Clean architecture workshop
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This document discusses implementing Clean Architecture in iOS apps. It provides an agenda for a training on the topic, including understanding Clean Architecture concepts, implementing rules, and an example app called RealProgrammers. The first user story of displaying a list of programmers is implemented as an example, including defining the interactor, presenter and view components and their responsibilities, as well as the entity gateway.
![#Swift3Arch
Tricky question
★ If [Model] + [View] + [Controller /
Presenter / View Model] = [TheApp]
★ How can Controller != Presenter != View
Model?
★ Responsibilities matter!
★ Other components (patterns) might be
involved.](https://image.slidesharecdn.com/cleanarchitectureworkshophalfdayedition-161122143055/85/Clean-architecture-workshop-14-320.jpg)
Clean architecture workshop
- 1. #Swift3Arch Implementing Clean Architecture in iOS Jorge D. Ortiz-Fuentes @jdortiz
- 3. #Swift3Arch Agenda ★ Goals ★ Before Clean Architecture ★ Clean Architecture Concepts ★ Implementation rules ★ Example App: RealProgrammers ★ Implement 1st User Story ★ References
- 4. #Swift3Arch Full Version: 3d ★ MVX • Learn • Extract MVP ★ 1st User Story • Use Case • Presenter • View • Entity Gateway • Initial connection ★ Connectors • Memory Management • Reuse ★ 2nd user story: add • Navigation: Modal vs Push • Command pattern • Immutables • Observation ★ 3rd user story: detail • Identity • Use case factories • 2nd use case in the same view ★ Other use cases: just logic ★ Forward flow synchronization ★ Dependency Injection ★ Asynchrony • Async entity gateway • Other tasks
- 5. #Swift3Arch LIVE Online Training ★ 3 days (same weekday 3 continuous weeks) ★ Máx 10 people ★ Live coding shared via video conference ★ Chat running all the time ★ Complete repo with many commits and Tests> 95% ★ Additional exercises ★ Ask as much as you want!
- 7. Goals
- 8. #Swift3Arch Goals ★ Understand the concepts ★ Learn the sources ★ Implement the ideas of the Clean Architecture in a real app ★ Grow from here
- 12. #Swift3Arch Before Clean Architecture ★ MVC ★ MVP ★ MVVM
- 13. – Martin Fowler “Different people reading about MVC in different places take different ideas from it and describe these as 'MVC'. If this doesn't cause enough confusion you then get the effect of misunderstandings of MVC that develop through a system of Chinese whispers.”
- 14. #Swift3Arch Tricky question ★ If [Model] + [View] + [Controller / Presenter / View Model] = [TheApp] ★ How can Controller != Presenter != View Model? ★ Responsibilities matter! ★ Other components (patterns) might be involved.
- 15. #Swift3Arch The goal ★ Separation of responsibilities into roles. Is it? Not historically. Other motivations. Solving problem d’jour. ★ Now why? • Testability • Reusability • Extensibility
- 16. #Swift3Arch MVC: The early days ★ Separated presentation: Model <-> Presentation (= V+C) ★ Observer originated from MVC, but observing full object (properties = scalars) ★ Variations: Passive model, i.e. model cannot send updates (for example HTTP)
- 17. #Swift3Arch Apple’s MVC ★ View • Only UIView subclasses • Show information and handle input to generate higher level events passed to controller • Fully reusable views library. Consistent L&F ★ Controller • Views delegate / control what’s displayed • Receive the events and converts them into calls to the model. • Knows about changes in the model and update what is displayed on the view. Typically a UIViewController. Responsible of presentation logic. ★ Model • Contain the business logic. No references to the UI. Flow synchronization vs Observer synchronization MVC = Composite + Strategy + Observer
- 19. #Swift3Arch Apple’s MVC: testability ★ The views are somebody else's (Apple's) problem. ★ Model is easy to test. ★ Controller is huge & has dependencies on the model and on the views => Complex to test. ★ Too many levels of abstraction, only a few methods exposed. ★ Some stuff in view controller that it is usually not tested.
- 20. MVP
- 22. MVVM
- 23. MVVM View Model ModelView Events & Info Operations Changes Changes
- 25. #Swift3Arch Clean Architecture ★ Uncle Bob’s (Robert C. Martin’s) architecture ★ Based in Onion, in turn based in hexagonal, DCI and some others
- 26. Clean Architecture App Delegate View (VC) Presenter Interactor Entity Gateway Connector
- 27. Persistance FW View Network LocationFW Presenter Entity Gateway Clean Architecture Interactor Entity
- 29. #Swift3Arch Rules ★ We are going to develop one module at a time ★ Follow the dependency rules ★ YAGNI ★ No early optimization applied ★ It is easy to add tests, but no TDD in 3h OK??
- 31. #Swift3Arch Features ★ Add potential candidates (Name, email, and important skills) ★ Show list of programmers with relative interview date ★ Remove candidates from list ★ Edit the data of any candidate ★ Contact candidate by email ★ Sync between devices ★ Universal app ★ Eye candy ★ iOS/macOS/watchOS/tvOS? ★ Credits
- 32. #Swift3Arch MVP Features ★ Add potential candidates (Name, email, and important skills) ★ Show list of programmers with relative interview date ★ Remove candidates from list ★ Edit the data of any candidate ★ Contact candidate by email ★ Sync between devices ★ Universal app ★ Eye candy ★ iOS/macOS/watchOS/tvOS? ★ Credits
- 33. Implementing the 1st User Story
- 34. I feel like I could Take On the World!
- 35. #Swift3Arch First User Story ★ Show a list of data elements to the user.
- 37. #Swift3Arch Interactor ★ Grab data from the entity gateway ★ Convert it to what is needed to be presented ★ Pass the results to the presenter ★ Start by defining the protocols
- 39. #Swift3Arch Presenter ★ Direction: only from interactor to view ★ Configure the (dumb) view with the data provided to it ★ Create the protocol for the view (Simplest wins!)
- 41. #Swift3Arch View ★ Combination of Views + View Controller ★ Make it dumb (passive), but useful ★ Tell the presenter about the relevant events ★ Keep them decoupled
- 43. #Swift3Arch Back to the Presenter ★ Implement responses to the user events. ★ Use the interactor ★ Add presentation logic to the presenter part
- 44. #Swift3Arch Presentation Logic ★ Date should be relative (“Today”, “1d ago”, “2w ago”) ★ That means current date is a dependency that we want to control for tests ★ Use lazy instantiation for the current date
- 46. #Swift3Arch Entity Gateway ★ Basic ★ Defer the decision of the persistence framework for later. ★ Implement the minimum functionality in a basic object. ★ Implications of the repository pattern.
- 47. References
- 48. #Swift3Arch References ★ http://martinfowler.com/eaaDev/ uiArchs.html ★ https://blog.8thlight.com/uncle-bob/ 2012/08/13/the-clean-architecture.html ★ https://cleancoders.com/episode/clean- code-episode-7/show
- 49. Thank you!