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async/awaitͷੑೳΛ
DartͱSwiftͱͷൺֱͰಡΈղ͘
iOSDC 2021
Tamappe
@tamapppe
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I N T R O D U C T I O N
Tamappe
ϞόΠϧΞϓϦΤϯδχΞ
2014-20193݄·ͰϑϦʔϥϯεͱͯ͠׆ಈ
20194݄ΑΓϨΞδϣϒʹϞόΠϧΞϓϦΤϯδχΞͱͯ͠ೖࣾ
झຯ: ϒϩάͷߋ৽ɺσΟζχʔ८Γ(ίϩφʹΑΓࣗॗ)
Qiita: https://qiita.com/tamappe
Blog: https://tamappe.com
Twitter: https://twitter.com/tamapppe
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גࣜձࣾϨΞδϣϒ
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ຊͷςʔϚ
async/await
SwiftͱDartͷൺֱ
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͖͔͚ͬ…
WWDC 2021Ͱasync/awaitൃද
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͖͔͚ͬ…
ɾfunctionͰ͑Δ
ɾError handling Ͱ͑Δ
ɾfor จ(Async sequences)Ͱ͑Δͷʁ
ɾgetterͰ͑ΔΜʁʁ
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ˎasync/awaitͲͷݴޠͰૉΒ͍͠Ͱ͢
SwiftͰͷasync/await
ΊͬͪΌੌ͍Μ
݁...
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Ajenda
1. async/await ൺֱ
2. SwiftͰͷasync/await
3. SwiftͰͷӨڹൣғ
4. DartͰͷasync/await
5. DartͰͷϝϦοτɾσϝϦοτ
6. ·ͱΊ
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async/await ൺֱ
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Swift Dart
Function ○ ○
Error handling ○ ○
Property(getter) ○ ×
Parameter × ○
Async sequences ○ ×
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async/await is …
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1.Simple
2.Easy
3.Safe
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SwiftͰͷasync/await
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SwiftͰͷasync/await
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Function
WWDC 2021 Meet async/await in Swift
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SwiftͰͷasync/await
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Function
func asyncFetchData() async throws -> Data {
let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")!
let request = URLRequest(url: url)
let (data, response) = try await URLSession.shared.data(for: request,
delegate: nil)
guard (response as? HTTPURLResponse)?.statusCode == 200 else {
throw NSError(domain: "error", code: -1, userInfo: nil)
}
return data
}
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SwiftͰͷasync/await
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Property (getter)
WWDC 2021 Meet async/await in Swift
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SwiftͰͷasync/await
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Property (getter)
extension UIImage {
var thumbnail: UIImage? {
get async {
let size = CGSize(width: 40, height: 40)
return await self.byPreparingThumbnail(ofSize: size)
}
}
}
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SwiftͰͷasync/await
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Async sequences (for loop)
WWDC 2021 Meet async/await in Swift
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SwiftͰͷasync/await
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sync to async
WWDC 2021 Meet async/await in Swift
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SwiftͰͷasync/await
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sync to async
func doSomething() {
async {
let data = try await asyncFetchData()
}
}
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SwiftͰͷӨڹൣғ
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SwiftͰͷӨڹൣғ
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1. ίʔϧόοΫ
- ίʔϧόοΫ(ωετ)ࠈ͔Βͷղ์
- weakSelf͔Βͷղ์
2. Thread
- actorʹΑΓMainActorͰϝΠϯεϨουͰ࣮ߦ
3. CoreData
- contextͰͷΓͱΓ
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SwiftͰͷӨڹൣғ (ίʔϧόοΫ)
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class SampleRequest: NSObject {
func fetchSomethingA(id: Int, compeltion: (Int) -> Void) { }
func fetchSomethingB(id: Int, compeltion: (Int) -> Void) { }
func fetchSomethingC(id: Int, compeltion: (Int) -> Void) { }
}
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SwiftͰͷӨڹൣғ (ίʔϧόοΫ)
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class SampleRequest: NSObject {
// தུ
func requestSomething() {
fetchSomethingA(id: 1, compeltion: { [weak self] a in
// ॲཧΛॻ͘
self?.fetchSomethingB(id: a, compeltion: { [weak self] b in
// ॲཧΛॻ͘
self?.fetchSomethingC(id: b, compeltion: { c in
// ॲཧΛॻ͘
})
})
})
}
}
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ίʔϧόοΫ is …
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not Simple
not Easy
not Safe
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SwiftͰͷӨڹൣғ (ίʔϧόοΫ)
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class SampleRequest: NSObject {
func fetchSomethingA(id: Int) async -> Int {
return 1
}
func fetchSomethingB(id: Int) async -> Int {
return 2
}
func fetchSomethingC(id: Int) async -> Int {
return 3
}
}
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SwiftͰͷӨڹൣғ (ίʔϧόοΫ)
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class SampleRequest: NSObject {
// தུ
func requestSomething() async {
let a = await fetchSomethingA(id: 1)
let b = await fetchSomethingB(id: a)
let c = await fetchSomethingC(id: b)
// ॲཧΛॻ͘
}
}
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SwiftͰͷӨڹൣғ (ίʔϧόοΫ)
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1.Simple
2.Easy
3.Safe
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SwiftͰͷӨڹൣғ (Thread)
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εϨουૢ࡞Ͳ͏ͳΔ͔
- UITableView
- UICollectionView
- Viewͷߋ৽ॲཧ
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SwiftͰͷӨڹൣғ (Thread)
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class SampleViewController: UIViewController {
@IBOutlet weak var collectionView: UICollectionView!
func update() {
// APIͰσʔλΛऔಘޙʹUIͷߋ৽
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
}
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SwiftͰͷӨڹൣғ (Thread)
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ɾactor
ɾMainActor
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SwiftͰͷӨڹൣғ (Thread)
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class SampleRequest: NSObject {
var number: Int = 0
// தུ
func requestSomething() async {
let a = await fetchSomethingA(id: 1)
let b = await fetchSomethingB(id: a)
let c = await fetchSomethingC(id: b)
// ॲཧΛॻ͘
Task.detached(priority: nil, operation: { @MainActor in
// @MainActor ͰϝΠϯεϨουͰߋ৽Ͱ͖Δʁ
self.number = c
})
}
}
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SwiftͰͷӨڹൣғ (CoreData)
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synchronous functions (ಉظॲཧ) asynchronous functions (ඇಉظॲཧ)
.performAndWait await perform
.perform await perform(.enqueued)
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SwiftͰͷӨڹൣғ (CoreData)
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func executePerform() {
let persistentContainer = NSPersistentContainer(name: "XXX")
let context = persistentContainer.newBackgroundContext()
context.perform {
// ॲཧ
context.perform {
// ॲཧ
context.perform {
// ॲཧ
}
try? context.save()
}
}
}
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SwiftͰͷӨڹൣғ (CoreData)
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func asyncExecutePerform() async {
let persistentContainer = NSPersistentContainer(name: "XXX")
let context = persistentContainer.newBackgroundContext()
await context.perform {
// ॲཧ
}
await context.perform {
// ॲཧ
try? context.save()
}
await context.perform {
// ॲཧ
}
}
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DartͰͷasync/await
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DartͰͷasync/await
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1. ؔʹasyncΛએݴ͢Δ
2. ݺͼग़࣌͠ʹawaitΛએݴ
3. ύϥϝʔλʔFutureܕ
ˎCombine.frameworkͷFutureͱ͍ۙ
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DartͰͷasync/await
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Example: synchronous functions (ಉظॲཧ)
String createOrderMessage() {
var order = fetchUserOrder();
return 'Your order is: $order';
}
Future fetchUserOrder() =>
Future.delayed(const Duration(seconds: 2), () => 'Large Latte',);
void main() {
print('Fetching user order...');
print(createOrderMessage());
}
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DartͰͷasync/await
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Future createOrderMessage() async {
var order = await fetchUserOrder();
return 'Your order is: $order';
}
Future fetchUserOrder() =>
Future.delayed(const Duration(seconds: 2), () => 'Large Latte',);
Future main() async {
print('Fetching user order...');
print(await createOrderMessage());
}
Example: asynchronous functions (ඇಉظॲཧ)
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DartͰͷasync/await
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https://dart.dev/codelabs/async-await
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DartͰͷasync/await (then ݺͼग़͠)
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Future hello() async {
var order = await fetchHello();
return order;
}
Future fetchHello() =>
Future.delayed(const Duration(seconds: 2), () => 'Hello world',);
main() async {
hello()
.then((value) {
// thenͰܨ͛Δ
print(value);
});
}
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DartͰͷasync/await (Error handling)
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main() async {
hello()
.then((value) {
// thenͰܨ͛Δ
print(value);
})
.catchError((error) {
// catchError Ͱܨ͛Δ
print(error);
});
}
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DartͰͷϝϦοτɾσϝϦοτ
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ϝϦοτ
ɾDartͷඪ४Ͱasync/await͕͑Δ
ɾFutureܕ͕͋Δ
ɾiOS ͷ݅ʹറΓ͕ͳ͍
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DartͰͷϝϦοτɾσϝϦοτ
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σϝϦοτ
ɾจ๏͕JavaϥΠΫͰݹ͍ॻ͖ํ
ɾenum͕SwiftΑΓॊೈʹॻ͚ͳ͍
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Dartͷenum (͓·͚)
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Swift Dart
Normal (Int Value) ○ ○
Iterating over Enumeration Cases ○ ×
Associated Values ○ ×
Implicitly Assigned Raw Values ○ ×
Recursive Enumerations ○ ×
https://docs.swift.org/swift-book/LanguageGuide/Enumerations.html
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Dartͷenum (͓·͚)
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// Value int
enum Type {
First,
Second,
Third,
Fourth
}
// Dartͷ֦ுؔ on ͱϥϕϦϯά͕ඞཁ
extension TypeExtension on Type {
String parseString() {
switch (this) {
case Type.First:
return "First";
case Type.Second:
return "Second";
case Type.Third:
return "Third";
case Type.Fourth:
return "Fourth";
}
}
}
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·ͱΊ
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Swift Dart
Function ○ ○
Error handling ○ ○
Property(getter) ○ ×
Parameter × ○
Async sequences ○ ×
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Ҿ༻ 1
Asynchronous programming
https://dart.dev/codelabs/async-await
Futures and error handling
https://dart.dev/guides/libraries/futures-error-handling
WWDC 2021 Meet async/await in Swift
https://developer.apple.com/videos/play/wwdc2021/10132
WWDC 2021 Meet AsyncSequence
https://developer.apple.com/videos/play/wwdc2021/10058
WWDC 2021 Use async/await with URLSession
https://developer.apple.com/videos/play/wwdc2021/10095
WWDC 2021 Bring CoreData concurrency to Swift and SwiftUI
https://developer.apple.com/videos/play/wwdc2021/10017
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Ҿ༻ 2
Async/Await and the Future of Combine
https://benscheirman.com/2021/06/async-await-and-the-future-of-combine/
URLsessionΛ༻͍ͨHTTPϦΫΤετͷํ๏(Swift, Xcode)
https://qiita.com/shungo_m/items/64564fd822a7558ac7b1
Core DataΛόοΫάϥϯυͰ͏
https://www.2nd-walker.com/2020/10/09/swift-using-coredata-in-background/
{JSON} Placeholder
https://jsonplaceholder.typicode.com/
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Thank you!