Networking layer abstraction
Add this to Cartfile:
git "https://github.com/bocato/Networking.git" ~> 1.0
Then:
$ carthage update
- Use as an abstraction and implement your own dispatcher or use the provided
URLSessionDispatcher.
enum PokemonsRequest: Request {
case list(limit: Int?)
var path: String {
switch self {
case .list:
return "pokemon"
}
}
var method: HTTPMethod {
switch self {
case .list:
return .get
}
}
var headers: [String : String]? {
return nil
}
var parameters: RequestParameters? {
switch self {
case let .list(limit):
guard let limit = limit else { return nil }
return .url(["limit": limit])
}
}
}final class PokemonsDataService: NetworkingService {
// MARK: - Properties
var dispatcher: URLRequestDispatching
// MARK: - Initialization
init(dispatcher: URLRequestDispatching) {
self.dispatcher = dispatcher
}
// MARK: - Requests
func getList(completion: @escaping (Result<Data, Error>) -> Void) {
let request: PokemonsRequest = .list
dispatcher.execute(request: request) { (result) in
switch result {
case let .failure(error):
completion(.failure(error))
case .success(data):
guard let data = data else {
completion(.failure(NSError()))
return
}
completion(data)
}
}
}
}final class PokemonsDataService: CodableRequesting {
// MARK: - Properties
var dispatcher: URLRequestDispatching
// MARK: - Initialization
init(dispatcher: URLRequestDispatching) {
self.dispatcher = dispatcher
}
// MARK: - Requests
func getList(completion: @escaping (Result<[Pokemon], NetworkingError>) -> Void) {
let request: PokemonsRequest = .list
requestCodable(request, ofType: [Pokemon].self) { (networkingResult) in
switch networkingResult {
case let .failure(error):
completion(.failure(error))
case .success(data):
guard let data = data else {
completion(.failure(.noData))
return
}
completion(data)
}
}
}
}The URLRequestAdapter protocol allows each request that conforms with URLRequestProtocol request made on a URLRequestDispatcher to be inspected and adapted before being created.
One very specific way to use an adapter is to append an Authorization header to requests behind a certain type of authentication.
final class AccessTokenAdapter: URLRequestAdapter {
private let accessToken: String
init(accessToken: String) {
self.accessToken = accessToken
}
func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
var urlRequest = urlRequest
if let urlString = urlRequest.url?.absoluteString, urlString.hasPrefix("https://httpbin.org") {
urlRequest.setValue("Bearer " + accessToken, forHTTPHeaderField: "Authorization")
}
return urlRequest
}
}The request will be like this:
enum PokemonsRequest: Request {
case list(limit: Int?, accessToken: String)
var path: String {
switch self {
case .list:
return "pokemon"
}
}
var method: HTTPMethod {
switch self {
case .list:
return .get
}
}
var headers: [String : String]? {
return nil
}
var parameters: RequestParameters? {
switch self {
case let .list(limit):
guard let limit = limit else { return nil }
return .url(["limit": limit])
}
}
var adapters: [URLRequestAdapters]? {
switch self {
case let .list(_, accessToken):
return [AccessTokenAdapter(accessToken: accessToken)]
}
}
}