Dmitry
ffc5ed959a
CacheInterceptor кэширует каждый успешный GET по путь+параметры в drift (sqlite нативно, wasm+OPFS в браузере) и подменяет им сетевую ошибку; провайдер отдаёт Cached<T>, экран показывает баннер «данные на …». Контракт для остальных экранов — docs/ai/offline-cache.md. flake.nix: libsecret/pkg-config для линуксовой сборки, jq/curl для just app-web-assets (сборка sqlite3.wasm + drift_worker.js).
72 lines
2.5 KiB
Dart
72 lines
2.5 KiB
Dart
import 'dart:convert';
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import 'package:drift/drift.dart';
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import 'package:drift_flutter/drift_flutter.dart';
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part 'response_cache.g.dart';
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/// The last successful body of one GET, keyed by endpoint+params exactly as
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/// [CacheInterceptor] builds the key. See `docs/ai/offline-cache.md` for the
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/// whole contract this table is part of.
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class CachedResponses extends Table {
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TextColumn get requestKey => text()();
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TextColumn get body => text()();
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DateTimeColumn get fetchedAt => dateTime()();
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@override
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Set<Column> get primaryKey => {requestKey};
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}
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/// A cached body plus when it was fetched — what [CacheInterceptor] needs to
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/// rebuild a synthetic [Response] when the network itself is unreachable.
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///
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/// Not named `CachedResponse`: drift already generates a row class with that
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/// name for the `CachedResponses` table above.
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class CacheEntry {
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const CacheEntry(this.body, this.fetchedAt);
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final Object? body;
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final DateTime fetchedAt;
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}
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@DriftDatabase(tables: [CachedResponses])
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class ResponseCacheDatabase extends _$ResponseCacheDatabase {
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ResponseCacheDatabase() : super(_openConnection());
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ResponseCacheDatabase.forTesting(super.executor);
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@override
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int get schemaVersion => 1;
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/// Replaces whatever was cached for [requestKey] — one row per endpoint+params,
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/// never a history.
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Future<void> put(String requestKey, Object? body) => into(cachedResponses).insertOnConflictUpdate(
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CachedResponsesCompanion.insert(
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requestKey: requestKey,
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body: jsonEncode(body),
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fetchedAt: DateTime.now(),
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),
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);
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/// The body last stored for [requestKey], or null if this endpoint+params was
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/// never fetched successfully on this device.
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Future<CacheEntry?> get(String requestKey) async {
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final row = await (select(
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cachedResponses,
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)..where((t) => t.requestKey.equals(requestKey))).getSingleOrNull();
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if (row == null) return null;
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return CacheEntry(jsonDecode(row.body), row.fetchedAt);
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}
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}
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/// One sqlite file via native FFI on Android/iOS/desktop; wasm+OPFS (falling
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/// back to IndexedDB) on web — `driftDatabase` from `package:drift_flutter`
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/// picks the right backend, `web/sqlite3.wasm` and `web/drift_worker.js` are
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/// the compiled assets it loads there (regenerate with `just app-web-assets`
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/// whenever the `drift`/`sqlite3` package versions change).
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QueryExecutor _openConnection() => driftDatabase(
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name: 'response_cache',
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web: DriftWebOptions(
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sqlite3Wasm: Uri.parse('sqlite3.wasm'),
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driftWorker: Uri.parse('drift_worker.js'),
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),
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);
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