Heldinhow/dotnet-clean-architecture

.NET Clean Architecture

Overview

Clean Architecture organizes code into concentric layers with strict dependency rules, ensuring testability and maintainability. This skill should be invoked when building enterprise applications that require long-term maintainability, testability, and separation of concerns.

Core Principles

• Dependency Inversion: Dependencies point inward - domain has no dependencies
• Layered Structure: Domain, Application, Infrastructure, Presentation
• Business Logic in Domain: Core business rules live in the domain layer
• Abstractions: Use interfaces to define boundaries

Preparation Checklist

• [ ] Plan layer structure (Domain, Application, Infrastructure, Presentation)
• [ ] Define project structure
• [ ] Set up solution with multiple projects
• [ ] Configure dependency injection

Step-by-Step Process

1. Domain: Create Domain project with entities and interfaces
2. Application: Build Application project with use cases and DTOs
3. Infrastructure: Implement Infrastructure for databases, external APIs
4. Presentation: Create API endpoints in Presentation layer
5. Wire Up: Configure DI with interface implementations
6. Test: Write unit tests for domain and application layers

Do's and Don'ts

• ✅ Do keep domain layer free of external dependencies
• ✅ Do use interfaces for all external dependencies
• ✅ Do put business logic in application/domain layers
• ❌ Don't reference Infrastructure from Domain
• ❌ Don't mix concerns across layers
• ❌ Don't skip the abstraction layer

Anti-Patterns

• The Anemic Domain: Domain entities with no behavior
• Infrastructure Leak: Infrastructure code in domain layer
• Circular Dependencies: Breaking layer dependency rules
• Skipped Abstractions: Direct dependencies on concrete implementations