Valhalla

Overview

This project is an attempt at learning the granular principles behind IoC containers. Valhalla is meant solely for learning purposes, and will remain dev-only for quite some time.

I was inspired by Dip, found here. To dive deeper into principles and general concepts of Dependency Injection and IoC, check out Deurson and Seemann's Dependency Injection book.

Integration

You can integrate Valhalla to your project by adding it to your podifle:

pod 'Valhalla'

Import it wherever you need it.

Usage

Ideally, you may want to have a central location where all dependecies are declared. Valhalla is supposed to be an IoC container. Here's an example of how you'd declare dependencies with Valhalla.

First, some context:

• I'll assume there's a AppDependencyContainer file, where all dependencies can be registered.
• Since Valhalla returns a container of registered dependencies, you'll pass this container down to wherever it's needed (according to your app architecture's guidelines).

Registration

// Example

// AppDependencyContainer.swift

public static func create() -> DependencyContainer {
        return DependencyContainer { container in
            container.register(type: AuthenticationManager.self,
                               service: KiraAuthenticationManager())
            
            container.register(type: PreferenceManager.self,
                               service: PreferenceManager())
            
            container.register(type: SessionManager.self,
                               service: SessionManager())
        }
    }

Resolution

To resolve your dependencies, you'll do something like:

dependencyContainer.resolve(type: PreferenceManager.self) ?? PreferenceManager()