Crates

The backend is a Cargo workspace with four crates. Dependencies flow strictly downward.

shared

Pure types with no business logic. Depends on nothing.

Contains:

• DTOs (request/response types)
• Error types (ProblemDetails — RFC 7807)
• Validation utilities
• Pagination types
• Common enums shared between layers

Key files:

• src/lib.rs — Re-exports
• src/types.rs — Core type definitions
• src/problem_details.rs — Error response format

domain

Business logic layer. Defines traits that infra implements.

Contains:

• Entity definitions (entities.rs)
• Repository traits (repositories.rs) — CaseRepository, ParticipantRepository, etc.
• Domain services (services/) — Business rules, calculations
• Document processing — Block types, DOCX export, variable resolution
• Template evaluation engine

Key patterns:

• Repository traits use async_trait with Send + Sync
• Services accept Arc<dyn RepositoryTrait> for DI
• Entities use Uuid IDs and chrono::DateTime<Utc> timestamps

Key files:

• src/entities.rs — All entity structs
• src/repositories.rs — All repository trait definitions
• src/services/ — Business logic implementations

infra

Infrastructure layer. Implements domain traits with concrete technologies.

Contains:

• PostgreSQL repositories (postgres/) — sqlx-based implementations
• Email providers (SMTP, Microsoft Graph)
• LDAP client
• TOTP (2FA)
• Image processing (signatures)
• File storage (encrypted)
• Export (CSV, PDF)
• Seeding (templates, demo data)
• Legacy migration (SQL Server)

Key patterns:

• Each repository in postgres/ implements a domain trait
• Queries use sqlx::query! or sqlx::query_as! with compile-time checking
• Connection pooling via sqlx::PgPool

Key files:

• src/postgres/ — One file per repository
• src/seeding/ — templates.rs, demo.rs
• src/email.rs — SMTP and Graph providers
• src/storage.rs — Encrypted file storage

Binaries:

• src/bin/seed_demo.rs — Demo data seeder (cargo run --bin seed-demo)

api

HTTP layer. Axum handlers, router, middleware.

Contains:

• Route handlers (handlers/) — One file per resource
• Router configuration (router.rs)
• Application state (state.rs) — Holds all Arc<dyn Trait> services
• Middleware (auth, CORS, logging)
• WebSocket support

Key patterns:

• Handlers extract from Axum (Json<T>, Path<Uuid>, Query<T>)
• Auth via JWT middleware (AuthUser extractor)
• Responses use ProblemDetails for errors (RFC 7807)
• All request/response types use #[serde(rename_all = "camelCase")]

Key files:

• src/main.rs — Server entry point
• src/router.rs — Route definitions
• src/state.rs — AppState with 35+ injected services
• src/handlers/ — One handler file per resource