from Bsft.Mediator, pointing it at the assemblies whose handlers it should find.

Configure

Validation: none — the package registers nothing.

Extend

IMediator — dispatches a command, query or notification to its handler. ICommandHandler<TCommand> / ICommandHandler<TCommand, TResult> / IQueryHandler<TQuery, TResult> / INotificationHandler<TNotification> — what an application implements. The framework finds them by assembly scan, so the interface is the whole registration contract. IPipelineBehavior<TRequest, TResponse> — wraps a dispatch. Logging, tracing, transactions, validation, caching and resilience are all behaviors, and so is anything cross-cutting you add. INotificationForwarder — receives every published notification, for bridging the mediator onto another transport; Bsft.Mediator.EventAggregator implements it over the in-process aggregator. IRequestMetadataProvider / IRequestMetadata — the concrete type of a dispatched request and the attributes on it, cached per request type. A behavior is closed over ICommand<TResult>, so an attribute on the message is invisible to its type parameter; this is where an attribute-driven behavior reads it instead of keeping a reflection cache of its own. Bsft.Mediator registers the implementation. ICorrelationIdAccessor — supplies the id the logging and tracing behaviors stamp onto a dispatch, without this package depending on the correlation family.

TransactionalAttribute on a handler is what TransactionBehavior looks for; a request whose handler does not carry it is dispatched outside a transaction.

Documentation

Topic page: docs/mediator.md. Conventions: docs/package-conventions.md.