swift-actor-persistence

Thread-safe Swift data persistence is achieved by using an actor-based repository that serializes access to shared data. This approach combines an in-memory cache with durable file-backed storage to prevent data races during concurrent read and write operations.

Using Swift actors for offline-first iOS apps prevents data races by serializing access to shared data. An actor-based repository synchronizes an in-memory cache with file-backed storage, ensuring safe concurrent data access without explicit locks.

To set up a local repository, define your Swift models conforming to Codable and Identifiable. Then, create a generic LocalRepository instance and use async calls to save, delete, and fetch items with atomic file writes.

Yes, this actor-based persistence works on macOS and requires Swift 5.5 or later. It applies to iOS and macOS apps needing safe concurrent access to shared data using the actor model with Codable and Identifiable types.

Atomic file writes ensure durability by writing data to a temporary file first, then replacing the original file only after success. This prevents data corruption during concurrent access or unexpected system failures in your Swift app.