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RaTemplate.Api

The RaTemplate.Api project is the presentation layer and the entry point of the application. In a Clean Architecture design, this is the outermost layer, responsible for exposing the application's functionality to the outside world via a Web API. It handles all HTTP-specific concerns and translates incoming requests into calls to the Application layer.

This project is the "delivery mechanism." It knows how to communicate over web protocols but contains no business logic itself.

🎯 Purpose and Key Responsibilities​

The primary purpose of the Api layer is to handle web requests and act as the composition root for the entire application.

This project is responsible for:

  • Exposing API Endpoints: It defines the API endpoints that clients will interact with. This template uses a feature-based approach with Minimal APIs.
  • Handling HTTP Requests/Responses: It receives HTTP requests, deserializes request bodies into DTOs or CQRS commands/queries, and serializes the results from the Application layer back into HTTP responses.
  • Orchestrating Application Logic: It calls into the Application layer (typically using a mediator pattern like MediatR) to execute the relevant use case.
  • Composition Root: This is where all the application's services are "wired up." The Program.cs and StartupExtensions.cs files configure the dependency injection container, registering services from the Application and Infrastructure layers.
  • Implementing Web-Specific Cross-Cutting Concerns: It handles concerns that are specific to the web layer, such as:
    • Global exception handling (translating exceptions to appropriate HTTP status codes).
    • Authentication and Authorization middleware.
    • Configuring and serving OpenAPI (Swagger/Scalar) documentation.
    • CORS policies and rate limiting.

🏛️ Architectural Principles​

  • Dependency Rule: This project depends on the Application and Infrastructure projects. This is necessary because it acts as the composition root, where all dependencies are registered. The flow of control, however, still follows the Dependency Rule: Api calls Application, which calls Domain.

  • No Business Logic: This layer should be "thin." It should not contain any business rules or domain logic. Its job is to simply pass requests to the Application layer and return the result.

  • UI-Specific: All code in this project should be related to the API. If you were to create a different type of UI (e.g., a gRPC service or a Blazor Web App), you would create a new presentation layer project, and it would replace this one, while the Core (Domain and Application) layers would remain unchanged.

📦 Contents​

A typical RaTemplate.Api project includes the following:

  • Program.cs: The main entry point of the application where the web host is configured and started.
  • StartupExtensions.cs: Contains extension methods to keep Program.cs clean by organizing service registration and middleware configuration.
  • Endpoints/: Organizes API endpoints by feature, promoting a clean and scalable structure.
  • Extensions/: Contains extension methods for configuring specific services like Authorization or OpenAPI.
  • appsettings.json: Configuration files for the application.