How to build a messenger V3.0

Transcript

1. Rakhimov Andrii andrii.rakhimov@gmail.com
2. ➔ ➔ ➔ ➔ ➔ ➔ Agenda
3. Story Story
4. Story
5. Features ➔
6. Features ➔ ➔
7. Features ➔ ➔ ➔
8. Features ➔ ➔ ➔ ➔
9. Features ➔ ➔ ➔ ➔ ➔
10. Features ➔ ➔ ➔ ➔ ➔ ➔
11. Features ➔ ➔ ➔ ➔ ➔ ➔ ➔
12. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat Features
13. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat ➔ Blacklist user Features
14. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat ➔ Blacklist user ➔ Different types of chats ➔ Search Features
15. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat ➔ Blacklist user ➔ Different types of chats ➔ Search ➔ Chat with Lalafo Features
16. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat ➔ Blacklist user ➔ Different types of chats ➔ Search ➔ Chat with Lalafo ➔ Automate response ➔ ... Features
17. Telegram
18. Business needs
19. WEB client Business needs
20. WEB client Business needs
21. WEB client Business needs
22. Telegram Codebase 546 743 LOC
23. Resources
24. Resources
25. Resources
26. Variety of market solutions
27. Transport
28. HTTP
29. HTTP
30. HTTP + Firebase Cloud Messaging
31. HTTP + Firebase Cloud Messaging
32. HTTP + Firebase Cloud Messaging
33. Bidirectional transport
34. Bidirectional transport
35. Messaging protocols
36. WEB client
37. WEB client
38. WEB client Reconnects
39. Socket.IO
40. Bidirectional transport
41. Acknowledgment
42. Acknowledgment
43. Duplicate messages
44. Duplicate messages
45. Time sync and message order
46. Time sync and message order
47. Time sync and message order
48. Android
49. Battery concerns
50. Battery concerns val lifecycleObserver = object : LifecycleObserver { @OnLifecycleEvent(Lifecycle.Event.ON_START) fun onEnterForeground() { socketClient.connect() } @OnLifecycleEvent(Lifecycle.Event.ON_STOP) fun onEnterBackground() { socketClient.disconnect() } } ProcessLifecycleOwner.get().lifecycle.addObserver(lifecycleObserver)
52. Auth
53. Auth val authListener = object : AuthListener { override fun logIn() { socketClient.connect() } override fun logOut() { socketClient.disconnect() } } userOperations.register(authListener)
54. Auth
55. FCM val fcmListener = object : MessageListener { override fun onMessageReceived() { socketClient.connect() } } fcmOperations.register(fcmListener)
56. Auth Reconnects
57. Auth val authListener = object : AuthListener { override fun logIn() { socketClient.connect() } override fun logOut() { socketClient.disconnect() //more things to do... } } userOperations.register(authListener)
58. Auth Reconnects State Machines
59. State machines sealed class LifecycleState { object AppStarted: LifecycleState() object AppEnteredForeground: LifecycleState() object AppEnteredBackground: LifecycleState() object LoggedIn: LifecycleState() object LoggedOut: LifecycleState() object Reconnected: LifecycleState() object Disconnected : LifecycleState() data class MessageReceived(val message: Any): LifecycleState() }
60. State machines private val authListener = object : AuthListener { override fun logIn() { lifecycleListener.onStateChanged(LifecycleState.LoggedIn) } override fun logOut() { lifecycleListener.onStateChanged(LifecycleState.LoggedOut) } } authOperations.register(authListener)
61. State machines fun onStateChanged(state: LyfecycleState) { when(state){ Reconnected ->... AppStarted -> { socketClient.connect() unreadCounterOperations.syncUnreadCounter()... } AppEnteredForeground ->... AppEnteredBackground -> { socketClient.disconnect()... } LoggedIn ->... }
62. State machines
63. foreground services
64. Firebase Cloud Messaging
65. + Workmanager =
66. ➔ Real time send/delivery 1:1, 1:n ➔ Image/File sending ➔ Delivery status ➔ Typing ➔ Online status ➔ Pagination ➔ Offline send ➔ Delete chat ➔ Blacklist user ➔ Different types of chats ➔ Search ➔ Chat with Lalafo ➔ Automate response ➔ ... Features
68. Clean Architecture Dependency rule
69. Architecture
70. MVP
71. MVP
72. MVP
73. MVP
74. MVP & State Machine
75. RxRedux
76. StateMachine Actions //Input Actions sealed class Action { object LoadNextPageAction : Action() data class ErrorLoadingPageAction(val error: Throwable, val page: Int) : Action() data class PageLoadedAction(val itemsLoaded:List<GithubRepository>, val page: Int) : Action() data class StartLoadingNextPage(val page: Int) : Action() }
77. StateMachine States sealed class State { object LoadingFirstPageState : State() data class ErrorLoadingFirstPageState(val errorMessage: String) :State() data class ShowContentState(val items: List<GithubRepository>, val page: Int) : State() }
78. StateMachine Setup class PaginationStateMachine @Inject constructor( private val githubOperations: GithubOperatinos) { val input: PublishSubject<Action> = PublishSubject.create() val state: Observable<State> = input .reduxStore( initialState = State.LoadingFirstPageState, sideEffects = listOf( ::loadFirstPageSideEffect, ::loadNextPageSideEffect, ::showAndHideLoadingErrorSideEffect ), reducer = ::reducer )
79. StateMachine Side Effect private fun loadFirstPageSideEffect(actions: Observable<Action>, state: StateAccessor<State>): Observable<Action>{ return actions.ofType(Action.LoadFirstPageAction::class.java) .filter { state() !is ContainsItems } // If first page was loaded, do nothing .switchMap { val state = state() val nextPage = (if (state is ContainsItems) state.page else 0) + 1 githubOperations.loadRepositories(nextPage) .map<Action> { result -> PageLoadedAction(itemsLoaded = result.items, page = nextPage) } .onErrorReturn { error -> ErrorLoadingPageAction(error, nextPage) } .startWith(StartLoadingNextPage(nextPage)) } }
80. StateMachine Reducer //Takes Actions and the current state to calculate the new state. private fun reducer(state: State, action: Action): State { return when (action) { is StartLoadingNextPage -> State.LoadingFirstPageState is PageLoadedAction -> State.ShowContentState(items = action.items, page = action.page) is ErrorLoadingPageAction -> State.ErrorLoadingFirstPageState(action.error.localizedMessage) } }
81. Displaying state open fun render(state: PaginationStateMachine.State) = when (state) { PaginationStateMachine.State.LoadingFirstPageState -> { recyclerView.gone() loading.visible() error.gone() } is PaginationStateMachine.State.ShowContentState -> { showRecyclerView(items = state.items, showLoadingNext = false) } is PaginationStateMachine.State.ErrorLoadingFirstPageState -> { recyclerView.gone() loading.gone() error.visible() snackBar?.dismiss() } Compose Dreams
82. Performance matters
83. DistinctUntilChanged val state: Observable<State> = input .reduxStore( initialState = State.LoadingFirstPageState, sideEffects = listOf( ::loadFirstPageSideEffect, ::loadNextPageSideEffect, ::showAndHideLoadingErrorSideEffect ), reducer = ::reducer ) .distinctUntilChanged()
84. Flat view hierarchy
85. Flat view hierarchy Drawable Canvas Drawable android.text.Layout android.text.Layout
86. Flat view hierarchy
87. Startup Time public class App extends MultiDexApplication { … @Override public void onCreate() { super.onCreate(); initWhenIdle(); } private void initWhenIdle() { Looper.myQueue().addIdleHandler(() -> { appComponent.socketMessageHandler().start(); return false; }); } }
89. WEB client Business needs
90. Resources
93. Design for flexibility
94. Cost of change
95. Learnings ➔ ➔ ➔ ➔
96. Guided Q&A
97. Rakhimov Andrii andrii.rakhimov@gmail.com https://github.com/ar-g