fmo91 / pluggableapplicationdelegate

Smallest AppDelegate ever by using a decoupled-services based architecture. 🛠

PluggableApplicationDelegate

Introduction

AppDelegate is a traditional example of bad code. Lots of line of code that makes so much different things are put together in methods that are called within the application life cycle. But all of those concerns are over. Using PluggableApplicationDelegate you decouple AppDelegate from the services that you plug to it. Each ApplicationService has its own life cycle that is shared with AppDelegate.

At a glance

Let see some code. Here is how a ApplicationService is like:

import Foundation
import PluggableApplicationDelegate

final class LoggerApplicationService: NSObject, ApplicationService {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
        
        print("It has started!")
        
        return true
    }
    
    func applicationDidEnterBackground(_ application: UIApplication) {
        print("It has entered background")
    }
}

That's all. It is exactly the same as a AppDelegate. Think of ApplicationService as sub-AppDelegates.

In AppDelegate you just have to inherit from PluggableApplicationDelegate to register the services.

import UIKit
import PluggableApplicationDelegate

@UIApplicationMain
class AppDelegate: PluggableApplicationDelegate {
    
    override var services: [ApplicationService] {
        return [
            LoggerApplicationService()
        ]
    }
}

Yes. That's all. Simple.

How does this work?

You may want to read my Medium post about Pluggable App Delegate. Basically, you do an inversion of control. Instead of let AppDelegate instantiate your dependencies, perform actions at every step of its life cycle, you create objects that share the AppDelegate life cycle and plug them into your AppDelegate. Those objects are observers of the AppDelegate. Your AppDelegate has the only responsibility of notify them about its life cycle events.

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

PluggableApplicationDelegate requires Swift 3.0 or above.

Installation

PluggableApplicationDelegate is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'PluggableApplicationDelegate'

Author

fmo91, [email protected]

License

PluggableApplicationDelegate is available under the MIT license. See the LICENSE file for more info.

pluggableapplicationdelegate's Issues

Variable 'result' was written to, but never read

From version 0.1.2:

    @available(iOS 3.0, *)
    public func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
        var result = true
        
        for service in __services {
            if let serviceResult = service.application?(application, didFinishLaunchingWithOptions: launchOptions) {
                if serviceResult == false {
                    result = false
                }
            }
        }
        
        return true
    }
    @available(iOS, introduced: 2.0, deprecated: 9.0, message: "Please use application:openURL:options:")
    public func application(_ application: UIApplication, handleOpen url: URL) -> Bool {
        var result = true
        
        for service in __services {
            if service.application?(application, handleOpen: url) == false {
                result = false
            }
        }
        
        return true
    }
    
    @available(iOS, introduced: 4.2, deprecated: 9.0, message: "Please use application:openURL:options:")
    public func application(_ application: UIApplication, open url: URL, sourceApplication: String?, annotation: Any) -> Bool {
        var result = true
        
        for service in __services {
            if service.application?(application, open: url, sourceApplication: sourceApplication, annotation: annotation) == false {
                result = false
            }
        }
        
        return true
    }

result variable can be removed. These methods could just return false from within the for/if blocks.

Warnings in debug log

Great idea, really helps with organisation. I am seeing these warnings pop up in the debug log, however:

You've implemented -[<UIApplicationDelegate> application:performFetchWithCompletionHandler:], but you still need to add "fetch" to the list of your supported UIBackgroundModes in your Info.plist.

You've implemented -[<UIApplicationDelegate> application:didReceiveRemoteNotification:fetchCompletionHandler:], but you still need to add "remote-notification" to the list of your supported UIBackgroundModes in your Info.plist.

I'm pretty sure these messages can be safely ignored so this is more just FYI.

Please update for latest version of swift

Issue with URL scheme handling

There is an issue with this implementation:

    @available(iOS 9.0, *)
    public func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
        return __services.reduce(true) { (previous, service) -> Bool in
            previous && (service.application?(app, open: url, options: options) ?? true)
        }
    }

The problem is when you have multiple application services. For instance we have a Facebook service and a payment service that can both be opened with a url. The issue is that the above code will start looping through until it gets to the first service that implements the url scheme check, in this case Facebook. As the url scheme is actually for the payment service, Facebook service correctly returns false. But this then causes no other service to be checked because previous is now false.

Access UIWindow

Where do i setup AppDelegate window and use it in the app where needed ?

Logical mistake

I think, you have logical mistake in will/didFinishLaunching methods.

PluggableApplicationDelegate/PluggableApplicationDelegate/Classes/ApplicationServicesManager.swift

Line 36 in e03cd1e

result = true

Now application will be launched if one service has true result. Though execution should be ended if one service has false result.

Probably you need create optional/required flag for service, to have control app launching.

Project is no longer supported

Hi guys.

It looks like this project is no longer supported (no updates, even no answers).
But it's a great idea and I use it on my own projects. 👍🏻

And I took the liberty of creating a new repo for future support. 🤓
I hope that the author will not object to this (I added him to Credits).

The new repo: https://github.com/pchelnikov/PluggableAppDelegate
I've already added some features from PRs and comments.

Please welcome for conversation and contribution. 🦄

application(_:openUrl:options:) not working

In line 91 of PluggableApplicationDelegate.swift there is the method called open func application(_ app: UIApplication, public url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Boo but this should be open func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool. Not public url: but open url:.
So an app using the PluggableApplicationDelegate currently can not handle the url it was opened with.

[Question] Deprecated UIUserNotificationSettings and UILocalNotification

Hi,
first nice idea, I appreciate this solution.

for sure do you know that Xcode gives us warnings in PluggableApplicationDelegate-Swift.h due to UIUserNotificationSettings and UILocalNotification are deprecated since iOS 10.

You already have scheduled update of ApplicationServicesManager.swift?

I ask because probably I can do it, but if you're working on it, has no sense to open in the future a PR about it :)

Thanks!

Custom UIWindow

For my project, I need to have a custom UIWindow. Without the PluggableApplicationDelegate, I used to do it like this:

    var customWindow: MyCustomWindow?
    var window: UIWindow? {
        get {
            customWindow = customWindow ?? MyCustomWindow(frame: UIScreen.main.bounds)
            return customWindow
        }
    }

When I keep this code in my AppDelegate itself, I get the following error on the var Window:

Overriding non-open var outside of its defining module

And when I put this code in a specific ApplicationService, it says that self.window is unknown.

Any clue how I can still have this custom UIWindow? Thanks!

Compile warning on application(_:open:sourceApplication:annotation:)

On Xcode 8.3:

Instance method 'application(:public:sourceApplication:annotation:)' nearly matches optional requirement 'application(:open:sourceApplication:annotation:)' of protocol 'UIApplicationDelegate'

Fix is to declare method as public rather than open

URLs aren't opening

A previous commit renamed application(open:sourceApplication:annotation) to application(public:sourceApplication:annotation)

This is the commit that broke it: 4119d03#commitcomment-22251301

How to separate for remoteControlEvents

I tried this to separate remoteControlEvents and my code looks like

import Foundation
import PluggableApplicationDelegate

final class MusicControlsAppService: NSObject, ApplicationService {
    
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
        UIApplication.shared.beginReceivingRemoteControlEvents()
        print("It has started!")
        return true
    }
    
    func applicationDidEnterBackground(_ application: UIApplication) {
        print("It has entered background")
    }
    
    override func remoteControlReceived(with event: UIEvent?) {
        if event?.type == .remoteControl {
            switch event!.subtype {
            case .remoteControlPlay:
                PlayerManager.shared.playTapped()
            case .remoteControlPause:
                PlayerManager.shared.pauseTapped()
            case .remoteControlTogglePlayPause:
                if PlayerManager.shared.isPauseActive {
                    PlayerManager.shared.playTapped()
                } else {
                    PlayerManager.shared.pauseTapped()
                }
            case .remoteControlNextTrack:
                PlayerManager.shared.nextTapped()
            case .remoteControlPreviousTrack:
                PlayerManager.shared.previousTapped()
            default:
                break
            }
        }
    }
}

This gives error for the method Method does not override any method from its superclass , also when override keyword is removed it doesn't get calls.

Can you assist to solve this ? As of now I am keeping that method in the main App delegate which is subclass of PluggableApplicationDelegate which works.

Carthage support

I'm using Carthage as my dependency manager and the last tagged version 0.1.2 does not work but what's currently on master does. Can you tag or release what's on master? Thanks!