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RA.Utilities.Feature.Models

Namespace: RA.Utilities.Feature.Models

The RA.Utilities.Feature.Models namespace primarily defines delegates that are fundamental to implementing the pipeline behaviors within the RA.Utilities.Feature library.

✨ Here's a breakdown of their purpose:​

1. NotificationHandlerDelegate:​

  • Purpose: This delegate represents an asynchronous callback that invokes the next INotificationHandler(s) in the notification processing pipeline.
  • Usage: It's used within INotificationBehavior implementations (like NotificationLoggingBehavior) as the next parameter. When a behavior calls await next(), it's essentially telling the pipeline to proceed with the execution of the actual notification handlers or the next behavior in the chain. This allows behaviors to execute logic both before and after the core notification handling.

2. RequestHandlerDelegate and RequestHandlerDelegate<TResponse>:​

  • Purpose: These delegates represent asynchronous callbacks for invoking the next IRequestHandler(s) in the request processing pipeline. They are designed to work seamlessly with the Result pattern from RA.Utilities.Core.
  • RequestHandlerDelegate(): Used for requests that do not return a specific data type, but still need to indicate success or failure using Result.
  • RequestHandlerDelegate<TResponse>(): Used for requests that are expected to return a specific data type (TResponse), wrapped in a Result<TResponse> to indicate success or failure.
  • Usage: They are used within IPipelineBehavior implementations (like ValidationBehavior) as the next parameter. Similar to NotificationHandlerDelegate, calling await next() allows the pipeline behavior to pass control to the subsequent handlers or behaviors, enabling the application of cross-cutting concerns (e.g., validation) before and after the main request handling logic.

🧠 Summary​

In essence, the classes (which are delegates in this case) in RA.Utilities.Feature.Models provide the necessary contractual types for building flexible and extensible processing pipelines for both notifications and requests, enabling the "middleware" pattern for CQRS and event-driven architectures.