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[ and ] needed a reach/shift on most layouts and felt awkward next to the otherwise all-unshifted control scheme (hjkl, space, digits). , and . are adjacent, unshifted, easy to hit without looking away from the canvas -- a natural prev/next pair. Old bindings kept as a fallback rather than removed. Verified both in isolation (Update() with a KeyMsg) and live over a real SSH session -- the status-line ink swatch visibly cycles from █ to ▓ on a fresh connection. An initial live test after the rebind appeared to fail, but that traced to a stale session left over from the server restart, not an actual bug -- confirmed working correctly on a fresh connection. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
72 lines
2.7 KiB
Markdown
72 lines
2.7 KiB
Markdown
# scrawl
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A shared ASCII doodle wall you connect to over SSH. Everyone connected
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right now is drawing on the same canvas, live.
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```
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ssh scrawl.goonk.se -p 23235
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```
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Not aiming to be useful to anyone but me — built purely because a
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multiplayer canvas over raw SSH is a genuinely fun, weird shape for a
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toy, and the `wish`+`bubbletea` pattern from
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[delve-term](https://repo.explewd.com/explewd/delve-term) was still
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fresh enough to reuse without re-learning it.
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## Controls
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- Arrow keys or `hjkl` — move your cursor
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- `space` / `enter` — paint
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- `backspace` / `delete` — erase
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- `,` / `.` — cycle the ink character (`[` / `]` also work)
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- `1`-`8` — pick a color
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- `c` — clear the whole canvas (yes, for everyone — it's a shared wall)
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- `q` / `ctrl+c` — quit
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## Architecture
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Same security model as `delve-term`: the SSH server
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([`charmbracelet/wish`](https://github.com/charmbracelet/wish)) hands
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each connection straight to a [bubbletea](https://github.com/charmbracelet/bubbletea)
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program — no shell, no exec, structurally can't reach a real shell on
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the host.
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The one thing this app needed beyond `delve-term`'s pattern: multiple
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sessions sharing live state. `wish`'s `bm.Middleware` helper hides the
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`*tea.Program` it creates behind its own closure, so this app builds the
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program directly instead, keeping a reference in a small registry
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(`game.Canvas`) that broadcasts a redraw signal to every *other*
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connected session the instant one of them paints.
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A real bug worth knowing about if you're extending this: `Program.Send()`
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blocks until that program's `Run()` event loop is actively reading from
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it. Broadcasting synchronously from inside `Join()`/`Paint()` deadlocked
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every session before it ever reached `Run()` — fixed by sending
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asynchronously (`go p.Send(...)`) everywhere the canvas notifies
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sessions of a change.
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A second, subtler bug: `lipgloss`'s default styles detect color support
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from the *server process's* `os.Stdout`, not any given session's actual
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terminal — and a server's stdout is typically redirected (a log file, a
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systemd journal), so every session silently lost all color/background
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styling at once. Fixed with a `lipgloss.Renderer` created per-session,
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bound to that session's actual output, forced to `TrueColor`.
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## Local development
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```bash
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./run-local.sh # starts on :23235
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ssh -p 23235 localhost -o StrictHostKeyChecking=no # in another terminal
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```
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## Status
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Verified with two simultaneous SSH sessions (scripted, not just live
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poking) — one paints, the other sees it via the broadcast, peer count
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stays in sync. No persistence: canvas state lives in memory only and
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resets on restart, which is fine for what this is.
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## License
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MIT.
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