# Internal Architecture

OxiCloud follows a **hexagonal (ports & adapters) architecture** with four layers:

```
┌───────────────────────────────────────────────────────────────┐
│  Interfaces    │ REST API, WebDAV, CalDAV, CardDAV, WOPI      │
├───────────────────────────────────────────────────────────────┤
│  Application   │ Use cases, DTOs, port definitions            │
├───────────────────────────────────────────────────────────────┤
│  Domain        │ Entities, business rules, repository traits  │
├───────────────────────────────────────────────────────────────┤
│  Infrastructure│ PostgreSQL, filesystem, caching, auth        │
└───────────────────────────────────────────────────────────────┘
```

All cross-layer dependencies point **inward** via trait-based ports. The DI container (`AppServiceFactory`) wires concrete implementations at startup.

## Storage Model: 100% Blob Storage

- **File metadata** (name, folder, size, user, timestamps, trash status) → PostgreSQL (`storage.files`)
- **File content** → content-addressed blobs via DedupService at `.blobs/{prefix}/{hash}.blob`
- **Folder structure** → purely virtual, rows in `storage.folders` (no filesystem directories per user)
- **Trash** → soft-delete flags on files/folders, exposed via `storage.trash_items` VIEW

## Dependency Injection

`AppServiceFactory` in `src/common/di.rs` builds all services in a defined order:

1. **Core services** — paths, content cache, thumbnails, chunked upload, transcode, dedup, compression
2. **Repositories** — `FolderDbRepository`, `FileBlobReadRepository`, `FileBlobWriteRepository`, `TrashDbRepository`
3. **Trash service** (if enabled)
4. **Application services** — folder, file upload/retrieval/management, search, i18n
5. **Share service** (if enabled)
6. **DB services** — favorites, recent, storage usage, auth
7. **CalDAV/CardDAV services**
8. **ZIP service** (last, depends on file & folder services)
9. **Assemble `AppState`**

## Project Structure

```
src/
├── common/          # Config, DI container, errors
├── domain/          # Entities, repository traits
├── application/     # Use cases, DTOs, port traits
├── infrastructure/  # PostgreSQL repos, filesystem, caching
└── interfaces/      # HTTP handlers, WebDAV, CalDAV, CardDAV
```

## Key Metrics

| Metric | Value |
|--------|-------|
| Rust source files | ~170 |
| Lines of code | ~50 000 |
| Automated tests | 222+ |
| Docker image | ~40 MB |

## Further Reading

- [Caching Architecture →](/architecture/caching)
- [Storage Quotas →](/architecture/storage-quotas)