Simplifying Login with Swift Enums

Apps that support only one authentication method can often get one-star reviews. This is because on-boarding users isn't just about getting them to tap the login button. It's about building trust, and trust is established through options - Just adding Facebook or Google login isn't going cut it.

Unless your app deeply integrates with the provider there's no excuse not to support multiple authentication methods, but supporting multiple methods brings multiple complexities.

Learn how to simplify the process using classic patterns like delegation and view controller subclassing. By the end of the talk you'll have everything you need to building a trustworthy authentication flow.

Transcript

1. Building Trust through Authentication David East | @_davideast Dev Advocate | @Firebase
2. Simplifying Login with Enums
3. It’s all about the Enums, baby
4. Storytime
6. Etch
7. wanted to feature them
9. 5-star review time!
10. Reviews started good
11. Then things got a little rough
14. Etch required Facebook login for simplicity, not data.
15. Overly critical, yet enlightening review
16. Build trust by providing options
17. Overcast
18. Nearly 7,000 ratings
19. Etch went to multiple options
20. Multiple options in Swift
21. Enums
22. Enums enum LoginProvider { case Facebook case Email case Google case Twitter } Not defaulted to 0,1,2,3. Each is a fully-fledged value with an explicit type of LoginProvider.
23. In Swift, Enums are first-class types
24. The four stages of learning the awesomeness of Enums
25. Stage 1 - Raw Values
26. enum LoginProvider: String { case Facebook = "facebook" case Email = "email" case Google = "google" case Twitter = "twitter" } let provider = LoginProvider.init(rawValue: "email")
27. Stage 2 - Associated Values
28. enum LoginProvider { case Facebook case Email: (String, String) case Google case Twitter } let provider = LoginProvider.Email("bob@bob.com", "pass")
29. Associated Values can be of any-type
30. struct LoginUser { let email: String let password: String func isValid() -> Bool { return email != "" && password != "" } }
31. enum LoginProvider { case Facebook case Email: (LoginUser) case Google case Twitter } let user = LoginUser(email: "bob@bob.com", pass: "pass") let provider = LoginProvider.Email(user)
32. switch provider { case let .Email(user) // login! break }
33. Stage 3 - case where
34. switch provider { case let .Email(user) where user.isValid(): // login! break case let .Email(user) where !user.isValid(): // don’t login! break }
35. Stage 4 - Functions
36. enum LoginProvider { func login() { switch self { case let .Email(user) where user.isValid(): // login! break } } }
37. let provider = LoginProvider.Facebook provider.login() // How do we surface the login to the View Controller?
38. Login is asynchronous
39. Multiple logins == Multiple async flows
40. Social Login SDKs are like snowflakes, no two are the same.
41. Login SDKs Facebook - Async call to login, async call for user info Google - Requires two delegates Twitter - Async call to get accounts, async call to login Email & Password - Totally custom
42. How do we simplify?
43. Define your own flow
44. Delegate Not as Swifty
45. protocol LoginProviderDelegate { func loginProvider(loginProvider: LoginProvider, didSucceed user: User) func loginProvider(loginProvider: LoginProvider, didError error: NSError) }
46. func login(delegate: LoginProviderDelegate) { switch self { case let .Email(loginUser) where loginUser.isValid(): // make server call to login LoginProvider.emailHelper.login(user) { (user, error) in delegate.loginProvider(self, didSucceed: user) } } }
47. class ViewController: UIViewController, LoginProviderDelegate { let provider = LoginProvider.Facebook @IBAction func loginDidTouch() { provider.login(self) } func loginProvider(loginProvider: LoginProvider, didSucceed: User) { print(user) }
48. Code Demo
49. Gain trust through login options
50. Simplify login options through enums
51. David East | @_davideast