feature-storage

Feature: Storage

Purpose: Fetch files from Firebase Storage with automatic transparent caching in SharedPreferences. Provides two notifiers and two widgets that handle the full fetch → cache → display lifecycle, including configurable cache invalidation by date or duration.

---

Layer Map

lib/src/features/storage/
├── domain/
│   ├── repositories/storage_repository.dart           # abstract StorageRepository (with built-in cache logic)
│   ├── data_sources/storage_remote_data_source.dart   # abstract StorageRemoteDataSource
│   └── usecases/
│       ├── get_download_url_usecase.dart               # GetDownloadUrlUsecase + provider
│       └── get_json_usecase.dart                       # GetJsonUsecase + provider
├── data/
│   ├── repositories/firebase_storage_repository.dart  # FirebaseStorageRepository + provider
│   └── data_sources/
│       └── firebase_storage_remote_data_source.dart   # FirebaseStorageRemoteDataSource + provider
└── presentation/
    ├── notifiers/
    │   ├── get_download_url_state_notifier.dart        # GetDownloadUrlStateNotifier + provider
    │   └── get_json_state_notifier.dart                # GetJsonStateNotifier + provider
    └── widgets/
        ├── image_network_from_storage_widget.dart      # ImageNetworkFromStorageWidget
        └── svg_from_storage_widget.dart                # SvgFromStorageWidget

---

Domain

StorageRepository — Abstract With Built-In Cache Logic

File: lib/src/features/storage/domain/repositories/storage_repository.dart

Unlike other repositories, StorageRepository is abstract but not empty — it contains the full cache-or-fetch logic directly using forwardedCachedGet:

abstract class StorageRepository {
  final CacheLocalDataSource localDataSource;
  final StorageRemoteDataSource remoteDataSource;

  Future<Either<StorageFailure, String>> getDownloadUrl({
    required String path,
    required DateTime? invalidateCacheBefore,
    required Duration? invalidateCacheDuration,
  }) => forwardedCachedGet<StorageFailure, String>(
    path: path,
    key: const UrlCacheKey(),         // SharedPreferences key prefix: 'url'
    getFromRemote: remoteDataSource.getDownloadUrl,
    getFromLocal: localDataSource.getDownloadUrl,
    setLocal: localDataSource.setDownloadUrl,
    setSavedAtLocal: localDataSource.setSavedAt,
    emptyCacheFailure: const EmptyCacheStorageFailure(),
    unidentifiedFailure: const UnidentifiedStorageFailure(),
    localDataSource: localDataSource,
    ...
  );

  Future<Either<StorageFailure, dynamic>> getJson({...}) => forwardedCachedGet<...>(
    key: const JsonCacheKey(),         // SharedPreferences key prefix: 'json'
    ...
  );
}