LocalData Package Proposal

Goal

Create a single, typed, discoverable namespace for persisted app data with consistent security guarantees and clear ownership. This makes it obvious what is stored, where it is stored, how it is secured, how it is serialized, who owns it, and which platforms it belongs to or should sync to.

Package Placement

localPackages/LocalData/
- Sources/LocalData/
- Tests/LocalDataTests/

Dependencies

Foundation
Security (Keychain)
CryptoKit (encryption)
WatchConnectivity (sync helpers)

Implemented Scope

StorageKey protocol and StorageKeys namespace for app-defined keys
StorageRouter actor with async set, get, and remove
StorageDomain options for user defaults, keychain, file system, and encrypted file system
SecurityPolicy options for none, keychain, and encrypted data
Serializer for JSON, property lists, raw Data, or custom encode and decode
PlatformAvailability and SyncPolicy metadata
AnyCodable for simple mixed-type payloads

Usage Pattern

Apps extend StorageKeys with their own key types and use StorageRouter.shared. This follows the Notification.Name pattern for discoverable keys.

Sync Behavior

StorageRouter can call WCSession.updateApplicationContext for manual or automaticSmall sync policies when availability allows it. Session activation and receiving data are owned by the app.

Future Ideas (Not Implemented)

Migration helpers for legacy storage
Key rotation strategies for encrypted data
Watch-optimized data representations

Any future changes should keep LocalData documentation in sync with code changes.

1.6 KiB Raw Blame History