URLSessionAdapter

A Codable wrapper around URLSession for networking. Includes both APIs: async/await and callbacks.

Supports data, upload, and download URL session tasks.

Installation

Swift Package Manager

To install URLSessionAdapter using Swift Package Manager:

Xcode: File -> Add Packages
Enter Package URL: https://github.com/denissimon/URLSessionAdapter

CocoaPods

To install URLSessionAdapter using CocoaPods, add this line to your Podfile:

pod 'URLSessionAdapter', '~> 1.6'

Carthage

To install URLSessionAdapter using Carthage, add this line to your Cartfile:

github "denissimon/URLSessionAdapter"

Manually

Copy folder URLSessionAdapter into your project.

Usage

Defining a Codable instance:

struct Activity: Codable {
    let id: Int?
    let name: String
    let description: String
}

Defining API endpoints:

import URLSessionAdapter

struct APIEndpoints {
    
    static let baseURL = "https://api.example.com/rest"
    static let apiKey = "api_key"
    
    static func getActivity(id: Int) -> EndpointType {
        let path = "/activities/\(id)/?api_key=\(APIEndpoints.apiKey)"        
        return Endpoint(
            method: .GET,
            baseURL: APIEndpoints.baseURL,
            path: path,
            params: nil)
    }
    
    static func createActivity(_ activity: Activity) -> EndpointType {
        let path = "/activities/?api_key=\(APIEndpoints.apiKey)"
        
        let activityData = activity.encode()
        let params = HTTPParams(httpBody: activityData, headerValues:[
        (value: "application/json", forHTTPHeaderField: "Content-Type")])
        
        return Endpoint(
            method: .POST,
            baseURL: APIEndpoints.baseURL,
            path: path,
            params: params)
    }
}

Defining API methods:

import URLSessionAdapter

class ActivityRepository {
    
    let networkService: NetworkServiceType
    
    init(networkService: NetworkServiceType) {
        self.networkService = networkService
    }
    
    func getActivity(id: Int) async -> Result<Activity, CustomError>
        let endpoint = APIEndpoints.getActivity(id: id)
        guard let request = RequestFactory.request(endpoint) else { return .failure(customError()) }
        do {
            let activity = try await networkService.request(request, type: Activity.self)
            return .success(activity)
        } catch {
            return .failure(error as! CustomError)
        }
    }
    
    func createActivity(_ activity: Activity) async -> Result<Data?, CustomError> {
        let endpoint = APIEndpoints.createActivity(activity)
        guard let request = RequestFactory.request(endpoint) else { return .failure(customError()) }
        do {
            let data = try await networkService.request(request)
            return .success(data)
        } catch {
            return .failure(error as! CustomError)
        }
    }
}

API calls:

let networkService = NetworkService(urlSession: URLSession.shared)
let activityRepository = ActivityRepository(networkService: networkService)

Task {
    let result = await activityRepository.getActivity(id: 1)
    switch result {
    case .success(let activity):
        ...
    case .failure(let error):
        ...
    }
}

Task {
    // The server returns the id of the created activity
    let result = await activityRepository.createActivity(activity)
    switch result {
    case .success(let data):
        guard let data = data, 
              let createdActivityId = Int(String(data: data, encoding: .utf8) ?? "") else {
            ...
        }
        ...
    case .failure(let error):
        ...
    }
}

// To fetch a file:
let data = try await networkService.fetchFile(url: url)
guard let image = UIImage(data: data) else {
    ...
}

// To download a file:
guard try await networkService.downloadFile(url: url, to: localUrl) else {
    ...
}

// To upload a file:
let endpoint = JSONPlaceholderAPI.uploadFile(file)
guard let request = RequestFactory.request(endpoint) else { return }
let config = RequestConfig(uploadTask: true)
let response = try await networkService.request(request, config: config)

// To get a result with status code:
let endpoint = JSONPlaceholderAPI.createPost(post)
guard let request = RequestFactory.request(endpoint) else { return }
let response = try await networkService.requestWithStatusCode(request, type: Post.self)
let post = response.result // Returned created Post
let statusCode = response.statusCode // Returned 201 status code

Validation:

// By default, any 400-599 status code returned by the server throws a NetworkError:
do {
    // The server will return status code 404
    let response = try await networkService.requestWithStatusCode(request)
    ...
} catch {
    if error is NetworkError {
        let networkError = error as! NetworkError
        let errorDescription = networkError.error?.localizedDescription
        let errorStatusCode = networkError.statusCode // 404
        let errorDataStr = String(data: networkError.data ?? Data(), encoding: .utf8)!
        ...
    } else {
        // Handling other errors
        ...
    }
}

// Optionally, this automatic validation can be disabled globally:
networkService.autoValidation = false
do {
    // The server will return status code 404
    let response = try await networkService.requestWithStatusCode(request)
    let statusCode = response.statusCode // 404
    let resultStr = String(data: response.result ?? Data(), encoding: .utf8)!
} catch {
    ...
}

// Or this automatic validation can be disabled for a given request:
do {
    // The server will return status code 404
    let config = RequestConfig(autoValidation: false)
    let response = try await networkService.requestWithStatusCode(request, config: config)
    let statusCode = response.statusCode // 404
    let resultStr = String(data: response.result ?? Data(), encoding: .utf8)!
} catch {
    ...
}

More usage examples can be found in tests and iOS-MVVM-Clean-Architecture where this adapter was used.

Public methods

// async/await API

func request(_ request: URLRequest, config: RequestConfig?) async throws -> Data
func request<T: Decodable>(_ request: URLRequest, type: T.Type, config: RequestConfig?) async throws -> T
func fetchFile(url: URL, config: RequestConfig?) async throws -> Data?
func downloadFile(url: URL, to localUrl: URL, config: RequestConfig?) async throws -> Bool

func requestWithStatusCode(_ request: URLRequest, config: RequestConfig?) async throws -> (result: Data, statusCode: Int?)
func requestWithStatusCode<T: Decodable>(_ request: URLRequest, type: T.Type, config: RequestConfig?) async throws -> (result: T, statusCode: Int?)
func fetchFileWithStatusCode(url: URL, config: RequestConfig?) async throws -> (result: Data?, statusCode: Int?)
func downloadFileWithStatusCode(url: URL, to localUrl: URL, config: RequestConfig?) async throws -> (result: Bool, statusCode: Int?)

// callbacks API

func request(_ request: URLRequest, config: RequestConfig?, completion: @escaping (Result<Data?, NetworkError>) -> Void) -> NetworkCancellable?
func request<T: Decodable>(_ request: URLRequest, type: T.Type, config: RequestConfig?, completion: @escaping (Result<T, NetworkError>) -> Void) -> NetworkCancellable?
func fetchFile(url: URL, config: RequestConfig?, completion: @escaping (Result<Data?, NetworkError>) -> Void) -> NetworkCancellable?
func downloadFile(url: URL, to localUrl: URL, config: RequestConfig?, completion: @escaping (Result<Bool, NetworkError>) -> Void) -> NetworkCancellable?

func requestWithStatusCode(_ request: URLRequest, config: RequestConfig?, completion: @escaping (Result<(result: Data?, statusCode: Int?), NetworkError>) -> Void) -> NetworkCancellable?
func requestWithStatusCode<T: Decodable>(_ request: URLRequest, type: T.Type, config: RequestConfig?, completion: @escaping (Result<(result: T, statusCode: Int?), NetworkError>) -> Void) -> NetworkCancellable?
func fetchFileWithStatusCode(url: URL, config: RequestConfig?, completion: @escaping (Result<(result: Data?, statusCode: Int?), NetworkError>) -> Void) -> NetworkCancellable?
func downloadFileWithStatusCode(url: URL, to localUrl: URL, config: RequestConfig?, completion: @escaping (Result<(result: Bool, statusCode: Int?), NetworkError>) -> Void) -> NetworkCancellable?

Requirements

iOS 15.0+, macOS 12.0+, tvOS 15.0+, watchOS 8.0+

License

Licensed under the MIT license