 Sign in with Apple + Rx

ASAuthorizationControllerProxy.swift

import AuthenticationServices
import RxCocoa
import RxSwift
import UIKit

@available(iOS 13.0, *)
extension ASAuthorizationController: HasDelegate {
    public typealias Delegate = ASAuthorizationControllerDelegate
}

@available(iOS 13.0, *)
class ASAuthorizationControllerProxy: DelegateProxy<ASAuthorizationController, ASAuthorizationControllerDelegate>, DelegateProxyType, ASAuthorizationControllerDelegate, ASAuthorizationControllerPresentationContextProviding {
    var presentationWindow: UIWindow = UIWindow()

    public init(controller: ASAuthorizationController) {
        super.init(parentObject: controller, delegateProxy: ASAuthorizationControllerProxy.self)
    }

    // MARK: - DelegateProxyType

    public static func registerKnownImplementations() {
        register { ASAuthorizationControllerProxy(controller: $0) }
    }

    // MARK: - Proxy Subject

    internal lazy var didComplete = PublishSubject<ASAuthorization>()

    // MARK: - ASAuthorizationControllerDelegate

    func authorizationController(controller: ASAuthorizationController, didCompleteWithAuthorization authorization: ASAuthorization) {
        didComplete.onNext(authorization)
        didComplete.onCompleted()
    }

    func authorizationController(controller: ASAuthorizationController, didCompleteWithError error: Error) {
        didComplete.onCompleted()
    }

    // MARK: - ASAuthorizationControllerPresentationContextProviding

    func presentationAnchor(for controller: ASAuthorizationController) -> ASPresentationAnchor {
        return presentationWindow
    }

    // MARK: - Completed

    deinit {
        self.didComplete.onCompleted()
    }
}

AuthenticationServices+Rx.swift

import AuthenticationServices
import RxCocoa
import RxSwift
import UIKit

@available(iOS 13.0, *)
extension Reactive where Base: ASAuthorizationAppleIDProvider {
    public func login(scope: [ASAuthorization.Scope]? = nil, on window: UIWindow) -> Observable<ASAuthorization> {
        let request = base.createRequest()
        request.requestedScopes = scope

        let controller = ASAuthorizationController(authorizationRequests: [request])

        let proxy = ASAuthorizationControllerProxy.proxy(for: controller)
        proxy.presentationWindow = window

        controller.presentationContextProvider = proxy
        controller.performRequests()

        return proxy.didComplete
    }
}

@available(iOS 13.0, *)
extension Reactive where Base: ASAuthorizationAppleIDButton {
    public func loginOnTap(scope: [ASAuthorization.Scope]? = nil) -> Observable<ASAuthorization> {
        let window = base.window!
        return controlEvent(.touchUpInside)
            .flatMap {
                ASAuthorizationAppleIDProvider().rx.login(scope: scope, on: window)
            }
    }

    public func login(scope: [ASAuthorization.Scope]? = nil) -> Observable<ASAuthorization> {
        return ASAuthorizationAppleIDProvider().rx.login(scope: scope, on: base.window!)
    }
}

ViewController.swift

import AuthenticationServices

let appleLoginButton = ASAuthorizationAppleIDButton()

//...

appleLoginButton.rx
    .loginOnTap(scope: [.fullName, .email])
    .subscribe(onNext: { result in
        guard let auth = result.credential as? ASAuthorizationAppleIDCredential else { return }
        print(auth.user)
        print(auth.email)
        print(auth.fullName?.givenName)
        print(auth.fullName?.familyName)
    })
    .disposed(by: disposeBag)

안녕하세요! 이 코드를 사용하려고하는데 'AuthenticationServices+Rx.swift'파일 27번째줄(let window = base.window!)이부분에 <Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value> 이 에러가 뜨네요.. 해결방법이 있을까요?

appleLoginButton.rx
.loginOnTap(scope: [.fullName, .email])
.subscribe(onNext: { result in
guard let auth = result.credential as? ASAuthorizationAppleIDCredential else { return }
print(auth.user)
print(auth.email)
print(auth.fullName?.givenName)
print(auth.fullName?.familyName)
})
.disposed(by: disposeBag)
를 viewDidAppear 에서 구현 하세요

window가 없다는 것은 버튼이 뷰에 붙지 않았다는 거니까. 붙은 이후에 호출하시면 됩니다.
강제 unwrapping 한 이유는 죽어야 잘못된걸 알 수 있으니까 죽으라고 그런겁니다.