ESPresso (Tauri App)

Tauri 2 + React + TypeScript desktop app for sharing coffee profiles over any local network. The WiFi is the DNS — every device with ESPresso open hosts a pot, and pots on the same network find each other automatically via mDNS.

How it works

There is no hub device (the ESP32 is optional). Every app instance:

1. Hosts a pot server — a WebSocket server on port 8080 (8081–8086 if busy), advertised as _espresso._tcp.local. over mDNS with a unique hostname like espresso-<id>.local.
2. Discovers peers — every 15s it browses mDNS for other pots on the current WiFi and joins each one (a mesh).
3. Exchanges profiles — on connect, pots greet with hello + a full store snapshot. Profile updates are broadcast to the whole mesh and persisted to local SQLite (profiles.db).

Profiles converge across the network: you see everyone's profile, can add them as contacts, and your history keeps everything you've ever seen.

Architecture

src-tauri/src/
├── lib.rs      # Tauri commands, events, backend setup
├── models.rs   # serde data models (Profile, Contact, Device, HostInfo)
├── db.rs       # SQLite (rusqlite) with PRAGMA user_version migrations
├── mdns.rs     # mDNS discovery + advertising (mdns-sd)
├── server.rs   # PotServer: WS pot server, store, broadcast, hello+snapshot
└── ws.rs       # PotHub: hosts the server, joins peers, source-tagged store

src/
├── App.tsx          # thin React shell consuming commands/events
├── lib/espresso.ts  # typed invoke() + event wrappers
└── screens/         # presentational screens

• Database — rusqlite (bundled SQLite) at the app data dir. The old plugin-sql schema is detected and backed up to profiles.db.bak-<ts> before installing the clean schema.
• Profile store — every profile entry is tagged with its source (local / incoming client / outgoing peer), so when a peer's connection drops, only the profiles it contributed are removed. Full-store syncs use replace-by-source semantics, which makes the mesh converge — including removals.
• Events — the backend emits connection://status, profiles://updated (live mesh), contacts://updated, devices://updated and discovery://done.

Wire protocol (port 8080)

• Server → client on connect: { "type": "hello", "device_id": "…" } then { "type": "profiles", "data": [ { "device_id", "name", "role", "bio" } ] } (full store snapshot).
• Broadcasts: { "type": "profiles", "data": [...] } whenever the store changes.
• Client → server: either a single profile { "device_id", "name", "role", "bio" } (also compatible with an ESP32-style pot) or a full-store profiles message for mesh sync.

Development

npm install
npm run tauri dev

Open ESPresso on two devices on the same WiFi to see profiles sync. On a single machine you can also run two instances to test the mesh.