Matt Bruce 4228fbc849 Update Models, Services + docs

Summary:
- Sources: Models, Services
- Docs: Proposal, README
- Added symbols: extension StorageKeys, struct UserTokenKey, typealias Value, enum KeychainAccessControl, enum KeychainAccessibility, actor EncryptionHelper (+38 more)
- Removed symbols: enum KeychainAccessControl, enum KeychainAccessibility, enum EncryptionConstants, func serialize, func deserialize, func applySecurity (+17 more)

Stats:
- 10 files changed, 1089 insertions(+), 348 deletions(-)

2026-01-18 14:53:25 -06:00

2.6 KiB

Raw Blame History

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)

Architecture

Core Components

StorageKey protocol - Defines storage configuration for each data type
StorageRouter actor - Main entry point coordinating all storage operations
StorageProviding protocol - Abstraction for storage operations

Isolated Helper Classes (Actors)

Each helper is a dedicated actor providing thread-safe access to a specific storage domain:

KeychainHelper - All keychain operations (set, get, delete, exists, deleteAll)
EncryptionHelper - AES-256-GCM encryption with PBKDF2 key derivation
FileStorageHelper - File system operations (read, write, delete, list, size)
UserDefaultsHelper - UserDefaults operations with suite support
SyncHelper - WatchConnectivity sync operations

Models

StorageDomain - userDefaults, keychain, fileSystem, encryptedFileSystem
SecurityPolicy - none, keychain (with accessibility/accessControl), encrypted (AES-256)
Serializer - JSON, property list, raw Data, or custom encode/decode
PlatformAvailability - all, phoneOnly, watchOnly, phoneWithWatchSync
SyncPolicy - never, manual, automaticSmall
KeychainAccessibility - All 7 iOS options (whenUnlocked, afterFirstUnlock, etc.)
KeychainAccessControl - All 6 options (userPresence, biometryAny, devicePasscode, etc.)
FileDirectory - documents, caches, custom URL
StorageError - Comprehensive error types
AnyCodable - Type-erased Codable for 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.

Platforms

iOS 17+
watchOS 10+

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.

2.6 KiB Raw Blame History