Progressive Web Apps und Project Fugu: Das nächste Level für Cross-Platform-Apps

Progressive Web Apps (PWA) ermöglichen es Ihnen, Businessanwendungen für den Browser zu entwickeln, die sich zugleich wie native Anwendungen anfühlen und dabei sogar offline-fähig sind. Dank Project Fugu stehen diese PWAs ihren nativen Gegenstücken in nichts nach! Erfahren Sie in diesem Workshop, wie Sie erfolgreich ihre eigenen PWAs entwickeln!

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1. Progressive Web Apps und Project Fugu Das nächste Level für Cross-Platform-Apps Christian Liebel Steffen Jahr @christianliebel @steffenjahr Consultant Consultant
2. Feel free to ask questions anytime! Your instructors Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu Steffen Jahr Christian Liebel
3. 09:00–10:30 Block 1 10:30–11:00 Break 11:00–12:30 Block 2 12:30–13:30 Break 13:30–15:00 Block 3 15:00–15:30 Break 15:30–17:00 Block 4 Timetable Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
4. Proposal 09:00–10:30 Block 1 10:30–10:45 Break 10:45–12:30 Block 2 12:30–13:30 Break 13:30–15:00 Block 3 15:00–15:15 Break 15:15–16:30 Block 4 Timetable Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
5. Things NOT to expect - Blueprint for PWA development - No AuthN/AuthZ - No 1:1 support Things To Expect - Extensive/up-to-date insights into PWA and Project Fugu - A productivity app use case that works on your desktop & smartphone - Lots of fun Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
6. https://paint.js.org – Productivity app – Draw images – Lots of actions & tools – Installable – Read/save files – Copy/paste images from/to clipboard – Share files to other apps – Register for file extensions Demo Use Case Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
7. (Workshop Edition) – Productivity app – Draw images – Lots of actions & tools – Installable – Read/save files – Copy/paste images from/to clipboard – Share files to other apps – Register for file extensions Demo Use Case Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
8. Setup complete? (Node.js, Google Chrome, Editor, Git) Setup (1/3) LAB Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
9. Optional Download and install Chrome Canary: https://www.google.com/intl/de/chrome/canary/ Setup (2/3) LAB Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
10. git clone https://github.com/thinktecture/basta- spring-2021-pwa-fugu.git cd basta-spring-2021-pwa-fugu npm i npm start Setup (3/3) LAB Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
11. Paint PWA Capabilitie s Progressive Enhanceme nt Agenda Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
12. Paint PWA Capabilities Progressive Enhancement Agenda Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
13. Canvas – Plain bitmap for the web – Cross-platform, hardware- accelerated graphics operations – Supports different contexts (2D, 3D: WebGL, WebGL 2.0) – Supported on all evergreen browsers and on IE 9+ Paint Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
14. Canvas Add a canvas element to app.component.html (line 5): <canvas #canvas width="600" height="480"></canvas> Query the canvas element in app.component.ts (line 10): @ViewChild('canvas') canvas: ElementRef<HTMLCanvasElement>; context: CanvasRenderingContext2D; Paint EX #1 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
15. Canvas 2D Context fillRect(x, y, width, height) strokeRect(x, y, width, height) beginPath() moveTo(x, y) lineTo(x, y) fill() stroke() Paint Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
16. Canvas 2D Context Get the 2D context and prepare the canvas in app.component.ts in the method ngAfterViewInit(): const canvas = this.canvas.nativeElement; const ctx = this.context = canvas.getContext('2d'); ctx.fillStyle = 'white'; ctx.fillRect(0, 0, canvas.width, canvas.height); ctx.fillStyle = 'black'; Paint EX #2 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
17. Low-latency Rendering Paint Web pages need to synchronize with the DOM on graphics updates causing latencies that can make drawing difficult Low-latency rendering skips syncing with the DOM with can lead to a more natural experience Supported on Chrome (Chrome OS and Windows only) Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
18. Low-latency Rendering Opt-in to low-latency rendering (app.component.ts): const ctx = this.context = canvas.getContext('2d', { desynchronized: true }); Paint EX #3 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
19. Pointer Events Paint Users nowadays use different input methods, cross-platform apps should cover all of them Pointer Events offer an abstract interface to catch all input methods (pointerdown, pointermove, pointerup) event.offsetX/event.offsetY contain the pointer’s position relative to the listener Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
20. Pointer Events Add event listeners (app.component.html and app.component.ts): <canvas #canvas width="600" height="480" (pointerdown)="onPointerDown($event)" (pointermove)="onPointerMove(canvas, $event)" (pointerup)="onPointerUp()"></canvas> onPointerMove(canvas: HTMLCanvasElement, event: PointerEvent): void { this.context.fillRect(~~event.offsetX, ~~event.offsetY, 2, 2); } Paint EX #4 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
21. Bresenham Line Algorithm The user may move faster than the input can be processed For this case, we need to remember the previous point and interpolate the points in between The Bresenham line algorithm calculates the missing pixels between two given points Paint Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
22. Bresenham Line Algorithm Update the method onPointerMove() in app.component.ts: if (this.previousPoint) { const currentPoint = {x: Math.floor(event.offsetX), y: Math.floor(event.offsetY)}; const points = this.paintService.bresenhamLine(this.previousPoint.x, this.previousPoint.y, currentPoint.x, currentPoint.y); for (const {x, y} of points) { this.context.fillRect(x, y, 2, 2); this.previousPoint = currentPoint; } } Paint EX #5 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
23. Color Selection For this demo, we will only implement the brush tool. However, we want to bring in some color. A simple method to implement a color selection is to use the HTML color-type input element that shows the native color picker: <input type="color"> Paint Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
24. Color Selection 1. In app.component.html, add the following input to the <nav> node: <input type="color" (change)="colorChange($event)"> 2. In app.component.ts, add the following code in the method colorChange(): this.context.fillStyle = $event.target.value; Paint EX #6 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
25. Paint PWA Capabilitie s Progressive Enhanceme nt Agenda Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
26. Responsive Linkable Discoverable Installable App-like Connectivity Independent Fresh Safe Re-engageable Progressive Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
27. Web App Manifest Service Worker Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
28. Web App Manifest Distinguishes Web Apps from Websites JSON-based file containing metadata for apps only Apps can be identified by search engines, app store providers, etc. PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
29. manifest.webmanifest { "short_name": "Paint", "name": "Paint Workshop", "theme_color": "white", "icons": [{ "src": "icon.png", "sizes": "512x512" }], "start_url": "/index.html", "display": "standalone", "shortcuts": [/* … */] } PWA Names Icons Display Mode Shortcuts Start URL Theme color (status bar/window bar) Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
30. Manifest Display Modes PWA browser minimal-ui standalone fullscreen Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
31. Manifest Icon Purposes (any) any context (e.g. app icon) monochrome different color requirements (at risk) maskable user agent masks icon as required PWA Safe Zone Windows iOS Android Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
32. Web App Manifest 1. In your console, run: npx ng add @angular/pwa 2. Update the new file manifest.webmanifest and set: a) name and short_name to values of your choice b) theme_color to #000080 and background_color to #808080 3. In index.html, set theme_color to #000080 as well. 4. Run npm run start 5. Test manifest in DevTools: F12 > Application > Manifest PWA EX #7 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
33. Manifest Shortcuts PWA Secondary entrypoints for your application (e.g., home screen quick actions, jump lists, …) Static definition in Web App Manifest Dynamic API may follow in the future Supported by Google Chrome for Android Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
34. Web App Manifest 1. In manifest.webmanifest, add (at least) the following shortcut: "shortcuts": [{ "name": "About Paint", "short_name": "About", "description": "Show information about Paint", "url": "/index.html", "icons": [{ "src": "assets/icons/icon-512x512.png", "sizes": "512x512" }] }], 2. Test in DevTools: F12 > Application > Manifest PWA EX #8 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
35. Web App Manifest – Chrome Installability Signals Web App is not already installed Meets a user engagement heuristic (previously: user has interacted with domain for at least 30 seconds) Includes a Web App Manifest that has short_name or name, at least a 192px and 512px icon, a start_url and a display mode of fullscreen, standalone or minimal-ui Served over HTTPS Has a registered service worker with a fetch event handler PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
36. Service Worker JavaScript snippet executed in an own thread, registered by the website Acts as a controller, proxy, or interceptor Has a cache to store responses (for offline availability and performance) Can wake up even when the website is closed and perform background tasks (e.g., push notifications or sync) PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
37. Service Worker PWA Service Worker Internet Website HTML/JS Cache fetch Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
38. NgServiceWorker Angular CLI supports Service Worker generation by simply adding PWA support: ng add @angular/pwa One-size-fits-all Service Worker Pre-defined functionality, limited customizability PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
39. Workbox Toolchain by Google Includes a CLI Generates a service worker implementation from directory contents (e.g., build output, or our development directory) Allows you to modify the service worker behavior (maximum flexibility) PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
40. Service Worker 1. Start build with npm run build -- --prod 2. Go to dist folder: cd dist/basta-spring-2021-pwa-fugu 3. Start with npx lite-server 4. Test in DevTools: F12 > Application > Service Worker 5. Install the app: Address Bar > ⊕ Install PWA EX #9 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
41. Push Notifications Just as native apps, PWAs can receive push notifications Combination of two technologies: Web Notifications and Push API (Not supported on Safari for macOS, iOS and iPadOS!) Progressive Web Apps und Project Fugu Das nächste Level für Cross-Platform-Apps PWA
42. Service Worker Debugging More information on installed service workers can be found on • chrome://serviceworker- internals (Google Chrome) • about:serviceworkers (Mozilla Firefox) PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
43. Service Worker Debugging PWA Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
44. Lighthouse PWA Auditing tool by Google, integrated in Chrome DevTools Automatically checks performance metrics, PWA support, accessibility, SEO and other best practices and gives tips on how to improve Can simulate mobile devices Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
45. Lighthouse 1. Make sure only one tab/window of your PWA is open 2. Open DevTools: F12 > Lighthouse 3. Make sure to select at least the “Progressive Web App” category 4. Click “Generate report” PWA EX #10 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
46. Paint PWA Capabilities Progressive Enhancement Agenda Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
47. Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
48. Project Fugu Capabilities »Let’s bring the web back – API by API« Thomas Steiner, Google Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
49. Capabilities Contacts Picker Screen Wake Lock API File System Access API Shape Detection API Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
50. Capabilities https://goo.gle/fugu-api-tracker Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
51. Fugu Process – Write an Explainer (https://github.com/WICG/native-file- system/blob/master/EXPLAINER.md) – Discuss capability with developers, browser vendors, standard orgs – Iterate – Compile a design document – W3C TAG Review (https://github.com/w3ctag/design- reviews/issues/390) – Formal spec within Web Incubator Community Group (WICG, https://wicg.github.io/native-file-system/) Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
52. Fugu Process – Implementation in Chromium – Launches behind a flag (chrome://flags/#enable-experimental-web- platform-features) – Origin Trial (https://developers.chrome.com/origintrials/) – Transfer to W3C Working Group + Recommendation? Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
53. Capabilities navigator.share({ url: 'http://example.com' }); ShareIntent DataTransferManager … NSSharingServicePicker Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
54. File System Access API Some applications heavily rely on working with files (e.g. Visual Studio Code, Adobe Photoshop, …) File System Access API allows you to open, save and override files and directories Shipped with Google Chrome 86 Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
55. File System Access API 1. Add the following buttons to the <nav> bar in app.component.html (before the color input): <button (click)="open()">Open</button> <button (click)="save()">Save</button> <button (click)="copy()">Copy</button> <button (click)="paste()">Paste</button> <button (click)="share()">Share</button> Capabilities EX #11 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
56. File System Access API 2. Add the following lines at the top of app.component.ts: private fileOptions = { types: [{ description: 'PNG files', accept: {'image/png': ['.png']} }] }; Capabilities EX #11 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
57. File System Access API 4. Add the following lines in the method save of app.component.ts: const blob = await this.paintService.toBlob(this.canvas.nativeElement); const handle = await (window as any).showSaveFilePicker(this.fileOptions); const writable = await handle.createWritable(); await writable.write(blob); await writable.close(); Capabilities EX #11 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
58. File System Access API Add the following code int the method open() of app.component.ts: const [handle] = await (window as any).showOpenFilePicker(this.fileOptions); const file = await handle.getFile(); const image = await this.paintService.getImage(file); this.context.drawImage(image, 0, 0); Capabilities EX #12 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
59. Async Clipboard API Allows reading from/writing to the clipboard in an asynchronous manner (UI won’t freeze during long-running operations) Reading from the clipboard requires user consent first (privacy!) Supported by Chrome, Edge and Safari Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
60. Async Clipboard API Add the following code in the method copy() of app.component.ts: const blob = await this.paintService.toBlob(this.canvas.nativeElement); await navigator.clipboard.write([ new ClipboardItem({[blob.type]: blob}) ]); Capabilities EX #13 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
61. Async Clipboard API Add the following code in the method paste() of app.component.ts: const clipboardItems = await navigator.clipboard.read(); for (const clipboardItem of clipboardItems) { for (const type of clipboardItem.types) { if (type === 'image/png') { const blob = await clipboardItem.getType(type); const image = await this.paintService.getImage(blob); this.context.drawImage(image, 0, 0); } } } Capabilities EX #14 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
62. Web Share API Allows sharing a title, URL, text, or files API can only be invoked as a result of a user action (i.e. a click or keypress) Files supported in Chrome on Android, Edge on Windows Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
63. Web Share API Add the following code in the paste() method in the app.component.ts: const blob = await this.paintService.toBlob(this.canvas.nativeElement); const file = new File([blob], 'untitled.png', {type: 'image/png'}); const item = {files: [file], title: 'untitled.png'}; if (await navigator.canShare(item)) { await navigator.share(item); } Capabilities EX #15 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
64. File System Handling API Register your PWA as a handler for file extensions Requires installing the application first Declare supported extensions in Web App Manifest and add imperative code to your application logic Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
65. File System Handling API 1. Enable the following flag in Chrome Canary and restart the browser: chrome://flags/#file-handling-api 2. Add the following property to your manifest (manifest.webmanifest): "file_handlers": [{ "action": "/index.html", "accept": { "image/png": [".png"] } }] Capabilities EX #16 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
66. File System Handling API 3. Add the following code to the bottom of the ngAfterViewInit() method of app.component.ts: if ('launchQueue' in window) { (window as any).launchQueue.setConsumer(async params => { const [handle] = params.files; if (handle) { const file = await handle.getFile(); const image = await this.paintService.getImage(file); ctx.drawImage(image, 0, 0); } }); } 4. Re-generate Service Worker: npm run workbox generateSW Capabilities EX #16 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
67. Summary - Project Fugu helps the web to become more and more capable - Project Fugu APIs could bring many more app experiences to the web (IDEs, productivity apps, etc.) - But: Web is threatened by alternative approaches and platforms, support for modern Web API varies from platform to platform - You can make a difference! - File bugs in browser engine bugtrackers - File Fugu requests: https://goo.gle/new-fugu-request Capabilities Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
68. Paint PWA Capabilitie s Progressive Enhanceme nt Agenda Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
69. Overview Use available interfaces and functions of a system (opposite of Graceful Degradation) Users with modern, feature-rich browsers get a better experience Apps are available on older browsers, but with limited functionality Concept: Browser feature support should grow over time—thereby more users can enjoy an increasing number of features Progressive Enhancement Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
70. Overview if ('serviceWorker' in navigator) { navigator.serviceWorker.register(…) .then(() => /* … */); } In JavaScript: check whether an API/feature is available. If yes—use it! Otherwise: 1. Disable the functionality 2. Fall back to an alternative API (if available) Progressive Enhancement Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
71. Disabling unsupported features In app.component.ts, disable the buttons in case the respective API does not exist, e.g.: isClipboardDisabled = !('clipboard' in navigator && 'read' in navigator.clipboard); And update the buttons in the app.component.html with a [disabled] attribute, e.g.: <button (click)="copy()" [disabled]="isClipboardDisabled">Copy</button> Progressive Enhancement EX #17 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
72. Disabling unsupported features 1. Open: window.showOpenFilePicker() 2. Save: window.showSaveFilePicker() 3. Copy: navigator.clipboard + navigator.clipboard.read() 4. Paste: navigator.clipboard + navigator.clipboard.write() 5. Share: navigator.canShare() Progressive Enhancement EX #17 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
73. Providing an alternative implementation 1. In app.component.ts in the method save(), test for the existence of the showSaveFilePicker() method on the navigator object. 2. If the method does not exist, fall back to the following code for save: const anchor = this.document.createElement('a'); const url = URL.createObjectURL(blob); anchor.href = url; anchor.download = ''; anchor.click(); URL.revokeObjectURL(url); Progressive Enhancement EX #18 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
74. Deployment Electron/Capacitor JS HTML CSS .ipa .exe .app ELF .apk .appx Single-Page Application Capacitor Electron Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
75. (Simplified) Store Deployments https://example.com .appx .apk Server Microsoft Store Play Store Source Files Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
76. Run app on your device https://ngrok.com/download ngrok http 3000 EX #19 Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
77. Crunch Time LAB Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
78. Q&A Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
79. New powerful APIs regularly ship with new releases of Chromium-based browsers Some only add minor finishing touches, others enable whole application categories as productivity apps to finally make the shift to the web Some APIs already made their way into other browsers (e.g., Web Share) Fugu process makes sure that capabilities are implemented in a secure, privacy-preserving manner Let’s make the web a more capable platform! Summary Das nächste Level für Cross-Platform-Apps Progressive Web Apps und Project Fugu
80. Thank you for your kind attention! Christian Liebel Steffen Jahr @christianliebel @steffenjahr christian.liebel@thinktecture.com steffen.jahr@thinktecture.com