AKIBA.swift: Layered ArchitectureにおけるRxSwiftを用いたErrorの伝搬

https://classmethod.connpass.com/event/53603/

Transcript

1. Layered Architectureʹ͓͚Δ RxSwiftΛ༻͍ͨErrorͷ఻ൖ Kyobashi.swift Recruit Marketing Partners
2. ࣗݾ঺հ • Takeshi Ihara / @nonchalant0303 • Recruit Marketing Partners • iOS Engineer
3. RxSwiftʹContribute͠·ͨ͠
4. Layered Architecture *OGSB 1SFTFOUBUJPO %PNBJO
5. Layered Architecture *OGSB
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6. Error *OGSB 1SFTFOUBUJPO %PNBJO $POOFDUJPO 6OBVUIPSJ[FE 4FSWFS
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7. *OGSB 1SFTFOUBUJPO %PNBJO $POOFDUJPO 4FSWFS
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   3FUSZ Each Error, Each Process
8. ͜ͷ֤૚ͷErrorΛͲ͏΍ͬͯ RxSwiftΛ࢖ͬͯ ϋϯυϦϯά͢Δ͔͕ࠓճͷ࿩
9. RxSwift Rx is a generic abstraction of computation expressed through Observable<Element> interface. This is a Swift version of Rx.
10. class ViewController: UIViewController { … override func viewDidLoad() { super.viewDidLoad() presenter.prepare() .subscribe( onNext: { domainModel in // Viewʹ൓ө }, onError: { error in // Τϥʔॲཧ } ) .addDisposableTo(disposeBag) } } subscribe - onError Ͳ͜Ͱى͖ͨΤϥʔ͔෼͔Βͳ͍ʜ
11. ·ͣ͸
12. ֤૚ͷΤϥʔΛఆٛ [Infra] enum InfrastructureError: Error { case connection case anthorization } extension InfrastructureError { static func create(error: Error) -> InfrastructureError { ... return infraError } }
13. ֤૚ͷΤϥʔΛఆٛ [Domain] enum DomainError: Error { case logic case translation } extension DomainError { static func create(error: Error) -> DomainError { ... return domainError } }
14. ֤૚ͷΤϥʔΛఆٛ [Presentation] enum PresentationError: Error { case connection case unknown }
15. Layered Architecture x RxSwift *OGSB 1SFTFOUBUJPO %PNBJO 0CTFSWBCMF&OUJUZ 0CTFSWBCMF%PNBJO.PEFM "1*
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16. Layered Architecture x RxSwift *OGSB 1SFTFOUBUJPO %PNBJO 0CTFSWBCMF&OUJUZ 0CTFSWBCMF%PNBJO.PEFM "1*
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17. public static func error(_ error: Swift.Error) -> Observable<E> { return ErrorProducer(error: error) } Observable.error ObservableType.catchError public func catchError(_ handler: @escaping (Error) throws -> RxSwift.Observable<Self.E>) -> RxSwift.Observable<Self.E> 0CTFSWBCMFʹแΜͩΤϥʔΛੜ੒͢Δ 0CTFSWBCMFͷதͰൃੜͨ͠ΤϥʔΛ
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18. protocol Repository { func find() -> Observable<Entity> } struct RepositoryImpl: Repository { … func find() -> Observable<Entity> { return apiClient.send() .catchError { return Observable.error(InfrastructureError.create(error: $0)) } } } %PNBJO૚ʹެ։͢Δ*OUFSGBDF ͜͜Ͱ"1*͔Βฦ͖ͬͯͨ&SSPSΛ
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19. struct Translator { static func translate(entity: Entity) throws -> DomainModel { ... throw DomainError.translation ... return domainModel } } protocol UseCase { func prepare() -> Observable<DomainModel> } struct UseCaseImpl: UseCase { … func prepare() -> Observable<DomainModel> { return repository.find() .map { try Translator.translate(entity: $0) } } } NBQͰUISPX͞ΕͨΒ
    0CTFSWBCMFFSSPSʹͳΔ %PNBJO
20. struct Presenter { … func prepare() -> Observable<DomainModel> { return useCase.prepare() .catchError { error in guard let infraError = error as? InfrastructureError else { return Observable.error(PresentationError.unknown) } switch infraError { case .connection: return Observable.error(PresentationError.connection) default: return Observable.error(PresentationError.unknown) } } } } 1SFTFOUBUJPO ಛఆͷ&SSPSܕͷͱ͖ʹ
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21. ͋ͱ͸PresentationErrorͷܕ ΛݟͯݸผͷॲཧΛ͢Ε͹
22. *OGSB 1SFTFOUBUJPO %PNBJO $POOFDUJPO 4FSWFS
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    3FUSZ Each Error, Each Process
23. ·ͱΊ • Layered Architecture x RxSwiftͷΤϥʔ఻ ൖʹ͍ͭͯͷҰྫΛߟ͑ͨ • catchError͸errorΛฦͣ͞ճ෮ॲཧ΋ॻ͚ ΔͷͰҟৗܥ͔Βਖ਼ৗܥʹ໭Δ͜ͱ΋Մೳ