Henrik Lemke
a82b38d725
A fourth front-end next to shell, desktop and lab/voila: one gateway process in the session (tornado, own thread, 127.0.0.1 + token), many thin browser clients. Values via live_values.LiveReader and writes via start_write, as in the Qt and ipywidgets grids; writes off by default. Namespace list with lazy init, device grid, SVG panels, reconnect, installable as an app. Nothing imports eco.web; start it with eco.web.start_web() or try it with python -m eco.web --demo. Plan, protocol and status in web_frontend/.
eco web front-end (PWA)
A fourth eco front-end, a Progressive Web App (an installable web page, touch-first, works on a phone), next to and independent of the other three:
| Front-end | Process model | Strength |
|---|---|---|
shell (IPython) |
the session | everything, for experts |
desktop (Qt) |
in-process with the session | full-featured workbench on a console |
lab / voila (ipywidgets) |
one kernel per viewer | notebooks, interactive exploration |
web (PWA) |
one gateway process, many thin clients | phones/tablets/laptops, remote via SSH tunnel |
Status (2026-10-30): spike implemented, not wired into eco
The code is in eco/web/ and tests/test_web_*.py. Nothing else in eco
imports it — not eco/__init__.py, not eco_cli.py, not pyproject.toml —
so it can't affect other work and can be developed alongside it. It's
switched on only by explicitly calling it (below). Wiring it in (an
eco.start_web() wrapper, --ui web, an eco[web] extra, package-data for
eco/web/static/) is a separate small step once the test on the beamline
went well — see SPIKE.md.
What works (tested against the simulated namespace, and in headless Chrome at phone size):
- namespace list (initialized / lazy / failed with reason), filter, tap a lazy component to initialize it
- device view: an assembly's display rows (hidden ones behind a toggle), live
values via
eco.widgets.live_values.LiveReader(monitored where possible, polled otherwise — the same engine as the Qt and ipywidgets grids), status dot, value age and staleness, units, open/closed colouring - writes, only when the gateway was started with them: ▲/▼ with step,
absolute move (dialog), enum select, Stop, triggers (confirmed) — through
set_target_value, so the access gate and queue claims apply - SVG panels (
_widget_svg_panel/_show_svg), live-refreshed, sanitized; a tap on a device opens its view (the// eco: <cmd>commands are not run) - token auth + HttpOnly cookie, binds 127.0.0.1, ping/reconnect after network drops, clean shutdown, service worker (app shell only), light/dark
Not yet: queues/scan progress, cameras, plots, alarms, dashboards, status-server (shared, read-only) mode, the monospace-label convention of the static beamline SVG. See PARITY.md for the order.
Try it
Anywhere, without a beamline (simulated motors, valves, an SVG panel, a slow and a broken component):
python -m eco.web --demo # read-only
python -m eco.web --demo --writes # with writes
In a running eco session (uses the session's namespace):
from eco.web import start_web, stop_web
gw = start_web() # read-only; prints the URL with the token
gw = start_web(writes=True) # writes from the browser allowed
stop_web()
Open the printed http://localhost:8097/?token=…. From another machine, forward
the port first: ssh -L 8097:localhost:8097 <host> (plus your usual jump host).
Always use the same local port: browser storage and the installed app are per
localhost:<port>.
Tests (per file, like the rest of the suite):
PYTHONPATH=$PWD python -m pytest tests/test_web_viewmodels.py -q
PYTHONPATH=$PWD python -m pytest tests/test_web_client_session.py -q
PYTHONPATH=$PWD python -m pytest tests/test_web_gateway.py -q # needs tornado
Documents
- ARCHITECTURE.md — gateway, hosting modes, how the UI families stay in step, security, SSH.
- PARITY.md — every Qt feature, its PWA cost, what stays Qt-only.
- PROTOCOL.md — the wire protocol (v0, implemented).
- SPIKE.md — the beamline test: prerequisites, procedure, go/no-go.
Code map
eco/web/__init__.py start_web() / stop_web() / connection_help()
eco/web/__main__.py python -m eco.web --demo
eco/web/gateway.py tornado app on its own thread: token, static, /api/svg, /ws
eco/web/client_session.py one client: the protocol, LiveReader, writes (no transport)
eco/web/viewmodels.py eco objects/values -> plain JSON (no tornado)
eco/web/backends.py SessionBackend (a live namespace); status-server backend later
eco/web/demo.py simulated namespace
eco/web/static/ index.html, app.js, style.css, sw.js, manifest, icon (no build step)