Mastering the VIPER structure – The.Swift.Dev.

After writing my finest practices article about VIPER, I’ve made just a few adjustments to the codebase. I used to be enjoying with these concepts in my thoughts already, however by no means had sufficient time to implement them correctly. Let’s me present you the adjustments…

VIPER protocols

My generic situation was that I needed to have a frequent interface for each single module part. That is why I created easy protocols for the next:

• View
• Interactor
• Presenter
• Entity
• Router
• Module

This manner for instance my router objects are implementing the Router protocol, so if I make an extension on it, each single one can have that specific performance. It is a fairly small, however very nice addition that makes my modules far more highly effective than they have been earlier than. Actually talking I ought to have had this from the very starting, however anyway to any extent further it is gona be like this. 😬

This transfer implied to arrange my VIPER protocols right into a customized framework, so I made one, with these parts. You will discover it on github, it is a actually fundamental one, be at liberty to make use of it, you simply need to import VIPER in your challenge.

Module protocols

Since I used to be utilizing VIPER it had this nice urge to implement a customized module for presenting system default alert messages on iOS. You realize UIAlertController is the one I am speaking about. Really Robi (my true metallic pal) prompt a surprisingly good basic resolution for the issue. His concept gave the impression of this:

Why do not we create a protocol for the router, so we might implement this on each different router, additionally we might merely name present(alert:) on them?

I beloved this method, so we have constructed it. Turned out, it is freakin superior. So we launched a brand new protocol for the module router, carried out a default protocol extension and voilà routers at the moment are able to presenting error messages.

Notice that you need to use the identical sample for plenty of different (comparable) issues as effectively. The essential implementation appears to be like like this one under, I hope you get the thought. 💡

import VIPER

class AlertModule: Module {
    
}

protocol AlertModuleRouter: class {

    func present(alert: AlertEntity)
}

extension AlertModuleRouter the place Self: Router {

    func present(alert: AlertEntity) {
        
    }
}



protocol MyModuleRouter: Router, AlertModuleRouter {

    
}

After all this system can work for different VIPER parts as effectively, it is fairly simple to implment and the protocol oriented method provides us an enormous win. 🏆

Presenter to presenter interactions

I additionally modified my thoughts in regards to the place of the delegate implementations collaborating within the module communication stream. In my final article I instructed you that I am storing the delegate on the router, however in a while I noticed that delegation is generally associated to enterprise logic, so I merely moved them to the presenter layer. Sorry about this. 🤷‍♂️

import VIPER

protocol AModulePresenterDelegate {
    func didDoSomething()
}

class AModule: Module {

    func construct(with delegate: AModulePresenterDelegate? = nil) -> UIViewController {
        

        presenter.delegate = delegate

        

        return view
    }
}

class AModulePresenter: Presenter {

    func someAction() {
        self.delegate?.didDoSomething()
        self.router?.dismiss()
    }
}



class BModulePresenter: Presenter, AModulePresenterDelegate {

    func didDoSomething() {
        print("Howdy from module A!")
    }
}

This manner you possibly can skip the complete router layer, plus all of the enterprise associated logic shall be carried out within the presenter layer, which needs to be the one option to go. 🤪

Entities are right here to remain

Aside from the service layer generally it is fairly helpful to have an entity wrapper with some further metadata for the mannequin objects. That is why I additionally made an Entity protocol, and began to make use of it in my modules. For instance an online view module that may open a hyperlink can have a WebViewEntity with a title and a content material url property. 😅

import VIPER

struct AlertEntity: Entity {
    let title: String
    let message: String
}

The pattern alert module from above can use an AlertEntity with some properties that may outline the title, message or the buttons. This manner you do not actually have to consider the place to place these objects, as a result of these are the actual VIPER entities.

IO protocols

It is a WIP (work-in-progress) concept that I would wish to check out, however the fundamental idea is considerably like that I wish to separate enter and output protocols for VIPER module layers. Additionally this IO differentiation could be mirrored on the service layers too (perhaps the entire object “mess” from the service layer goes for use as IO entities sooner or later), by mess I imply that there could be manner too many objects within the Service/Objects listing, so which means these might be additionally grouped by modules (aka. entities).

Anyway, I am pondering of one thing like RequestEntity, ResponseEntity for service communication, and for the VIPER layer communication I might think about two separate protocols, eg. PresenterInput, PresenterOutput. We’ll see, however at first sight, it is looks like fairly an overengineered factor (hahaha, says the VIPER advocate 😂).

VIPER vs [put your architecture name here]

No! Please do not suppose that x is best than y. Architectures and design patterns are easy instruments that may be utilized to make your life simpler. In the event you do not like x, you need to attempt y, however you shouldn’t blame x, simply because that is your private opinion.

My present favourite structure is VIPER, so what? Perhaps in a 12 months or two I will go loopy in love with reactive programming. Does it actually issues? I do not suppose so. I’ve realized and tried so many issues through the previous, that I can not even keep in mind. 🧠

I am additionally consistently making an attempt to determine new issues, as you possibly can see this entire sequence of articles about VIPER is the results of my studying progress & experiences. In the event you actually wish to grasp one thing, you need to observe, analysis and check out lots, and most significantly be pleased with your successes and keep humble on the similar time. 🙏

That is it in regards to the VIPER structure for some time. I hope you loved studying the entire sequence. If in case you have any questions, be at liberty to ask me by twitter. 💭