Browsers behind your back at Berlin JS

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. INDEXEDDB
22. @philnash
23. OBJECT STORE @philnash
24. ASYNCHRONOUS @philnash
25. TRANSACTIONAL @philnash
26. LOW LEVEL @philnash
27. USE A LIBRARY • idb • localForage • Dexie • PouchDB @philnash
28. SERVICE WORKERS LOVE PROMISES @philnash
29. 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
30. 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
31. DEMO
32. BACKGROUND SYNC API
33. @philnash
34. @philnash
35. BACK ONLINE API
36. SUPPORT 49 beta devdevdevboo @philnash
37. ON THE PAGE navigator.serviceWorker.ready.then(function(reg) { reg.sync.register('back-online'); }); 01. 02. 03. @philnash
38. IN THE SERVICE WORKER self.addEventListener('sync', function(event) { if (event.tag === 'back-online') { // do something } }); 01. 02. 03. 04. 05. @philnash
39. DEMO
40. THE FUTURE
41. BACKGROUND FETCH API
42. 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
43. IN THE SERVICE WORKER self.addEventListener('backgroundfetched', function(event) { if (event.tag === 'downloads') { event.updateUI('largeFile.mp3 downloaded.'); } }); 01. 02. 03. 04. 05. @philnash
44. IN THE SERVICE WORKER Other events: • backgroundfetchfail • backgroundfetchabort • backgroundfetchclick @philnash
45. PERIODIC SYNC API
46. 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
47. 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
48. DEMO
49. BLOG POST http:/ /bit.ly/bg-sync @philnash
50. THANKS
51. 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
52. THANKS! @philnash http:/ /philna.sh http:/ /jsconf.philna.sh philnash@twilio.com