networking-layer

# Networking Layer Generator Generate a modern, protocol-based networking layer using Swift's async/await concurrency, with proper error handling and easy testability. ## When This Skill Activates Use this skill when the user: - Asks to "add networking" or "create API client" - Mentions "HTTP layer" or "REST API" - Wants to "fetch data from API" - Asks about "URLSession wrapper" or "network requests" ## Pre-Generation Checks ### 1. Project Context Detection - [ ] Check Swift version (async/await requires Swift 5.5+) - [ ] Check deployment target (async/await requires iOS 15+ / macOS 12+) - [ ] Search for existing networking implementations - [ ] Identify source file locations ### 2. Conflict Detection Search for existing networking: ``` Glob: **/*API*.swift, **/*Network*.swift, **/*Client*.swift Grep: "URLSession" or "HTTPURLResponse" ``` If found, ask user: - Replace existing implementation? - Extend with new endpoints? ## Configuration Questions Ask user via AskUserQuestion: 1. **Authentication type?** - Bearer token - API key (header or query param) - None - Custom 2. **Base URL configuration?** - Single environment - Multiple environments (dev/staging/prod) 3. **Additional features?** - Retry logic with exponential backoff - Request/response logging - Caching ## Generation Process ### Step 1: Create Core Files Generate these files: 1. `APIClient.swift` - Protocol and implementation 2. `APIEndpoint.swift` - Endpoint definition protocol 3. `NetworkError.swift` - Typed errors 4. `APIConfiguration.swift` - Base URL and auth config ### Step 2: Optional Files Based on configuration: - `RetryPolicy.swift` - If retry logic selected - `NetworkLogger.swift` - If logging selected ### Step 3: Determine File Location Check project structure: - If `Sources/` exists → `Sources/Networking/` - If `App/` exists → `App/Networking/` - Otherwise → `Networking/` ## Swift 6.2 Concurrency Notes Reference: Apple's Swift Concurrency Updates ### @concurrent for Background Work Use `@concurrent` to offload heavy processing: ```swift @concurrent static func parseResponse<T: Decodable>(_ data: Data) async throws -> T { try JSONDecoder().decode(T.self, from: data) } ``` ### MainActor for UI Updates Keep UI-related code on MainActor: ```swift @Observable @MainActor final class NetworkViewModel { var items: [Item] = [] func fetch() async { items = try await apiClient.fetch(ItemsEndpoint()) } } ``` ## Output Format After generation, provide: ### Files Created ``` Sources/Networking/ ├── APIClient.swift # Protocol + URLSession implementation ├── APIEndpoint.swift # Endpoint protocol ├── NetworkError.swift # Error types ├── APIConfiguration.swift # Config (base URL, auth) └── Endpoints/ # Example endpoints └── ExampleEndpoint.swift ``` ### Integration Steps **Define an Endpoint:** ```swift struct UsersEndpoint: APIEndpoint { typealias Response = [User] var path: String { "/users" } var method: HTTPMethod { .get } } ``` **Make a Request:** ```swift let client = URLSessionAPIClient(configuration: .production) let users = try await client.request(UsersEndpoint()) ``` **With SwiftUI:** ```swift struct UsersView: View { @State private var users: [User] = [] @Environment(\.apiClient) private var apiClient var body: some View { List(users) { user in Text(user.name) } .task { users = try await apiClient.request(UsersEndpoint()) } } } ``` ### Testing Use `MockAPIClient` for tests: ```swift let mockClient = MockAPIClient() mockClient.mockResponse(for: UsersEndpoint.self, response: [User.mock]) let viewModel = UsersViewModel(apiClient: mockClient) await viewModel.fetch() XCTAssertEqual(viewModel.users.count, 1) ``` ## References - **networking-patterns.md** - Architecture patterns and best practices - **templates/** - All template files - Apple Docs: Swift Concurrency Updates (Swift 6.2)