Home screen is the first surface on app open; without a local cache
the cold-start blocks on /api/home, which dominates felt latency on
slow or remote connections. This commit caches the last successful
HomeData as a single-row JSON blob in drift, so subsequent app opens
yield content immediately and revalidate in the background.
Schema:
- New CachedHomeSnapshot table (single row: id=1, json TEXT,
updated_at). schemaVersion bumped 2 → 3 with a forward migration
that calls m.createTable(cachedHomeSnapshot). Codegen regenerated
via build_runner; the *.g.dart files are gitignored and rebuilt
by the CI Codegen step.
Provider rewrite:
- homeProvider: FutureProvider<HomeData> → StreamProvider<HomeData>
using the existing cacheFirst<CachedHomeSnapshotData, HomeData>
pattern (alwaysRefresh: true for SWR). On cold cache the first
/api/home fetch populates the row. On warm cache the cached
HomeData is yielded immediately and a background REST fetch
overwrites the row, which drift's watch() picks up.
- Encoder helpers (_albumToJson / _artistToJson / _trackToJson) so
HomeData survives the JSON round-trip into and out of drift.
Field names match the server's /api/home wire shape exactly so
HomeData.fromJson handles both fresh server responses and cached
drift rows.
Callers untouched: home_screen.dart's ref.watch + ref.refresh +
metadata_prefetcher's ref.listen all keep working with the
StreamProvider shape (AsyncValue<HomeData> stays the surface type).
Test fix: 4 homeProvider.overrideWith sites in home_screen_test.dart
switched from `(ref) async => _emptyHome` (FutureProvider form) to
`(ref) => Stream.value(_emptyHome)` (StreamProvider form).
For #357. Completes the user-visible deferred follow-up. Remaining
deferred items: library_changes server-side retention.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen
22bd06a578