<div id="readability-page-1" class="page"><div>실제 production app 을 개발하다 보면 <code>AppDelegate</code> 클래스가 쉽게 비대해지고 파일수가 어마어마하게 늘어나는 경우가 비일비재하다. 이를 refactoring 하는 방법<h3 id="mediator-design-pattern">Mediator Design Pattern</h3><a href="https://www.vadimbulavin.com/refactoring-massive-app-delegate/">refactoring-massive-app-delegate</a> 에 보면 다양한 디자인 패턴으로 appDelegate를 refactoring 하는 법이 나와있다 그중 mediator design pattern 으로 실제 활용한 예<h3 id="applifecycle-mediator">AppLifecycle Mediator</h3><ul><li>먼저 AppLifeCycle mediator 를 정의한다.</li><li>아래 소스는 <code>appDelegate.m</code> 이 objective-c 로 구현되어 있기에 <code>NSObject</code>를 상속받고 <code>objc</code> propertyObserver를 붙였다.</li></ul><pre data-lang="swift"><code data-lang="swift">import Foundation

// MARK: - AppLifecycleListener
protocol AppLifecycleListener {
 func onAppWillEnterForeground()
 func onAppDidEnterBackground()
 func onAppDidFinishLaunching()
}

extension AppLifecycleListener {
 func onAppWillEnterForeground() {}
 func onAppDidEnterBackground() {}
}

// MARK: - Mediator
@objc
class AppLifecycleMediator: NSObject {
 private let listeners: [AppLifecycleListener]
 
 init(listeners: [AppLifecycleListener]) {
 self.listeners = listeners
 super.init()
 subscribe()
 }
 
 deinit {
 NotificationCenter.default.removeObserver(self)
 }
 
 private func subscribe() {
 NotificationCenter.default.addObserver(self, selector: #selector(onAppWillEnterForeground), name: UIApplication.willEnterForegroundNotification, object: nil)
 NotificationCenter.default.addObserver(self, selector: #selector(onAppDidEnterBackground), name: UIApplication.didEnterBackgroundNotification, object: nil)
 NotificationCenter.default.addObserver(self, selector: #selector(onAppDidFinishLaunching), name: UIApplication.didFinishLaunchingNotification, object: nil)
 }
 
 @objc private func onAppWillEnterForeground() {
 listeners.forEach { $0.onAppWillEnterForeground() }
 }
 
 @objc private func onAppDidEnterBackground() {
 listeners.forEach { $0.onAppDidEnterBackground() }
 }
 
 @objc private func onAppDidFinishLaunching() {
 listeners.forEach { $0.onAppDidFinishLaunching() }
 }
}
</code></pre><h3 id="applistener-class-guhyeon">AppListener class 구현</h3><ul><li>이제 <code>AppLifecycleListener</code> 를 상속하여 클래스를 구현한다.</li><li>appDelegate 에서 구현된 각각의 서비스 구현들을 여기에 Extract 하여 구현</li><li>예를 들면 기존에 AppDelegate에서 구현되어있던 location permission 관련 feature 들은 아래와 같이 <code>AppLocationListener</code> 구현한다.</li></ul><pre data-lang="swift"><code data-lang="swift">import Foundation
import CoreLocation
import LoggingKit

class AppLocationListener: NSObject, AppLifecycleListener {
 let locationManager = CLLocationManager()
 
 fileprivate func permissionState(_ status: CLAuthorizationStatus) {
 LogService.shared.debug("LocationPermission: \(status.rawValue)", logCategory: \.debug)
 switch status {
 case .authorizedAlways, .authorizedWhenInUse:
 locationManager.startUpdatingLocation()
 case .restricted, .notDetermined:
 locationManager.requestWhenInUseAuthorization()
 case .denied:
 stopLocation()
 @unknown default:
 print("GPS: Default")
 }
 }
 
 func stopLocation() {
 locationManager.stopUpdatingHeading()
 locationManager.stopUpdatingLocation()
 locationManager.delegate = nil
 }
 
 func onAppDidFinishLaunching() {
 locationManager.delegate = self
 locationManager.desiredAccuracy = kCLLocationAccuracyBest
 let status: CLAuthorizationStatus
 if #available(iOS 14.0, *) {
 status = locationManager.authorizationStatus
 } else {
 status = CLLocationManager.authorizationStatus()
 }
 permissionState(status)
 }
}

extension AppLocationListener: CLLocationManagerDelegate {
 func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
 self.permissionState(status)
 }
 
 func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
 locationManager.stopUpdatingLocation()
 }
 
 func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
 let newLocation = locations[0]
 let geocoder = CLGeocoder()
 geocoder.reverseGeocodeLocation(newLocation) { (playmarks, error) in
 if let _ = error {
 self.stopLocation()
 return
 }
 
 if let city = playmarks?.first?.locality {
 cityDefault.saveLocationLng("\(newLocation.coordinate.longitude)")
 cityDefault.saveLocationLat("\(newLocation.coordinate.latitude)")
 cityDefault.saveLocationCity(city)
 }
 }
 stopLocation()
 }
}

</code></pre><ul><li>그리고 <code>AppLifecycleMediator</code> 에 listener 에 추가</li></ul><pre data-lang="swift"><code data-lang="swift">extension AppLifecycleMediator {
 @objc
 static func makeDefaultMediator() -&gt; AppLifecycleMediator {
 let locationListener = AppLocationListener()
 let debugListener = AppDebugListener()

 return AppLifecycleMediator(listeners: [debugListener, locationListener])
 }
}

</code></pre><ul><li>3rdParty service 들, debug feature 등 listener 로 추가하여 refactoring 해주면 된다.</li></ul><h3 id="add-mediator-to-appdelegate">add mediator to AppDelegate</h3><ul><li>이제 mediator class 를 AppDelegate 에 등록한다.</li><li>다음 코드 한줄만 appDelegate 에 추가하면 된다.</li></ul><pre data-lang="swift"><code data-lang="swift">@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate {

 var window: UIWindow?

 let mediator = AppLifecycleMediator.makeDefaultMediator() // 여기에 추가

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -&gt; Bool {

 return true

 }
}
</code></pre><ul><li>objective-c 구현에 붙인다면 조금 애매한데 <code>willFinishLaunchingWithOptions</code> 메소드에 다음과 같이 추가하였다.</li></ul><pre data-lang="objc"><code data-lang="objc">@interface AppDelegate ()&lt;CLLocationManagerDelegate, UNUserNotificationCenterDelegate, FIRMessagingDelegate, AppsFlyerLibDelegate&gt;
{
 AppLifecycleMediator *_mediator; // 여기에 선언하고 
}


...
- (BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 _mediator = [AppLifecycleMediator makeDefaultMediator]; // 구현추가.
 return YES;
}

</code></pre><h2 id="reference">Reference</h2><ul><li><a href="https://www.vadimbulavin.com/refactoring-massive-app-delegate/">refactoring-massive-app-delegate</a></li><li><a href="https://andreaslydemann.com/architecting-an-analytics-service-for-ios-apps/">Architecting an Analytics Service for iOS Apps – Andreas Lüdemann (andreaslydemann.com)</a></li></ul></div></div>

kwanghyun won

Refactoring Massive App Delegate#
실제 production app 을 개발하다 보면 AppDelegate 클래스가 쉽게 비대해지고 파일수가 어마어마하게 늘어나는 경우가 비일비재하다. 이를 refactoring 하는 방법

Refactoring Massive App Delegate

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