SETUP.md

Basic Setup

In order to perform API request, you must implement the protocol Dispatcher. You are welcome to create your own implementations, but we provide one we believe will suffice common needs. By providing objects for our Environment class and a few protocols, you may initialize the CommonMoyaDispatcher. In the following sections, we will explore the dependencies of this class.

open class CommonMoyaDispatcher: MoyaDispatcher {

    public var environment: Environment
    public let resultHandler: ResultHandler
    public let errorFilter: ErrorFilter
    public let interceptor: RequestInterceptor

//...

For information on the RequestInterceptor, please consult Alamofire.

Environment

public class Environment {

    public let baseURL: URL?

    public let type: EnvironmentSpecifying // protocol used to define the environment (development, production, store..)

    public let name: String

    public var commonHeaders: Headers

    public let cachePolicy: URLRequest.CachePolicy

    public let fixturesType: FixtureTypeSpecifying // protocol to define how data is simulated

    public var specificHeaders: SpecificHeaders // protocol to define headers to a specific group of endpoints

    public var serverTrustManager: ServerTrustManager

// ...

The goal of this class is to be used to distinguish the environment in which the request is being performed. Its attributes will be used to modify requests and how responses are dealt with. There are multiple convenience inits to help initialize this class.

It is also in the Environment where you can easily set up certificate pinning. By either providing a direct implementation of the class ServerTrustManager or an implementation of the protocol Certificate (recommended), the pinning will be enabled.

ResultHandler

By conforming to this protocol, you can intercept the result before it is returned to its caller (dispatcher methods that map the response). By doing this you will be able to handle results in specific ways. For instance you may navigate to a specific screen when the session expires or a breach is detected.

public class TFResultHandler: ResultHandler {

    internal weak var coordinator: SignOutSceneCoordinating?

    public init(coordinator: SignOutSceneCoordinating?) {
        self.coordinator = coordinator
    }

    public func handleRequest(response: Response?, completion: @escaping GenericCompletion<Void>) {
        completion(.success(()))
    }

    public func handleRequest(error: Error?, completion: @escaping GenericCompletion<Void>) {
        guard let interactionError = error as? InteractionError else {
            completion(.success(()))
            return
        }
        switch interactionError {
        case .expiredUserSession:
            handleExpiredUserSession()
            completion(.success(()))
        default:
            completion(.success(()))
        }
    }

    private func handleExpiredUserSession() {
        coordinator?.didSignOut()
    }
}

ErrorFilter

Objects conforming to this protocol will allow detecting errors in response initially assumed as successful, as well mapping/translating the returning errors in custom errors implemented in your application.

public func filterForErrors(in result: MoyaDispatcherResult) -> MoyaResult {
    let localizedMessages = (result as? MyMoyaDispatcherResult)?.localizedMessages
    let moyaError = result.result.failure
    let underlyingResponse = result.result.success ?? moyaError?.response
    do {
        guard let response = underlyingResponse else {
            let error = (moyaError?.underlyingError ?? moyaError) ?? getDefaultError()
            return .failure(MoyaError.underlying(error.filter(), underlyingResponse))
        }
        let moyaDispatcherResponse = MyMoyaDispatcherResponse(moyaResponse: response,
                                                              localizedMessages: localizedMessages!)
        return .success(try filterForErrors(in: moyaDispatcherResponse))
    } catch {
        return .failure(MoyaError.underlying(error, underlyingResponse))
    }
}