Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (13)
Similar to Medium TechTalk — iOS
Similar to Medium TechTalk — iOS (20)
Recently uploaded
Recently uploaded (20)
Medium TechTalk — iOS
- 4. How might we create a simple and intuitive mobile consumption experience for Medium?
- 6. How might we create a simple and intuitive mobile consumption experience for Medium?
- 7. How might we create a delightful, simple and intuitive mobile consumption experience for Medium?
- 13. History stack Future stack Cover Flow
- 14. <html>?
- 18. • 60 FPS • Memory • Parallax UIKit & TextKit
- 19. { "content": { ... "bodyModel": { "elements": <Elements>, "sections": <Sections> }, ... }, }
- 20. { "name": "8419", "type": 1, "text": "...song Walking in LA?", "markups": [ { "type": 3, "start": 300, "end": 315, "href": "https://somewhere.com", "title": "", "rel": "" } ] }
- 21. { "name": "24cc", "type": 4, "text": "", "markups": [], "layout": 1, "metadata": { "id": "1*WwSQ20QNvf-WovuMLLslEA.jpeg", "originalWidth": 453, "originalHeight": 301 } }
- 23. { "name": "7b28", "startIndex": 31, "backgroundImage": { "id": "1*DhgXe8j0YqltMNM6-pRy6Q.jpeg", "originalWidth": 1920, "originalHeight": 1200 }, "textLayout": 2, "imageLayout": 2 }
- 24. CoverFlowView
- 31. CoverFlowView PostView SectionView SectionContentView ElementElementElement SectionImageView Element
- 32. CoverFlowView PostView SectionView SectionContentView ElementElementElement SectionImageView Element
- 38. CoverFlowView PostView SectionView SectionImageView SectionContentView ElementElement Sect Section
- 39. CoverFlowView PostView View ageView ntentView lement SectionView SectionImageView SectionC Elemen
- 45. Shapes & things Building the data layer of the Medium iOS app ! ! Elizabeth Ford @infraredflower
- 49. User’s name Bio List of stories
- 50. • How will we deal with the possibility of API changes? • especially since the app will be long-lived • How do we minimize the number of requests from the iOS app to the server? • How can we avoid making separate API routes for the iOS app (and every client thereafter)? Questions…
- 51. Clearly bad ideas • Make multiple requests to display one Post, User, or Collection • Make new iOS routes with exactly what we need • Only save full objects
- 52. Clearly bad ideas • Save partial objects and if we need a full object, just check to see if all the fields are set in the object in the cache • Is the field supposed to be “” or was it never set?
- 53. Speaking of which… • How should we deal with merging two objects?
- 54. • Merging a full post and a partial post Example
- 55. Shapes!
- 56. Shapes!
- 57. Saving objects
- 58. Merging objects
- 59. Complexity hidden by data layer • merges objects • determines when to make network requests
- 60. Complexity hidden by data layer
- 61. What about dealing with a changing API? • explicit definitions for the resources returned by API endpoints • tests based on these definitions
- 62. Possible areas for improvement • one service to return any shape (instead of a separate data service for each type of object) • autogenerate shape definitions from protocol buffers (on both server and client)
- 63. • easy to add features on the iOS side • easy to make changes on the server side without breaking the iOS client • minimize # of server requests Shapes!
- 65. Meet the Singletons Jimmy O’Neill Engineer, Medium @jmyonl
- 66. + (id)sharedResource { static id _instance; static dispatch_once_t onceToken; ! dispatch_once(&onceToken, ^{ _instance = [[Resource alloc] init]; }); ! return _instance; }
- 67. A singleton restricts the instantiation of a class to one object. They are often lazily instantiated. They can be accessed globally by any module of a program.
- 69. Since singletons are so commonplace in CocoaTouch, many developers overuse them.
- 70. A lot of this: Singletons are bad!! ! Not a lot of this: Singletons can be bad because ____. Here’s a real example!
- 71. ! ! ! I’m going to focus on this: Singletons can be bad because ____. Here’s a real example!
- 73. - (AuthCredential *)mediumAuthCredential; ! - (void)saveMediumAuthCredential:(AuthCredential *)credential; AuthCredentialDataService Keychain AuthCredentialDataService
- 74. - (void)fetch:(NetRequest *)request completion:(void (^)(NetResponse *, NSError *))completion; Net AuthCredentialDataService NetNet
- 75. - (void)fetchPostById:(NSString *)postId completion:(void(^)(Post *post, NSError *error))completion; PostService Net AuthCredentialDataService PostService
- 76. - (void)fetchPostViewDataWithPostId:(NSString *)postId completion:(void(^)(Post *post, PostViewModel *postViewModel, PostUserData *postUserData, NSError *error))callback; PostViewService PostService Net AuthCredentialDataService PostViewService
- 80. Time dependence isn’t an issue until the underlying data starts changing. PostViewController PostViewService PostService Net AuthCredentialDataServiceAuthCredentialDataService PostViewController
- 81. If your app supports sign out, the underlying authentication data is changing. PostViewController PostViewService PostService Net AuthCredentialDataServiceAuthCredentialDataService PostViewController
- 82. What problems does time dependence cause? - Functional impurity - Leaky abstraction - Background task failures - Difficult to test PostViewController PostViewService PostService Net AuthCredentialDataServiceAuthCredentialDataService PostViewController
- 83. Example.
- 89. 1. User bookmark action is queued PostViewController PostViewService PostService Net AuthCredentialDataService Logged in dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 90. 1. User bookmark action is queued 2. User signs out PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 91. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 92. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 93. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 94. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 95. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued 4. Bookmark request 401s PostViewController PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 96. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued 4. Bookmark request 401s 5. PostViewController is cleaned up PostViewService PostService Net AuthCredentialDataService Logged out LoginViewController dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId]; });
- 97. How do we fix this?
- 98. Option 1: YOLO Advantages! - Very little work - No testing needed - Funny later in your career Disadvantages! - Horrible UX - Async bookmark operation still fails - (void)logOut { // nuke everything exit(0); }
- 99. Option 2: Embrace time dependence Advantages! - Doesn’t require refactoring Disadvantages! - Requires global knowledge of all the apps components - Affects other, disjunct service consumers - Difficult to test - Async bookmark operation still fails - (void)logOut { // Synchronously wipe all the user-dependent data [[Services authCredentialDataService] wipeData]; // … ! // Reload UI with new global data [_appController reload]; }
- 100. Option 3: Dependency inject your user-dependent data - Eliminates time dependence in the service layer - Gracefully supports switching authentication contexts - Easy to test interfaces with a mock Session object - Async bookmark operation succeeds - (void)logOut { // Create an unauthenticated session Session *newSession = [Session loggedOutSession]; ! // Reload UI with logged out session [_appController loadSession:newSession]; }
- 101. @interface Session : NSObject ! - (instancetype)initWithAuth:(AuthCredential *)authCredential; ! @property (nonatomic, strong, readonly) NSString *sessionId; @property (nonatomic, strong, readonly) AuthCredential *authCredential; ! - (BOOL)isAuthenticated; ! @end The Session object directly models user-dependent state, and is injected into objects that need it.
- 102. - (void)fetch:(NetRequest *)request completion:(void (^)(NetResponse *, NSError *))completion; Net AuthCredentialDataService Net
- 104. Net Session - (void)fetch:(NetRequest *)request session:(Session *)session completion:(void (^)(NetResponse *, NSError *))completion; Net
- 105. PostService Net Session - (void)fetchPostById:(NSString *)postId session:(Session *)session completion:(void(^)(Post *post, NSError *error))completion; PostService
- 106. PostViewService PostService Session Net - (void)fetchPostViewDataWithPostId:(NSString *)postId session:(Session *)session completion:(void(^)(Post *post, PostViewModel *postViewModel, PostUserData *postUserData, NSError *error))callback; PostViewService
- 108. PostViewController
- 109. PostViewController
- 111. LoginViewController
- 112. 1. User bookmark action is queued PostViewService PostService Net PostViewController Logged in Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 113. 1. User bookmark action is queued 2. User signs out PostViewService PostService Net PostViewController Logged in Session LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 114. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewService PostService Net PostViewController Logged in Session LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 115. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewService PostService Net PostViewController Logged in Session LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 116. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued PostViewService PostService Net PostViewController Logged in Session LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 117. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued 4. Bookmark action succeeds PostViewService PostService Net PostViewController Logged in Session LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 118. 1. User bookmark action is queued 2. User signs out 3. Bookmark action is dequeued 4. Bookmark action succeeds 5. PostViewController and logged in Session are cleaned up PostViewService PostService Net LoginViewController Logged out Session dispatch_async(_backgroundQueue, ^{ [[Services postView] bookmark:_postId session:_session]; });
- 119. Think back to the original decision. Net AuthCredentialDataService Keychain Net
- 120. It appears innocent without context. Net AuthCredentialDataService Keychain Net
- 121. Let’s do our best to recognize! the larger context earlier. PostViewController PostViewService PostService Net AuthCredentialDataService Data dependence Time dependence AuthCredentialDataService PostViewController
- 122. Singletons are global state.
- 123. Singletons assume that the lifetime of the state they encapsulate is equal to the lifetime of the program.
- 124. Singletons are not evil.
- 125. But often, dependency injection is a sounder option.
- 127. Designing an iOS Distribution Pipeline Vinicius Baggio Fuentes
- 128. Delivery on the Web • Feature Toggle • Tracking and measuring • Rolling releases • Multiple deploys a day
- 129. Short deployment time is key
- 130. How can we do the same for apps?
- 131. Challenges • Pre-App Store distribution is complicated • Slow response time on App Store approvals
- 132. Fast release requirements • Over-the-air updates • Crash report system • Authorization server • Feature toggles • Versioning system • Distribution channels
- 133. OTA updates, crash reports and authorization • Crashlytics • TestFlight / Apple’s upcoming beta program • HockeyApp
- 134. Feature toggle • A/B Testing • Long running feature development • Emergencies
- 136. Feature toggle tools • GroundControl, SkyLab & related projects • Roll-your-own (not recommended)
- 141. master 640a0a5 build-1.3 638b3b7 03dc0b5 4aee8cd dde3123 bb24c74 build-1.3.0
- 142. master 640a0a5 build-1.3 638b3b7 03dc0b5 4aee8cd 04d773b dde3123 bb24c74 f1e48af build-1.3.1 build-1.3.0
- 143. master 640a0a5 build-1.3 build-1.4 638b3b7 03dc0b5 4aee8cd 04d773b dde3123 bb24c74 f1e48af build-1.3.1 f1e48af build-1.3.0 build-1.4.0
- 145. Distribution channels Developers Medium Staff On merge Version 1.4.90
- 146. Distribution channels Version 1.4.90 Developers Medium Staff Trusted testers On merge After a day
- 147. Distribution channels Version 1.4.90 Developers Medium Staff Trusted testers Beta testers On merge After a day After a week
- 148. Lessons Learned • Xcconfig files and -derivedDataPath compiler flag helps builds being deterministic • Plist manipulation in Python, nomad-cli tools (esp. Shenzhen, Cupertino)
- 149. Xcconfig example #include "base.xcconfig" #include "Servers/medium.xcconfig" #include "Build/config-debug.xcconfig" ! MEDIUM_DISTRIBUTION_CHANNEL = mediumStaff
- 150. Lessons Learned [2] • Make it easy for everyone to see which version of the app each group has • Easy visibility and communication on features of each of these groups • Automate everything, consider Jenkins CI over Xcode Bots
- 151. Thanks! • References: • www.nomad-cli.com • jenkins-ci.org • crashlytics.com • https://github.com/mattt/GroundControl • http://semver.org • hockeyapp.net • http://techcrunch.com/2014/06/02/ios-testflight/ Vinícius Baggio Fuentes vinny@medium.com @vinibaggio
- 152. Thanks for coming!