MTC2018 - Implementing TypeErasure in ViewController

Speaker: Nobuo Saito

To develop our app, we use MicroViewController, which we introduced at iOSDC, and we have also implemented the idea of MicroFrameworks. A common issue with using MicroFrameworks is circular dependencies, but by using the MicroViewController model, we can implement TypeErasure for ViewController. We call this ViewControllerRequest. Today I will talk about ViewControllerRequest, our prized service that solved the problem of circular dependencies and greatly reduced the work required for refactoring.

Transcript

1. Implementing TypeErasure in ViewController Nobuo Saito Tech Lead (iOS)
2. Making TypeErasure for ViewController
3. Tech Lead iOS Nobuo Saito
4. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
5. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
6. iOSDC Review MicroViewController = One of the microservices implemented in iOS github.com/mercari/Mew
7. TableView CollectionView Auto/manual sizing LifeCycle/reuse
8. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
9. iOS Technical Debt Massive ViewController 1 layer Objective-C Tight binding between classes
10. Technical Debt? linux swiftc UIKit
11. Increase in maintenance cost Negative influence from knowledge of existing code The Nature of Technical Debt
12. Technical Assets Features work properly Features can be reused New features are not added Code cannot be accessed
13. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
14. All modules import Kit/Entity The app imports all modules 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3
15. Pros of Microframeworks project.pbxproj Swift internal Reduces unnecessary sharing
16. Cons of Microframeworks Circular dependency Dynamic linking time Bundle Not supported by some OSS
17. Cons of Microframeworks Circular dependency Dynamic linking time Bundle Not supported by some OSS
18. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 ItemDetail cannot import Search
19. Overloads functions: (Request) -> Response
20. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Get all Mercari resources from EnvironmentProvider EnvironmentProvider User GetProfileRequest MercariEnvironment
21. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Definition of request Type class, Type implementation DIP (Dependency Inversion Principle) protocol struct function
22. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
24. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 3 protocols defined in MercariKit Injectable/Interactable
25. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Make ViewControllers Input/Output in MercariEntity Injectable/Interactable Input Output
26. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Mercari can import Search Injectable/Interactable Input Output let vc = SearchVC(...)
27. 　　　 MercariKit
28. 　　　 MercariKit
29. 　　　 MercariKit
30. 　　　 MercariEntity
31. 　　　 Mercari
32. 　　　 ItemDetail
33. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Get ViewController instance from EnvironmentProvider API Gateway for VC ViewControllerRequest Search IO let vc = SearchVC(...)
34. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 Code cannot be referenced Features work properly
35. 　　　 MercariKit 　　　 MercariEntity 　　　 Prod1 　　　 Listing 　　　 ItemDetail 　　　 Search 　　　 Mercari 　　　 Prod2 　　　 Prod3 ＿人人人人人人人人＿ ＞Huge buried treasure!＜ ￣Y^Y^Y^Y^Y^Y^Y^￣ ViewControllerRequest ViewControllers IO WrapperOfObjC
36. Agenda What’s New in Mercari/Mew Technical Debt/Assets Composition of Mercari iOS ViewControllerRequest Conclusion
37. Conclusion Divide the framework Split duties and turn liabilities into assets To do that, types should be well-defined