Intent.Application.MediatR.Behaviours

What This Module Does

Adds cross-cutting MediatR pipeline behaviours to your application request handling pipeline: logging, performance measurement, authorization, unit of work commit, unhandled exception capture, and event bus publication.

Generated Behaviours

  • LoggingBehaviour<TRequest,TResponse>: Logs request start/end, may include correlation and serialized request snapshot.
  • PerformanceBehaviour<TRequest,TResponse>: Times request execution; can warn when exceeding threshold (implementation specific).
  • AuthorizationBehaviour<TRequest,TResponse>: Enforces [Authorize] attribute semantics or role/claim requirements using ICurrentUser.
  • UnhandledExceptionBehaviour<TRequest,TResponse>: Catches unhandled exceptions, logs, optionally rethrows or wraps.
  • UnitOfWorkBehaviour<TRequest,TResponse>: Ensures transactional commit (via IUnitOfWork) after successful handler execution.
  • EventBusPublishBehaviour<TRequest,TResponse>: Publishes integration/domain events registered during request handling via IEventBus.

Order & Composition

MediatR executes behaviours in registration order (outer → inner). Typical ordering strategy:

  1. Logging / Performance (outer)
  2. Authorization
  3. UnhandledException
  4. UnitOfWork
  5. EventBus publication (inner, after success)

Dependencies

  • Intent.Application.Identity for ICurrentUser used by AuthorizationBehaviour.
  • Intent.Common.UnitOfWork and repository abstractions for UnitOfWorkBehaviour.
  • Intent.Eventing.Contracts (via Application Eventing) for EventBusPublishBehaviour.
  • Intent.Application.DependencyInjection.MediatR for registration of behaviours into DI container.

Interoperability Detectors

Imodspec declares minimum versions for optional persistence/state modules (CosmosDB, MongoDb, Dapr State) to ensure compatibility when behaviours interact with their transactions / contexts.

Customization Points

  • Adjust logging detail (redaction, correlation IDs) by editing merge-mode partial class.
  • Inject metrics/tracing (OpenTelemetry) inside PerformanceBehaviour.
  • Authorization rules extension: custom attributes / policies.
  • Event bus behaviour can filter or batch events.

When To Use

  • Medium/large applications seeking consistent cross-cutting concerns without scattering logic.

When Not To Use

  • Extremely small or script-like projects; pipeline overhead unnecessary.
  • Intent.Application.Identity
  • Intent.Eventing.Contracts
  • Intent.Application.DependencyInjection