Photo courtesy of www.kevinandamanda.com

Dip is a simple Dependency Injection Container.

It's aimed to be as simple as possible yet provide rich functionality usual for DI containers on other platforms. It's inspired by .NET's Unity Container and other DI containers.

• You start by creating let container = DependencyContainer() and registering your dependencies, by associating a protocol or type to a factory.
• Then you can call container.resolve() to resolve an instance of protocol or type using that DependencyContainer.

You can easily use Dip along with Storyboards and Nibs - checkout Dip-UI extensions.

Dip is completely documented and comes with a Playground that lets you try all its features and become familiar with API. You can find it in Dip.xcworkspace.

Note: it may happen that you will need to build Dip framework before playground will be able to use it. For that select Dip-iOS scheme and build.

You can find bunch of usage examples in a wiki.

There are also several blog posts that describe how to use Dip and some of its implementation details:

• IoC container in Swift
• IoC container in Swift. Circular dependencies and auto-injection
• Dependency injection with Dip

File an issue if you have any question.

• Scopes. Dip supports 4 different scopes (or life cycle strategies): Prototype, ObjectGraph, Singleton, EagerSingleton;
• Named definitions. You can register different factories for the same protocol or type by registering them with tags;
• Runtime arguments. You can register factories that accept up to 6 runtime arguments;
• Circular dependencies. Dip can resolve circular dependencies;
• Auto-wiring & Auto-injection. Dip can infer your components' dependencies injected in constructor and automatically resolve them as well as dependencies injected with properties.
• Storyboards integration. You can easily use Dip along with storyboards without ever referencing it in your view controller's code;
• Easy configuration. No complex container hierarchy, no unneeded functionality;
• Thread safety. Registering and resolving components is thread safe;
• Helpful error messages. If something can not be resolved at runtime Dip throws an error that completely describes the issue;

import Dip

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    // Create the container
    private let container = DependencyContainer() { container in
    
        // Register some factory. ServiceImp here implements protocol Service
        container.register { ServiceImp() as Service }
    }

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { 
        
        // Resolve a concrete instance. Container will instantiate new instance of ServiceImp
        let service = try! container.resolve() as Service
    
        ...
    }
}

import Dip

class AppDelegate: UIResponder, UIApplicationDelegate {
	private let container = DependencyContainer.configure()
	...
}

//CompositionRoot.swift
import Dip
import DipUI

extension DependencyContainer {

	static func configure() -> DependencyContainer {
		return DependencyContainer() { container in 
			container.register(tag: "ViewController") { ViewController() }
			  .resolveDependencies() { container, controller in
				  controller.animationsFactory = try container.resolve() as AnimatonsFactory
			}
    
			container.register() { AuthFormBehaviourImp(apiClient: $0) as AuthFormBehaviour }
			container.register() { [unowned container] container as AnimationsFactory }
			container.register() { view in ShakeAnimationImp(view: view) as ShakeAnimation }
			container.register() { APIClient(baseURL: NSURL(string: "http://localhost:2368")!) as ApiClient }
		}
	}

}

extension DependencyContainer: AnimationsFactory { 
    func shakeAnimation(view: UIView) -> ShakeAnimation {
        return try! self.resolve(withArguments: view)
    }
}

extension ViewController: StoryboardInstantiatable {}

//ViewController.swift

class ViewController {
    var animationsFactory: AnimationsFactory?

    private let _formBehaviour = Injected<AuthFormBehaviour>()
    
    var formBehaviour: AuthFormBehaviour? {
        return _formBehaviour.value
    }
	...
}

Since version 4.3.1 Dip is built with Swift 2.2. The lates version built with Swift 2.1 is 4.3.0.

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

pod "Dip"

If you use Carthage add this line to your Cartfile:

github "AliSoftware/Dip"

If you use Swift Package Manager add Dip as dependency to you Package.swift:

let package = Package(
  name: "MyPackage",
  dependencies: [
    .Package(url: "https://github.com/AliSoftware/Dip.git", "4.4.0")
  ]
)

On OSX you can run tests from Xcode. On Linux you need to have Swift Package Manager installed and use it to build test executable:

cd Dip/DipTests
swift build
./.build/debug/DipTests

This library has been created by Olivier Halligon.
I'd also like to thank Ilya Puchka for his big contribution to it, as he added a lot of great features to it.

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

The animated GIF at the top of this README.md is from this recipe on the yummy blog of Kevin & Amanda. Go try the recipe!

The image used as the SampleApp LaunchScreen and Icon is from Matthew Hine and is under CC-by-2.0.