Cache

Cache is a Swift library for caching Identifiable values with optional expiry logic. It supports both in-memory and file-backed storage, making it suitable for short-lived data, offline persistence, or resource caching.

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Features

• ✅ Type-safe caching for any Identifiable type
• 📦 Two interchangeable storage implementations:
  • VolatileCache: fast in-memory storage
  • FileSystemCache: persistent, file-backed storage
• ⏱ Expiry support: .short or .custom(Date)
• 🧪 Testable without delays (no need for sleep)
• 🕹 Native async/await support. Fully thread safe and sendable.
• 🧩 Easily injectable via swift-dependencies

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Usage

Volatile (in-memory) caching

let cache = VolatileCache<MyModel>()

try await cache.stash(MyModel(id: "a", name: "Temp"), duration: .short)

let item = try await cache.resource(for: "a")

File-backed persistent caching

let cache = try FileSystemCache<MyModel>(directory: .caches, "games")

try await cache.stash(MyModel(id: "b", name: "something"), duration: .custom(.distantFuture))

let item = try await cache.resource(for: "b")

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Dependency Injection

If you're using swift-dependencies, you can expose your preferred cache type as a dependency:

import Dependencies
import Cache

extension DependencyValues {
    /// A cache for storing and retrieving `Sport` models.
    var sportCache: any Cache<Sport> {
        get { self[SportCacheKey.self] }
        set { self[SportCacheKey.self] = newValue }
    }
}

private enum SportCacheKey: DependencyKey {
    static let liveValue: any Cache<Sport> = FileSystemCache(
        directory: .caches,
        subfolder: "sports"
    )
}

Then use it like this:

@Dependency(\.sportCache) var sportCache
let sport = try await sportCache.resource(for: id)