Backend Hexagonal Architecture

Layer Separation

domain/

• entities/: Domain models (MateriaPrima, Escandallo, Factura, etc.)
• ports/: Trait definitions (repository interfaces)
• services/: Pure business logic (coste calculation, rentabilidad)
• NO external dependencies (no Axum, no SQLx, no HTTP)

adapters/

• http/handlers/: HTTP request handlers
• http/dto/: Request/response DTOs
• http/middleware/: Auth middleware
• CAN import from domain and crate::repository

infrastructure/

• persistence/postgres/: Repository trait implementations
• ocr/: OCR service implementations
• unpispas_client/: unpispas API client
• config.rs: Environment configuration

Import Rules

• Handlers MUST use crate::repository, NEVER crate::infrastructure::persistence::postgres
• Domain layer MUST NOT import from adapters or infrastructure
• crate::error::AppError is the only error type in handler return types