Repository Example

Repository.swift

import RxSwift
import RxCocoa

class Repository {
  
  private let remoteDataSource: RemoteDataSource
  private let localDataSource: LocalDataSource
  
  private let errorRelay = PublishRelay<Error?>()
  
  init(remote: RemoteDataSource, local: LocalDataSource) {
    self.remoteDataSource = remote
    self.localDataSource = local
  }

  public func getHistory() -> Observable<History?> {
    return localDataSource.getHistory()
  }
  
  public func refreshHistory(id: Int) {
    _ = remoteDataSource.getHistory(id)
      .subscribe(onSuccess: { [weak self] history in
        self?.localDataSource.setHistory(history)
        }, onError: { [weak self] error in
          self?.errorRelay.accept(error)
      })
  }
  
  public func error() -> Observable<Error?> {
    return errorRelay.asObservable()
  }
}

class RemoteDataSource {
  
  public func getHistory(_ id: Int) -> Single<History> {
    // remote api
    return Single.just(History(id: 1, title: "remote", isFollow: true))
  }
}

class LocalDataSource {
  
  private var historyStore: BehaviorRelay<History?> = .init(value: nil)
  
  public func setHistory(_ history: History) {
    historyStore.accept(history)
  }
  
  public func getHistory() -> Observable<History?> {
    return historyStore.asObservable()
  }
}