The document discusses SwiftUI 2 architecture for data-driven applications, highlighting components such as BookshelfView, BookEditView, and Firestore integration for managing book data. It presents binding solutions, observable objects, and Firebase for authentication, monitoring, and data handling. Additionally, it covers application lifecycle management in SwiftUI 2 without AppDelegate, using newer features like StateObject and UIApplicationDelegateAdaptor.

1. Peter Friese | Firebase Developer Advocate | @pete
rf
riese
 +
Firebase for Apple Developers

2. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

3. Architecture
For Data-Driven Apps
Photo by Lance Anderson on Unsplash

4. #one-book-a-week-challenge

6. Drill-down navigation
Three-column layout (iPad / Mac)
Single source of truth
Driving factors
UI always in sync

7. UI always in sync

8. BookShelfView
BookEditView
BookDetailsView
BookRowView
Source of Truth
books: [Book]
@ObservableObject
@Binding
Book
Book
Book

9. Challenge #1
This needs to be a binding
But this isn’t a list of bindings

10. struct BookShelfView: View {
@Binding var bookShelf: BookShelf
var body: some View {
List {
ForEach(Array(bookShelf.books.enumerated()), id: .element.id) { index, item in
BookRowView(book: $bookShelf.books[index])
}
.onDelete { indexSet in
bookShelf.books.remove(atOffsets: indexSet)
}
}
.navigationTitle(bookShelf.title)
}
}
Solution #1: iterate over enumerated items
🤔

11. struct BookShelfView: View {
@Binding var bookShelf: BookShelf
var body: some View {
List {
ForEach($bookShelf.books) { $book in
BookRowView(book: $book)
}
.onDelete { indexSet in
bookShelf.books.remove(atOffsets: indexSet)
}
}
.navigationTitle(bookShelf.title)
}
}
Solution #1: use list bindings
Everything is now bindable

12. Learn more
h
tt
ps://pete
rf
riese.dev/swi
ft
ui-list-item-bindings-behind-the-scenes/

13. How to update only
when the user commits?
Challenge #2

14. struct BookEditView: View {
@Binding var book: Book
@ObservedObject var bookEditViewModel: BookEditViewModel
init(book: Binding<Book>) {
self._book = book
self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue)
}
var body: some View {
TextField("Book title", text: $bookEditViewModel.book.title)
}
func save() {
self.book = bookEditViewModel.book
dismiss()
}
}
Solution 2: use inner @ObservableObject

15. struct BookEditView: View {
@Binding var book: Book
@ObservedObject var bookEditViewModel: BookEditViewModel
init(book: Binding<Book>) {
self._book = book
self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue)
}
var body: some View {
TextField("Book title", text: $bookEditViewModel.book.title)
}
func save() {
self.book = bookEditViewModel.book
dismiss()
}
}
Solution 2: use inner @ObservableObject

16. struct BookEditView: View {
@Binding var book: Book
@ObservedObject var bookEditViewModel: BookEditViewModel
init(book: Binding<Book>) {
self._book = book
self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue)
}
var body: some View {
TextField("Book title", text: $bookEditViewModel.book.title)
}
func save() {
self.book = bookEditViewModel.book
dismiss()
}
}
Solution 2: use inner @ObservableObject

17. struct BookEditView: View {
@Binding var book: Book
@ObservedObject var bookEditViewModel: BookEditViewModel
init(book: Binding<Book>) {
self._book = book
self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue)
}
var body: some View {
TextField("Book title", text: $bookEditViewModel.book.title)
}
func save() {
self.book = bookEditViewModel.book
dismiss()
}
}
Solution 2: use inner @ObservableObject

18. Solution 2

19. class BookEditViewModel: ObservableObject {
@Published var book: Book
@Published var isISBNValid: Bool = true
init(book: Book) {
self.book = book
self.$book
.map { checkISBN(isbn: $0.isbn) }
.assign(to: &$isISBNValid)
}
}
Solution 2: use inner @ObservableObject
Bonus: use Combine to
perform validation

20. Learn more about
Building SwiftUI Components
h
tt
ps://www.youtube.com/c/pete
rf
riese

21. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

23. Run with confidence Engage users
Develop apps faster

24. Run with confidence
Crashlytics
Performance
Monitoring
Test Lab
App Distribution
Engage users
Analytics
Predictions
Cloud
Messaging
Remote
Config
A/B Testing
Dynamic
Links
In-app
Messaging
Develop apps faster
Auth
Cloud
Functions
Cloud
Firestore
Hosting
ML Kit
Realtime
Database
Cloud
Storage
bit.ly/what-is-firebase
Extensions
Machine
Learning

28. #protip: Put it
beneath Asset.xcasset

29. Don’t forget to add
to all the targets!

30. Swift Package Manager
now officially supported!
h
tt
ps://github.com/
fi
rebase/
fi
rebase-ios-sdk

31. 🤔

32. Application Lifecycle
SwiftUI 2
Photo by Thor Alvis on Unsplash

33. SwiftUI 2: No more AppDelegate!
import SwiftUI
@main
struct BookShelfApp: App {
@StateObject var store = BookShelfStore(shelves: BookShelf.samples)
var body: some Scene {
WindowGroup {
NavigationView {
BookShelvesView(store: store)
Text("Select a shelf to see its books")
Text("Select a book to see its details")
}
}
}
}

34. SwiftUI 2: No more AppDelegate!
import SwiftUI
@main
struct BookShelfApp: App {
@StateObject var store = BookShelfStore(shelves: BookShelf.samples)
var body: some Scene {
WindowGroup {
NavigationView {
BookShelvesView(store: store)
Text("Select a shelf to see its books")
Text("Select a book to see its details")
}
}
}
}

35. Solution 1: use initialiser
import SwiftUI
@main
struct BookShelfApp: App {
@StateObject var store = BookShelfStore(shelves: BookShelf.samples)
var body: some Scene {
WindowGroup {
NavigationView {
BookShelvesView(store: store)
Text("Select a shelf to see its books")
Text("Select a book to see its details")
}

36. Solution 1: use initialiser
import SwiftUI
@main
struct BookShelfApp: App {
@StateObject var store = BookShelfStore(shelves: BookShelf.samples)
var body: some Scene {
WindowGroup {
NavigationView {
BookShelvesView(store: store)
Text("Select a shelf to see its books")
Text("Select a book to see its details")
}
init() {
FirebaseApp.configure()
}

37. Solution 2: use UIApplicationDelegateAdaptor
import SwiftUI
import Firebase
class AppDelegate: NSObject, UIApplicationDelegate {
func application(_ application: UIApplication,
didFinishLaunchingWithOptions
launchOptions:
[UIApplication.LaunchOptionsKey : Any]? = nil)
-
>
Bool {
FirebaseApp.configure()
return true
}
}
@main
struct BookShelfApp: App {
@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

38. Solution 2: use UIApplicationDelegateAdaptor
import SwiftUI
import Firebase
class AppDelegate: NSObject, UIApplicationDelegate {
func application(_ application: UIApplication,
didFinishLaunchingWithOptions
launchOptions:
[UIApplication.LaunchOptionsKey : Any]? = nil)
-
>
Bool {
FirebaseApp.configure()
return true
}
}
@main
struct BookShelfApp: App {
@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

39. Solution 2: use UIApplicationDelegateAdaptor
import SwiftUI
import Firebase
class AppDelegate: NSObject, UIApplicationDelegate {
func application(_ application: UIApplication,
didFinishLaunchingWithOptions
launchOptions:
[UIApplication.LaunchOptionsKey : Any]? = nil)
-
>
Bool {
FirebaseApp.configure()
return true
}
}
@main
struct BookShelfApp: App {
@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

40. Solution 2: use UIApplicationDelegateAdaptor
import SwiftUI
import Firebase
class AppDelegate: NSObject, UIApplicationDelegate {
func application(_ application: UIApplication,
didFinishLaunchingWithOptions
launchOptions:
[UIApplication.LaunchOptionsKey : Any]? = nil)
-
>
Bool {
FirebaseApp.configure()
return true
}
}
@main
struct BookShelfApp: App {
@UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

41. Watch the scene phase
Handle deep links
Continue user activities
Do more with the new life cycle

42. Watch the scene phase
Handle deep links
Continue user activities
Learn more
pete
rf
riese.dev/ultimate-guide-to-swi
ft
ui2-application-lifecycle/

43. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

44. Firestore

47. One-Time Fetches
Offline Mode
Effortless Syncing

48. bird_type:
airspeed:
coconut_capacity:
isNative:
icon:
vector:
distances_traveled:
"swallow"
42.733
0.62
false
<binary data>
{ x: 36.4255,
y: 25.1442,
z: 18.8816 }
[42, 39, 12, 42]
Document

49. Collection
Sub-Collection

50. Top level
collections
“books” collection a single book document

51. struct Book: Identifiable {
var id = UUID().uuidString
var shelfId: String?
var userId: String?
var title: String
var author: String
var isbn: String
var pages: Int
var isRead: Bool = false
var coverEditionKey: String?
}
Data Model

52. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

53. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

54. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

55. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

56. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

57. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

58. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
Can we do better?

59. (Yes, we can)

60. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
if let document = document {
let id = document.documentID
let data = document.data()
let title = data?["title"] as? String
?
?
""
let numberOfPages = data?["numberOfPages"] as? Int
?
?
0
let author = data?["author"] as? String
?
?
""
self.book = Book(id:id, title: title,
numberOfPages: numberOfPages, author: author)
}
}
}
}
Fetching a document from Firestore

61. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
}
}
}
Mapping data using Codable
if let document = document {
do {
self.book = try document.data(as: Book.self)
}
catch {
print(error)
}
}

62. func fetchBook(documentId: String) {
let docRef = Firestore.firestore().collection("books").document(documentId)
docRef.getDocument { document, error in
if let error = error as NSError? {
print("Error getting document: (error.localizedDescription)")
} else {
}
}
}
Mapping data using Codable
if let document = document {
do {
self.book = try document.data(as: Book.self)
}
catch {
print(error)
}
}

63. BookShelfView
BookEditView
BookDetailsView
BookRowView
Source of Truth
books: [Book]
@ObservableObject
@Binding
Book
Book
Book
Review: Architecture

64. BookShelfView
BookDetailsView
BookRowView
Source of Truth
books: [Book]
@ObservableObject
@Binding
Book
Book
Review: Architecture
Snapshot Listener

65. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

66. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

67. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

68. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

69. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

70. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

71. class BookStore: ObservableObject {
var db = Firestore.firestore()
private var listenerRegistration: ListenerRegistration?
@Published var books = [Book]()
func subscribe() {
listenerRegistration = db.collection("books")
.addSnapshotListener { [weak self] (querySnapshot, error) in
guard let documents = querySnapshot
?
.
documents else { return }
self
?
.
books = documents.compactMap { queryDocumentSnapshot in
let result = Result { try queryDocumentSnapshot.data(as: Book.self) }
switch result {
case .success(let book):
if let book = book {
return book
Fetching a collection of documents

73. Learn more
h
tt
ps://pete
rf
riese.dev/
fi
restore-codable-the-comprehensive-guide/

74. import Foundation
import Combine
import Firebase
import FirebaseFirestoreSwift
import os
class BookStore: ObservableObject {
/
/
MARK: - Dependencies
var db = Firestore.firestore()
/
/
MARK: - Publishers
@Published var user: User?
@Published var books = [Book]()
/
/
MARK: - Private attributes
@Published private var userId: String = "unknown"
private var listenerRegistration: ListenerRegistration?
private var cancellables = Set<AnyCancellable>()
Fetching a collection of documents

75. /
/
A Book value could not be initialized from the DocumentSnapshot.
switch error {
case DecodingError.typeMismatch(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.valueNotFound(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.keyNotFound(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.dataCorrupted(let key):
self
?
.
logger.debug("(error.localizedDescription):
(key.debugDescription)")
default:
self
?
.
logger.debug("Error decoding document:
(error.localizedDescription)")
}
return nil
}
}
}
}
Fetching a collection of documents

76. /
/
A Book value could not be initialized from the DocumentSnapshot.
switch error {
case DecodingError.typeMismatch(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.valueNotFound(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.keyNotFound(_, let context):
self
?
.
logger.debug("(error.localizedDescription):
(context.debugDescription)")
case DecodingError.dataCorrupted(let key):
self
?
.
logger.debug("(error.localizedDescription):
(key.debugDescription)")
default:
self
?
.
logger.debug("Error decoding document:
(error.localizedDescription)")
}
return nil
}
}
}
}
Fetching a collection of documents
about 100 lines of code

77. struct BookShelfView: View {
@FirestoreQuery(
collectionPath: "books",
predicates: [
.where("userId", isEqualTo: userId),
]
) var books: Result<[Book], Error>
@State var userId = "F18EBA5E"
var body: some View {
List(books) { book in
Text(book.title)
}
}
}
Firestore Property Wrapper Firebase 8.9.0
@FloWritesCode
@mo
rt
enditlevsen
Thanks to

78. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

79. Authentication
Photo by Conve
rt
Kit on Unsplash

80. Authentication
Photo by Eduardo Soares on Unsplash

81. Authentication
Photo by Victor Freitas on Unsplash

82. 

83. Sign in the user
Update the data model
Secure users’ data
How to implement
Firebase Authentication?

84. Anonymous Authentication
“Guest” accounts, rather

85. func signIn() {
registerStateListener()
if Auth.auth().currentUser
=
=
nil {
Auth.auth().signInAnonymously()
}
}
Anonymous Authentication

87. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple

88. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple

89. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple

90. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple

91. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple
Firebase SDK

92. SignInWithAppleButton(
onRequest: {
.
.
.
},
onCompletion: { result in
.
.
.
let appleIDToken = appleIDCredential.identityToken
let idTokenString = String(data: appleIDToken, encoding: .utf8)
let credential = OAuthProvider.credential(withProviderID: “apple.com",
idToken: idTokenString,
rawNonce: nonce)
Auth.auth().signIn(with: credential) { (authResult, error) in
if (error
!
=
nil) {
.
.
.
}
print(“User signed in")
dismiss()
}
}
).frame(width: 280, height: 45, alignment: .center)
Sign in with Apple
Firebase SDK

93. All books are stored in one single collection
Which user do
they belong to?

94. let query = db.collection("books")
.whereField("userId",
isEqualTo: self.userId)
query
.addSnapshotListener { [weak self] (querySnapsho
guard let documents = querySnapshot
?
.
documents els
Signed in user

95. rules_version = '2';
service cloud.firestore {
match /databases/{database}/documents {
match /{document=**} {
allow create: if request.auth
!
=
null;
allow read, update, delete: if request.auth
!
=
null
&
&
resource.data.userId
=
=
request.auth.uid;
}
}
}
Security Rules
Only signed-in users can
create new documents
Only owners may read and
modify a document

96. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

97. Combine

98. auth
?
.
signInAnonymously()
let user = auth
?
.
currentUser
print("User signed in with user ID: (user
?
.
uid)")
This might be nil

99. auth
?
.
signInAnonymously()
let user = auth
?
.
currentUser
print("User signed in with user ID: (user
?
.
uid)")
auth
?
.
signInAnonymously { result, error in
guard let result = result else {
return
}
print("User signed in with user ID: (result.user.uid)")
}
Do this instead

100. auth
.
.
.
auth
?
.
signInAnonymously()
.map{ $0.user }
.replaceError(with: nil)
.assign(to: &$user)
Even better

101. Launching with Firebase 8.9.0
h
tt
ps://github.com/
fi
rebase/
fi
rebase-ios-sdk/projects/3

102. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

103. async/await
Photo by Stephen H on Unsplash

104. extension ArticleAnalyser {
func process(url: String, completion: @escaping (Article)
-
>
Void) {
self.fetchArticle(from: url) { result in
switch result {
case .failure(let error):
print(error.localizedDescription)
case .success(let html):
self.extractTitle(from: html) { result in
switch result {
case .failure(let error):
print(error.localizedDescription)
case .success(let title):
self.extractText(from: html) { result in
switch result {
case .failure(let error):
print(error.localizedDescription)
case .success(let text):
self.extractImage(from: url) { result in
Problem: Callback Pyramid of Doom

105. extension AsyncArticleAnalyser {
func process(url: String) async throws
-
>
Article {
let htmlText = try await fetchArticle(from: url)
let text = try await extractText(from: htmlText)
let title = try await extractTitle(from: htmlText)
let imageUrl = try await extractImage(from: url)
let tags = await inferTags(from: text)
return Article(url: url,
title: title,
tags: tags,
imageUrlString: imageUrl)
}
}
Solution: Use async/await
Swift 5.5

106. func fetchArticle(from url: String) async throws
-
>
String {
guard let url = URL(string: url) else { throw AnalyserError.badURL }
return try await withUnsafeThrowingContinuation { continuation in
URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in
guard let localUrl = localUrl else {
continuation.resume(throwing: AnalyserError.badURL)
return
}
if let htmlText = try? String(contentsOf: localUrl) {
continuation.resume(returning: htmlText)
}
}
.resume()
}
}
Solution: Use async/await
Swift 5.5

107. func fetchArticle(from url: String) async throws
-
>
String {
guard let url = URL(string: url) else { throw AnalyserError.badURL }
return try await withUnsafeThrowingContinuation { continuation in
URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in
guard let localUrl = localUrl else {
continuation.resume(throwing: AnalyserError.badURL)
return
}
if let htmlText = try? String(contentsOf: localUrl) {
continuation.resume(returning: htmlText)
}
}
.resume()
}
}
Solution: Use async/await
Swift 5.5

108. func fetchArticle(from url: String) async throws
-
>
String {
guard let url = URL(string: url) else { throw AnalyserError.badURL }
return try await withUnsafeThrowingContinuation { continuation in
URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in
guard let localUrl = localUrl else {
continuation.resume(throwing: AnalyserError.badURL)
return
}
if let htmlText = try? String(contentsOf: localUrl) {
continuation.resume(returning: htmlText)
}
}
.resume()
}
}
Solution: Use async/await
Swift 5.5

109. func fetchArticle(from url: String) async throws
-
>
String {
guard let url = URL(string: url) else { throw AnalyserError.badURL }
return try await withUnsafeThrowingContinuation { continuation in
URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in
guard let localUrl = localUrl else {
continuation.resume(throwing: AnalyserError.badURL)
return
}
if let htmlText = try? String(contentsOf: localUrl) {
continuation.resume(returning: htmlText)
}
}
.resume()
}
}
Solution: Use async/await
Swift 5.5

110. auth
?
.
signInAnonymously { result, error in
guard let result = result else {
return
}
print("User signed in with user ID: (result.user.uid)")
}
do {
let result = try await Auth.auth().signIn(withEmail: email, password: password)
print("User signed in with user ID: (result.user.uid)")
}
catch {
print(error)
}
Works with Firebase, too!
Callback-style

111. Learn more
h
tt
ps://pete
rf
riese.dev/async-await-in-swi
f
h
tt
ps://www.youtube.com/watch?v=sEKw2BMcQtQ

112. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

113. Architecture Swi
ft
UI 2 Life Cycle
Firebase Firestore Authentication Combine async/await Completion block

114. Register now - it’s free!
h
tt
ps://
fi
rebase.google.com/summit

115. Thanks!
Peter Friese
h
tt
p://pete
rf
riese.dev
@pete
rf
riese
youtube.com/c/PeterFriese/
Follow me
h
tt
ps://github.com/pete
rf
riese/BookShelf
Code

116. Credits
fi
nish by Megan Chown from the Noun Project
Time by Nikita Kozin from the Noun Project
pipe by Komkrit Noenpoempisut from the Noun Project
Passpo
rt
by ProSymbols from the Noun Project
spiral by Alexander Skowalsky from the Noun Project
Architecture by Ervin Bolat from the Noun Project
Firebase logos cou
rt
esy h
tt
ps://
fi
rebase.google.com/brand-guidelines
Firebase logos cou
rt
esy h
tt
ps://
fi
rebase.google.com/brand-guidelines
Thanks!
Hea
rt
by Roman from the Noun Project

117. The End.