Browsers behind your back at 4Developers 2017

You’ve probably heard of the magic of a Service Worker when a user is offline, but what can we do for them when they get back online? We can take advantage of the Service Worker’s life outside of the page and start to perform actions in the background.

In this talk we’ll investigate the Background Sync API and the APIs that it depends upon, we’ll look at what you might use it for and see it in action. Once that is behind us we can take a peek into the future and even more background tasks with a look at the Periodic Sync API.

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Links:

Build the demo from the talk: https://www.twilio.com/blog/2017/02/send-messages-when-youre-back-online-with-service-workers-and-background-sync.html
The app from the demo: https://github.com/philnash/sms-messages-app/tree/background-sync
Background Sync explainer: https://github.com/WICG/BackgroundSync/blob/master/explainer.md

Background Fetch API: https://github.com/WICG/background-fetch

Transcript

1. BROWSERS BEHIND YOUR BACK
2. PHIL NASH @philnash http:/ /philna.sh philnash@twilio.com
3. BROWSERS BEHIND YOUR BACK
4. EMAIL IS PRETTY COOL @philnash
6. ON THE WEB? @philnash
7. PROGRESSIVE WEB APPS
8. @philnash
9. SENDING MESSAGES @philnash
10. LIKE OR FAVOURITE @philnash
11. ADD SHOPPING TO CART @philnash
12. LEAVING A COMMENT @philnash
13. @philnash
14. BACKGROUND SYNC API
15. BACKGROUND SYNC API • Service Worker • IndexedDB • Sync Event @philnash
16. DEMO
17. SERVICE WORKER
18. @philnash
19. @philnash
20. @philnash
21. DEMO
22. INDEXEDDB
23. @philnash
24. OBJECT STORE @philnash
25. ASYNCHRONOUS @philnash
26. TRANSACTIONAL @philnash
27. LOW LEVEL @philnash
28. USE A LIBRARY • idb • localForage • Dexie • PouchDB @philnash
29. SERVICE WORKERS LOVE PROMISES @philnash
30. CALLBACKS var request = indexedDB.open('messages', 1) request.onupgradeneeded = function(event) { var upgradeDb = event.result.target; upgradeDb.createObjectStore('outbox', { autoIncrement : true, keyPath: 'id' }); } request.onsuccess = function(event) { window.db = event.result.target; } 01. 02. 03. 04. 05. 06. 07. 08. 09. 10. @philnash
31. PROMISES idb.open('messages', 1, function(upgradeDb) { upgradeDb.createObjectStore('outbox', { autoIncrement : true, keyPath: 'id' }); }).then(function(db) { return window.db = db; }) 01. 02. 03. 04. 05. 06. 07. @philnash
32. DEMO
33. BACKGROUND SYNC API
34. @philnash
35. @philnash
36. BACK ONLINE API
37. SUPPORT 49 beta devdevdevboo @philnash
38. ON THE PAGE navigator.serviceWorker.ready.then(function(reg) { reg.sync.register('back-online'); }); 01. 02. 03. @philnash
39. IN THE SERVICE WORKER self.addEventListener('sync', function(event) { if (event.tag === 'back-online') { // do something } }); 01. 02. 03. 04. 05. @philnash
40. DEMO
41. THE FUTURE
42. BACKGROUND FETCH API
43. ON THE PAGE navigator.serviceWorker.ready.then(function(reg) { const url = "https://example.com/largeFile.mp3"; reg.backgroundFetch.fetch('downloads', [url], { icons: [], title: 'Downloading largeFile.mp3', totalDownloadSize: 1048576 }); }); 01. 02. 03. 04. 05. 06. 07. 08. @philnash
44. IN THE SERVICE WORKER self.addEventListener('backgroundfetched', function(event) { if (event.tag === 'downloads') { event.updateUI('largeFile.mp3 downloaded.'); } }); 01. 02. 03. 04. 05. @philnash
45. IN THE SERVICE WORKER Other events: • backgroundfetchfail • backgroundfetchabort • backgroundfetchclick @philnash
46. PERIODIC SYNC API
47. ON THE PAGE navigator.serviceWorker.ready.then(function(reg) { reg.periodicSync.register({ tag: 'get-latest-news', // default: '' minPeriod: 12 * 60 * 60 * 1000, // default: 0 powerState: 'avoid-draining', // default: 'auto' networkState: 'avoid-cellular' // default: 'online' }); }); 01. 02. 03. 04. 05. 06. 07. 08. @philnash
48. IN THE SERVICE WORKER self.addEventListener('periodicsync', function(event) { if (event.tag === 'get-latest-news') { // get the latest news! } }); 01. 02. 03. 04. 05. @philnash
49. DEMO
50. BLOG POST http:/ /bit.ly/bg-sync @philnash
51. THANKS
52. ICON CREDITS • Browser by Kimmi Studio from the Noun Project • Cloud by Kimmi Studio from the Noun Project • Gears by TS Graphics from the Noun Project • Database by Yo! Baba from the Noun Project • wifi by i cons from the Noun Project @philnash
53. THANKS! @philnash http:/ /philna.sh philnash@twilio.com