How to do Swift Dependency Injection with Initializers

Swift Dependency Injection

Dependency Injection feel like a very complicated topic but in fact it is very simple. We as devs all try to follow design principle like SOLID so that our code is properly structured in a modular way and not a spaghetti code. Dependency injection really help with this. It also helps in mocking/testing our code.

Dependency injection literally means injecting the dependency. In programming world it means injecting the dependencies our code needs in order to work. There are three flavors of dependency injection in Swift

1. Initializer Based
2. Parameter Based
3. Property Based

In this blog we will focus on Initializer Based Dependency Injection. Lets take a look at this example 




If you look at the example above, FileUploader instance initialization is dependent on file manager and network manager. So this is a very tightly coupled code.  We can use initializer based Swift Dependency Injection to make this a little better


So this subtle change makes a huge difference, instead of hardcoding file manager and network manager in the init method of FileUploader we are passing the required/dependency as parameters externally. This is basically what dependency injection is. We will talk about other flavors of dependency injection in coming articles.

 



Popular posts from this blog

How to make an iOS App Secure?

Image
This is mobile era and pretty much everything these days can happen from our smart phone. Thanks to millions of apps out there which help us in accomplishing anything we want. Whether it is maintaining your schedule (calendar) to managing financial information on the go, all things can be done by mobile apps running on our smart phones. Since these apps have access to so much of confidential information, as developer when we make an app we need to follow highest security standards so that information is not accessed by someone who is not entitled for it.  When it comes to iOS devices there are more than billion active devices that use iOS apps on daily basis.  Here I am compiling the different security practices that an iOS developer should always keep in mind while developing apps. 1. Enable ATS in mobile apps  With launch of iOS 9 and ELCapitan Apple launch ATS (Apple Transport Security) which forces apps to only connect to secure network. This means any connection that application m
Read more

System Design Interview For Mobile Engineers

Image
Introduction As you gain seniority in Software Engineering, the system design interview becomes the most important interview. This interview is focused on your ability as an engineer to look at and understand the design of an application from a holistic level. You are expected to start from a high-level view and then do a deep dive into individual components. In this article, I have shared my recipe to approach the system design interview problem by going through an example. Sounds interesting?... Keep reading I find the system design interview interesting because they are most realistic, holistic, and involve great communication skills.  Approaching a System Design Problem So I watched different kinds of system design interviews tutorials and made  my own custom script that made sense to me as a mobile developer. By no way or means, this is a comprehensive list, this is just something that has worked for me. So here is the rundown of different sections I used to tackle the system desi
Read more

How to make iOS app secure from screenshot and recording?

Image
  Thanks to the mobile era we have mobile apps for everything these days. Every business from a barbers shop to huge retailers has apps so that they can be closer to their customers. On one hand, we really leverage this convenience but on the other hand, there are risks of exposing a lot of confidential information while using these apps. And it becomes very vital when dealing with payments and other sensitive information. As a developer of these apps, it is our responsibility to put checks to make sure privacy and security are not compromised. One of the ways is to detect/prevent screenshot and screen recording action and taken an action or inform the user to take appropriate action.  Use Cases Here are some use cases where screen capture and screen recording can expose sensitive information: 1. Login information can be recorded Any app that requires a login to get access to sensitive information. We need to make sure that only the intended person can log in. If screen recording or sc
Read more