werkregie/doc/prs/2026-10-11-PR#19-pwa-offline.md

PR#19: The Last State Offline, Marked as Stale

WARNING: This document describes only the change applied in this PR. It may already be outdated once the next PR is merged. Historic PR documentation is not maintained along with new PRs; treat it as a snapshot.

Related Links

• werkregie PR#2: Werkregie as a PWA, step 1, the app shell offline.

Problem

The installed Werkregie starts without network, but shows empty panels: the service worker keeps the page only, never the data. On the road the user wants to see at least what was open the last time. mi decided on 2026-10-10 that the last state, with pull request and session data, may be kept in the browser's storage.

Non-Goals

• No caching of /api/ by the service worker.
• No push notifications.

Specification

Feature: the last state offline

Scenario#19.01: the page keeps each new state

… so that a later start without network has something to show.

• Given the server has a state with real data that the browser does not keep yet
• When the page loads /api/dashboard
• Then localStorage holds this state as werkregie-last

Verified by

• Manual: on port 4748, localStorage["werkregie-last"] held the generatedAt of the last answer, 166 kB.

Scenario#19.02: a start without the server shows the last state under a banner

… so that the user sees what was open, and how old it is.

• Given a kept state and a page without data
• When /api/dashboard fails
• Then the page shows the kept state, the indicator says "offline", and an amber banner says "Server nicht erreichbar – letzter Stand von HH:MM, vor …"

Verified by

• Manual: server on port 4748 stopped, state.data cleared, load() called: 38 pull request links and the banner "letzter Stand von 10:44, gerade eben".

Scenario#19.03: losing the server while the page is open keeps the shown state

… so that a short outage does not empty the page.

• Given the page shows live data
• When /api/dashboard fails
• Then the page keeps showing the data and the amber banner appears; it goes when the server answers again

Verified by

• Manual: server on port 4748 stopped with the page open: indicator "offline", banner shown, panels kept.

Scenario#19.04: demo data deletes the kept state

… so that no private data stays in a browser whose token the server no longer accepts.

• Given a kept state
• When the server answers with demo data
• Then localStorage holds no werkregie-last

Verified by

• Manual: a stubbed fetch answering access: "DEMO" deleted the kept state.

Scenario#19.05: forgetting the access token deletes the kept state

… so that no private data stays in a browser that gave its access up.

• Given a kept state and an access token in the browser
• When the user forgets the token with the key button
• Then localStorage holds no werkregie-last

Verified by

• Manual: the key button with a token cookie and a confirmed dialog deleted the kept state and the cookie.

Solution

• load() keeps each new answer in localStorage and, when the request fails, falls back to the kept one; the banner #stale-banner shows its time and age.
• The service worker stays as it was: it never touches /api/.
• dashboard/README.md and the Werkbaum describe the kept state.
• Version 0.8.0.

Open Questions

• Is a service worker start without network verified? Not in this PR: the embedded test browser does not register service workers. The node "Installed and checked on Android, iOS and desktop" stays planned for that check.

Additional Changes

• doc/prs/2026-10-11-PR#18-so-that.md gets its number in the title; it read "PR#0".