The document discusses the architecture of an iOS application using reactive programming principles. It outlines the common layers of an application including the transport, service, model, view model and view layers. It then shows how each layer can be implemented using the ReactiveCocoa framework by turning components into signals and streams that can be combined, transformed and manipulated. Key concepts discussed include actions, signals, signal producers, operators like map and flatMap, and presenting values to the view layer.

1. Рак мозга или мозг рака
Раком можно все

2. 1023

3. A for Architecture

4. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer

5. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Persistence
Notifications
Runtime

6. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
NSNotification
LocationUpdate

7. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Networking
Networking policies

8. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
HTTP.Request
HTTP.Response
HTTP.Error

9. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
API Request
Persistence Request
Application Service wrapper

10. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Update request
Value Object
Service Object

11. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Business logic
Logic state

12. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Model Object

13. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Application State
Presentation Logic

14. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Bindings
Presentables

15. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Presentation
UI State

16. •Application Layer
•Transport Layer
•Service Layer
•Model Layer
•ViewModel Layer
•View Layer
Presenters
UIObjects
Foundation Types

17. Data Flow

18. 1024

19. Data + Data Request Flow

20. Transport Layer

21. Transport Layer

22. Transport Layer + Errors

23. Transport Layer + Binding

24. And now?

25. RAC
• Signal
• SignalProducer
• Action
• Property
• Result

26. RAC
• Signal
• SignalProducer
• Action
• Property
• Result
• Pipeline
• Future Task
• Future Builder
• Reactive State
• Enum<Value | Error>

27. RAC
• Signal
• SignalProducer
• Action
• Property
• Result
• NSNotificationCenter
• startWithCompletion:
• startWithInput:Completions
• value + KVO
• completions(result, error)

28. RAC + Transforms
• Signal -> Signal - Operator
• Signal.map(transform)
• Signal.retry(3)
• Signal -> Signal -> Signal - pipeline
- retry(map(signal, transform), 3)
✓ signal.map(transform).retry(3)

29. RAC + (flat)map

30. Transport Layer + RAC

31. Transport Layer + RAC
let requestAction = Action<URLRequest, URLResponse, Error> { .../*future task*/ }
let http = Action<Request, Response, Error> { request in
return Result<Request, Error>(value: request)
.flatMap(serialize) //Result<JSON, Error>
.flatMap(requestBuilder(forConfiguration: configuration)) //Result<URLRequest, Error>
.map(SignalProducer.init) //SignalProducer<URLRequest, Error>
.flatMap(.Latest, transform: requestAction.apply) //SignalProducer<URLResponse, Error>
.attemptMap(deserialize) //SignalProducer<Response Error
}
Заметьте - эта штука вполне может
быть общей вне зависимости от
входных и выходных данных засчет
generic

32. Build Your Own RAC
extension SignalType {
/// Returns a signal that will yield an array of values when `self` completes.
@warn_unused_result(message="Did you forget to call `observe` on the signal?")
public func collect() -> Signal<[Value], Error> {
return self
.reduce(CollectState()) { $0.append($1) }
.map { $0.values }
}
}

33. Transport Layer + RAC
let httpWithPolicy = Action<Request, Response, Error> { request in
http.apply(request)
.retry(3)
.suspendOn(enterBackgroundSignal: background, enterForeground: foreground)
}

34. Service Layer

35. Service Layer

36. Service Layer + RAC
let service = Action<Number, Image, Error> { number in
let image = cacheService.inquire
.apply(number)
.concat { xkcdImageHTTP.apply(number) }
let description = xkcdDescriptionHTTP.apply(number)
return combineLatest(image, description).map { ImageWithDescription(image: $0, description: $1) }
}

37. Model Layer

38. Model Layer

39. Model Layer + RAC
struct State {
let number: Int
let value: AnyProperty<ImageWithDescription?>
init(number: Int) {
self.number = number
self.value = AnyProperty(value: nil, producer: service.apply(number))
}
}
let state = MutableProperty(State(number: 100))
let increment = { number.value = State(number: number.value.number + 1) }
let exposedState = AnyProperty(state)

40. View Model Layer

41. View Model Layer

42. VM Layer + RAC
let image = model.exposedState
.flatMap { $0.value.image }
.map { $0 ?? imagePlaceholder }
let description = model.exposedState
.flatMap { $0.value.description }
.map { $0 ?? "Loading..." }
let rightButtonAction = model.increment
let present = { presenters in
presenters.rightButtonAction <~ rightButtonAction
presenters.description <~ description.producer
presenters.image <~ description.image
}

43. View Layer

44. View + RAC
class View {
//{ self.imageView.image = $0 }
let image: Presenter<UIImage> = self.imageView.imagePresenter
//{ self.descriptionLabel.value = $0 }
let description: Presenter<String> = self.descriptionLabel.textPresenter
//{ self.button.clickedSignal.observe($0) }
let rightButton: Presenter<() -> ()> = self.button.clickActionPresenter
}

45. Hm…

46. Benefits?
• Consistency
• Observability
• Testability
• Encapsulation
• Completeness

47. Examples?
Popup Action
Navigation Property + Actions
UIKit Sinks + Presentables
Login Form Action + Operators

48. What’s next?
• RXMarbles (http://rxmarbles.com/)
• Reactive Cocoa sources - all here

49. Questions?