The kiosk mode should function when there is no connection. - When online, function as normal - Locally store cache of app/UI - Locally store cache of users and products - Locally store uncommitted transaction until back online When connection is lost, a user should still be able to: - Use the kiosk interface - Search products (basic) - Search users (basic) - Place oders To prevent duplicate transactions, we may assign an unique ID to each uncommitted transaction to identify them. ## Tasks - [x] Basic workbox offline configuration - [x] Set up basic cache routes for kiosk network requests - [x] Update cache limits - [x] Make `/` redirect to `/kiosk` - [x] ~~Make other unknown requests route to `/kiosk`~~ (not possible right now) - [x] Warm cache for common URLs (`/`, `/kiosk`) - [x] Warm cache for all users/products - [x] On search, fall back to all user/product cache - [x] How are buy requests cached? - [x] Show buy request queue counter? - [x] Separate service worker for kiosk mode - [x] Show nice offline banner in kiosk (msg: offline, transactions delayed) - [x] Try to drain queue on connection - [x] ~~Retry to drain queue after a while on failure (too many requests)~~ (not required, interface reloads after 15 minutes) - [x] ~~Remove `alert()` on failure, show banner instead~~ (https://gitlab.com/timvisee/barbapappa/-/issues/636) - [x] ~~Disable CSRF on buy endpoint?~~ (probably not required) - [x] Disable rate limiting on buy endpoint? (not disabled, but increased) - [x] Make sure kiosk auto-reload doesn't break offline mode/cache - [x] Add UUID to transaction - [x] ~~Validate UUID uniqueness~~ (https://gitlab.com/timvisee/barbapappa/-/issues/637)