Realm Centered Design

RxSwift+RxRealm w/ RealmNotification

Transcript

1. yohei SUGIGAMI
   Realm Centered Design
   RxSwift+RxRealm w/ RealmNotification
   Sep. 29, 2016 @ SanSan
   Realm meetup #19
   

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2. Yohei SUGIGAMI
   ID susieyy
   TwitterˍGithub & Qiita
   

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3. γΰτͰίίϩΦυϧ
   Launch iPhone3G
   iOS Developer since mid 2008
   

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4. γΰτͰίίϩΦυϧ
   WWDC 2014
   Swift Developer since Day1
   

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5. γΰτͰίίϩΦυϧ
   Working in a Wantedly
   

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6. Our issues
   in iOS development
   

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7. Our issues in iOS development
   Complex
   
   

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8. Our issues in iOS development
   State and data
   management
   Complex
   

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9. Our issues in iOS development
   Asynchronous
   processing
   Complex
   

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10. Our issues in iOS development
    Massive delegate
    pattern
    Complex
    https://developer.apple.com/library/content/documentation/General/Conceptual/DevPedia-CocoaCore/MVC.html
    Apple MVC Apple MVC
    

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11. Reactive program paradigm
    Observable
    Asynchronous data streams
    Functional program paradigm
    No side effects function
    Immutable structure
    Higher-order functions
    Lambda expression, monads
    Asynchronous friendly
    Unidirectional Data Flow
    Single source of truth
    The approach avoids complicated to simplify
    Redux
    RxSwift
    Reactive
    Cocoa
    simplify
    

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12. Hoping between RxSwift and ReSwift
    Redux
    Rx ???
    w/ MVVM
    (RxSwift) (ReSwift)
    Unidirectional 

    Data Flow
    

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18. Approaching based on Rx with Realm
    Redux
    Rx Realm
    +
    w/ MVVM
    (RxSwift) (ReSwift)
    Unidirectional 

    Data Flow
    Unidirectional 

    Data Flow
    (RxRealm)
    

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19. Realm Centered Design
    View
    ViewModel
    Model
    Rx
    ( Local state )
    Store
    ( App state )
    Rx w/ MVVM
    

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20. Unidirectional Data Flow
    Transaction
    ( atomic )
    Notification
    Subscribe
    Realm Centered Design
    https://realm.io/news/unidirectional-data-flow-in-swift/
    

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21. Launch iPhone3G
    iOS Developer since mid 2008
    Key technologies
    Realm Notification
    RxRealm
    RxSwift w/ MVVM
    

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22. Launch iPhone3G
    iOS Developer since mid 2008
    Realm Notification
    Notifications section
    https://realm.io/docs/swift/latest/#notifications
    Collection Notifications, since ver 0.98
    https://realm.io/news/realm-objc-swift-0.98.0/
    Fine-grained change notifications, since ver 0.99
    https://realm.io/news/realm-objc-swift-0.99.0/
    

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23. Launch iPhone3G
    iOS Developer since mid 2008
    Do you know the Realm Notification?
    
    

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24. Launch iPhone3G
    iOS Developer since mid 2008
    You can be notified whenever a Realm,
    Results, List or LinkingObjects is updated by
    calling the addNotificationBlock method.
    a.k.a. Observe
    What Realm Notification
    

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25. Launch iPhone3G
    iOS Developer since mid 2008
    Realm Notifications
    Collection Notifications
    Fine-grained change
    Points
    

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26. Launch iPhone3G
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    Realm instances send out notifications to
    other instances on other threads every time a
    write transaction is committed:
    Realm Notifications
    

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27. Launch iPhone3G
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    Realm Notifications, e.g.
    

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28. Launch iPhone3G
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    Collection Notifications
    Notified of updates to query results or to
    specific objects.
    

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29. Launch iPhone3G
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    ( should keep a strong reference )
    Collection Notifications, e.g.
    

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30. Launch iPhone3G
    iOS Developer since mid 2008
    Fine-grained level changing
    This change parameter describes including the
    indices of objects that have been inserted, deleted, or
    modified since the last notification.
    

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31. Launch iPhone3G
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    notified indices with deltas
    Fine-grained change, e.g.
    

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32. Launch iPhone3G
    iOS Developer since mid 2008
    In the case of Core Data
    let notificationCenter = NSNotificationCenter.defaultCenter()
    notificationCenter.addObserver(self, selector: #selector(managedObjectContextDidChange:),
    name: NSManagedObjectContextObjectsDidChangeNotification,

    object: privateManagedObjectContext)
    Can not observe with filtering.
    

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33. Launch iPhone3G
    iOS Developer since mid 2008
    In the case of Core Data
    func managedObjectContextObjectsDidChange(notification: NSNotification) {
    guard let userInfo = notification.userInfo else { return }
    if let inserts = userInfo[NSInsertedObjectsKey] as? Set where inserts.count > 0 {
    }
    if let updates = userInfo[NSUpdatedObjectsKey] as? Set where updates.count > 0 {
    }
    if let deletes = userInfo[NSDeletedObjectsKey] as? Set where deletes.count > 0 {
    }
    }
    Received changed objects, instead of changed indices
    

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34. Launch iPhone3G
    iOS Developer since mid 2008
    Notified timing
    When notifications can’t be delivered instantly,
    multiple write transactions may be coalesced into a
    single notification.
    t
    Tx
    COMMIT
    Tx
    COMMIT
    Tx
    COMMIT
    Tx
    COMMIT
    Tx
    COMMIT
    t
    Notice Notice
    Write
    Notification
    

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35. Launch iPhone3G
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    It is also notified being monitored
    relation destination of the change of
    the Object.
    Observable relations ( linking objects )
    

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36. Launch iPhone3G
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    Observable relations ( linking objects )
    UserObject
    name
    avatar_url
    registered
    deleted_at
    profile
    ProfileObject
    company
    position
    working_histories
    academy_records
    emails
    EmailObject
    email
    Observe Change Change
    Notified
    
    

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37. Launch iPhone3G
    iOS Developer since mid 2008
    Model
    View
    B
    View
    A
    Notification
    Notification
    WriteTx
    Absolutely separation logic and views
    Singleton
    PreFetch
    BackgroundFetch
    

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38. Launch iPhone3G
    iOS Developer since mid 2008
    View
    A
    View
    B
    Notification
    WriteTx
    Absolutely separation logic and views
    

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39. e.g.
    WriteTx
    Notification
    Notification
    ➜ ➜
    

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40. Launch iPhone3G
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    RxSwift
    RxRealm
    x
    meets
    https://github.com/RxSwiftCommunity/RxRealm
    

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41. Launch iPhone3G
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    What RxRealm
    Rx wrapper for Realm's collection types.
    

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42. Launch iPhone3G
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    Observing collections
    Adds to Results, List, LinkingObjects and AnyRealmCollection
    these methods:
    - asObservable()
    - asObservableArray()
    - asObservableChangeset()
    - asObservableArrayChangeset()
    returning an Observable, RealmChangeset?>
    

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43. Launch iPhone3G
    iOS Developer since mid 2008
    try! Realm().objects(ContactRealm)
    .asObservableChangeset()
    .subscribeNext { [weak self] results, changeset in
    guard let tableView = self?.tableView else { return }
    self?.results = results
    if let changeset = changeset {
    tableView.beginUpdates()
    tableView.insertRowsAtIndexPaths(…, withRowAnimation: .Automatic)
    tableView.deleteRowsAtIndexPaths(…, withRowAnimation: .Automatic)
    tableView.reloadRowsAtIndexPaths(…, withRowAnimation: .Automatic)
    tableView.endUpdates()
    } else {
    tableView.reloadData()
    }
    }.addDisposableTo(disposeBag)
    e.g.
    

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44. - rx_add()
    - rx_delete()
    Write transactions
    // Simple Create
    [MessageRealm("hello"), MessageRealm("world")]
    .toObservable()
    .subscribe(Realm.rx_add())
    // With API
    let request = API.Endpoint.MessagesRequest().request()
    Session.rx_response(request)
    .subscribe(Realm.rx_add())
    

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45. B
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    RxSwift MVVM
    Realm Centered Design
    RxRealm
    

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46. Launch iPhone3G
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    View ViewModel
    View A
    Subscribe
    Holding
    - The state of a screen-specific (Requesting, etc)
    - The main data of a screen
    RxSwift w/ MVVM
    It is difficult to handle the screen
    cross-data.
    View B
    View C
    

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47. Launch iPhone3G
    iOS Developer since mid 2008
    View ViewModel
    Subscribe
    Singleton
    RxSwift w/ MVVM and Singleton
    Global ViewModel
    View A
    View B
    View C
    Holding
    - The state of a screen-specific (Requesting, etc)
    - The main data of a screen
    (Rx Variable)
    The state of cross over screens
    

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48. Launch iPhone3G
    iOS Developer since mid 2008
    View ViewModel Observable Store
    Subscribe
    The state of a screen-specific
    Singleton
    RxSwift+RxRealm w/
    MVVM
    (RxRealm)
    View A
    View B
    View C
    (Rx Variable)
    The main data of screens
    The state of cross over screens
    

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49. Conclusion
    Simple
    ( is not easy )
    Complex
    
    

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50. 5IBOLZPV
    

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