Server Architecture¶

The server follows clean architecture with four layers.

Dependency Rule¶

graph TD
    P[Presentation] --> A[Application]
    A --> D[Domain]
    I[Infrastructure] --> D
    I --> A
    P --> I

Dependencies always point inward. The domain layer has zero external dependencies.

Layer Responsibilities¶

Domain¶

• Entities and value objects
• Repository traits (interfaces)
• Domain errors
• Business rules that are always true regardless of use case

Application¶

• Use cases (one struct per use case)
• DTOs for input/output
• Service traits
• Application-level error types
• Orchestrates domain objects — no direct DB or HTTP knowledge

Infrastructure¶

• SQLx repository implementations
• JWT token service
• External API clients
• Anything that talks to the outside world

Presentation¶

• Actix-web route handlers
• Request/response types (serde)
• Middleware (auth, logging, error handling)
• Askama template rendering
• Dependency injection wiring (in main.rs)