rmaps-online/backlog/tasks/task-4 - PWA-offline-support.md

id	title	status	assignee	created_date	updated_date	labels	dependencies	priority
task-4	PWA offline support	Done		2025-12-15 19:37	2026-01-02 16:15			high

Description

Implement service worker for offline caching. Store map tiles, venue data, and room state in IndexedDB. Sync when reconnected.

Implementation Notes

Partial Implementation

PWA basics implemented:

1. Service Worker (public/sw.js)

   • Push notification handling
   • Location request messaging
   • Basic caching setup

2. Install Banner (src/components/room/InstallBanner.tsx)

   • Detects installable PWA state
   • Shows "Add to Home Screen" prompt
   • iOS-specific instructions
   • Dismissible with localStorage persistence

3. PWA Manifest - App manifest with icons and theme colors

Still Needed

• Offline map tile caching (IndexedDB)
• Room state persistence for offline viewing
• Sync queue for offline location updates
• Background sync when reconnected

Offline Support Completed

Implemented comprehensive PWA offline support:

1. Multi-Strategy Service Worker Caching:

   • App shell precaching for instant loading
   • Map tiles cache-first with background refresh (max 500 tiles)
   • API requests network-first with cache fallback
   • Static assets stale-while-revalidate

2. IndexedDB Room State Persistence:

   • saveRoomState() and getRoomState() for offline storage
   • Room state sync in useRoom hook
   • Saves state to SW on changes
   • Loads cached state on initial load for offline fallback

3. Message Handlers:

   • SAVE_ROOM_STATE - persist room data
   • GET_ROOM_STATE - retrieve cached data
   • CLEAR_CACHES - manual cache clearing

Deployed to production on 2026-01-02.