Build log · Software & apps

WiFi Chat

Software & appsdone4 versionsFastAPIWebSocketTunnelFile SharingDevice Detection
📄 Raw spec (.md)📁 Portfolio

reflection not written yet · every fact below is generated from this project’s own spec and files

What it is

Anonymous chat that works anywhere — FastAPI + WebSocket behind an SSH reverse tunnel, so friends on any network join via a short da.gd link. Shares any file up to 50MB and shows the host each device's type, brand, OS and browser. When the host closes the tab, the room blanks instantly for everyone.

Version history

Straight from the project’s own card data — what each version added.

V1

LAN text chat.

V2

Internet tunnel + short links.

V3

File sharing + device detection.

V4

Instant blank on host-leave.

What broke, and what I’d change

Not written yet. This is the part only I can write — what actually went wrong, and what I’d do differently. It lives in builds/reflections/wifi-chat.md (see _TEMPLATE.md); as soon as that file has words in it, this section fills in on the next build.

Everything else on this page — the spec, the version history, the file counts — is generated from the project’s own build notes and files, so nothing here is guesswork.

Build spec

The project’s own build notes, rendered. Open the raw .md ↗

Show the spec

WiFi Chat

Category: Software & Apps · Status: Done

Anonymous chat that works anywhere — FastAPI + WebSocket behind an SSH reverse tunnel, so friends on any network join via a short da.gd link. Shares any file up to 50MB and shows the host each device's type, brand, OS and browser.

Stack / Tools: FastAPI, WebSocket, localhost.run, da.gd, python-multipart

Build path:

  • V1 — LAN text chat.
  • V2 — Internet tunnel + short links.
  • V3 — File sharing + device detection.
  • V4 — Instant blank on host-leave.

Location: ~/Desktop/wifi-chat/

Anonymous chat where Isaac is always the host. Anyone anywhere joins through a short link — no same-WiFi requirement (the school WiFi blocks device-to-device, so the launcher spins up an SSH reverse tunnel through localhost.run and shortens the .lhr.life URL with da.gd using unambiguous characters only).

How it works

  • launcher.py starts uvicorn, opens the tunnel, fetches a short URL, pops a dialog, opens the browser.
  • server/main.py — FastAPI app: /health, /link, /upload, WebSocket /ws. Host claims with a secret host_token from the URL; host sees the 👥 admin panel.
  • server/chat_manager.py — ChatUser dataclass + user-agents library detects device type/brand/OS/browser (iPhone, Android Phone, Mac, Windows…).
  • client/index.html — single-file HTML5 client, no build step.

Key decisions

  • Host detection via secret URL token (not IP) — the host opens the LAN link, so IP-matching broke.
  • .command launcher (not AppleScript .app) — the .app silently failed to open Terminal.
  • da.gd is the only shortener that accepts .lhr.life; custom unambiguous codes avoid 0/1/I/l/O confusion.
  • File sharing: UploadFile POST to /upload, then a file_share WebSocket broadcast. MIME field is named mime (not type) because type collides with the message-type field.
  • Host-leave: grace period 0 → instant chat_ended broadcast → client hides the whole app and shows a blank white screen.

Pitfalls

  • python-multipart must be installed or /upload throws RuntimeError: Form data requires "python-multipart".
  • File MIME must NOT reuse the type key in the WS payload.
  • Tunnel dies when the Mac sleeps; the launcher re-runs are cheap.