VIPER Architecture Pattern for iPhone App Development

Having knowledge of Software architecture in the software industry is very critical and it is important to design the code so that each of its piece is easily understandable, has a specific purpose and fits together with other pieces of code in a logical manner. The code should be easy to maintain, scale up and should be high in quality.

When you are following iPhone App Development and developing an iOS app then it is important to decide about which iOS project architecture you will use. Here in this article, we will talk about VIPER architecture, one of the most popular alternatives to MVC which keeps your code well organized, improves your development process and has many benefits. 

What Is Viper Architecture?

VIPER stands for View, Interactor, Presenter, Entity and Router. This architecture is based on the Single Responsibility Principle which leads to a very clean architecture and a better structure for your iOS project. VIPER is actually a design principle which implements separation of concern paradigm. It follows modular approach. One function, one module. For each module VIPER has five different classes with different roles and No class go beyond its basic purpose. These classes are as follows:- 

View: This class has all the code to show the app interface to the user and get their response. After receiving the response View alerts the presenter. 

Interactor: This class is the backbone of an application as it contains the business logic which is described by the use cases in the application. The interactor is actually responsible for fetching data from the model layer and its implementation is not dependent on user interface. 

Presenter: This is nucleus of a module. It gets user response from the View and work accordingly. This is the only class which communicate with all other components. It calls the router for wire-framing, Interactor to fetch data(network or local data calls) and View to update the UI.

Entity: This class contains basic model object used by the Interactor. It has part of the responsibilities of the model layer in other architectures.

Router: It has all the navigation logic for describing which screens are to be shown when. 

In VIPER architecture, each block corresponds to an object with specific tasks, inputs and outputs. The main aim behind this architecture pattern is to isolate your app’s dependencies and  balancing the delegation of responsibilities among the entities. Basically, VIPER architecture divides your application logic into smaller layers of functionality, each of them with a predefined responsibility. This makes it to test the interactions at the boundaries between layers easier. It also fits well with unit testing and makes your code more usable.

Benefits of VIPER Architecture:-

• It simplifies complex projects. In VIPER as modules are independent hence it is good for large teams.

• It makes the project scalable by enabling developers to simultaneously work on it as smoothly as possible.

• It decouples the code for reusability and testability.

• It divides the application components based on roles.

• It sets clear responsibilities.

• It makes it easy to add new features.

• It makes it easy to write automated tests as the UI logic is separate from business logic.

• It creates clear and well defined interfaces which are independent of other modules. 

• It makes it easier to track issues via crash reports due to the single responsibility principle. 
•  It makes the source code more cleaner, more compact and reusable.

Conclusion
Although VIPER architecture has lots of benefits but it is better to use it only for big and complex projects. As there are so many elements involved hence this architecture causes an overhead when starting a new small project. Hence it may not be appropriate to use VIPER for small projects which do not aim to scale up. VIPER architecture is a great solution for building working software and this is reason to cheer about for iOS apps. No doubt so many iOS developers will continue to use VIPER architecture due to its so many benefits.