Offline Sync for Progressive Web Apps at Vermont Code Camp

With the introduction of Progressive Web Apps and web platform APIs such as persistent storage, payments, geolocation, and push notifications, the web platform is taking on native apps. One important aspect of Progressive Web Apps is the concept of building your app to be Offline First. With an Offline First approach, you design your app for the most resource-constrained environment first. This approach provides a consistent user experience whether the user's device has no connectivity, limited connectivity, or great connectivity. One of the biggest benefits of Offline First apps is that they can be very fast, as they provide zero-latency access to content and data stored directly on the device.

The Service Worker API can do most of the heavy lifting when it comes to storing content and assets for Offline First Progressive Web Apps. A bigger challenge can be storing and sync'ing your app's data. One of the best answers today for offline sync for Progressive Web Apps is a combination of Apache CouchDB (an open source document database), Hoodie (an open source Node.js backend for Offline First apps), and PouchDB (an open source JavaScript database that syncs). This stack can provide you with the starting point for your own Progressive Web App mobile backend and frontend, and it's entirely open source!

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1. Vermont Code Camp Bradley Holt, Developer Advocate Saturday, September 16, 2017 Offline Sync for Progressive Web Apps
3. https://mobilefirstplatform.ibmcloud.com/blog/2016/01/13/ionic-hybrid-mobile-app-using-mobilefirst-platform-7-1-cli/ Native Mobile Apps
4. organic growth by Steve Jurvetson, on Flickr (CC BY 2.0). The Web Platform
5. W3C HTML5 Logo (CC BY 3.0).
6. Mobile First & the Mobile Web Screen size visualisation by Orde Saunders, on Flickr (CC BY 2.0).
7. https://responsivedesign.is/examples/css-conf-europe/
8. Evergreen by Basheer Tome, on Flickr (CC BY 2.0). Evergreen Browsers
9. mettalic weave by Joel Ormsby, on Flickr (CC BY 2.0). Polyfills
10. By Diseño Web Valencia, via Wikimedia Commons (CC BY-SA 4.0).
12. https://doesmysiteneedhttps.com/
13. Percentage of Web Pages Loaded by Firefox Using HTTPS https://letsencrypt.org/stats/
14. Web or Mobile App? iPhone 4 - Bottom View with Bumper by William Hook, on Flickr (CC BY-SA 2.0).
15. http://gph.is/2dhW35c
16. Progressive Web Apps (or how to have your cake and eat it too) German Chocolate Cake by Kimberly Vardeman, on Flickr (CC BY 2.0).
17. Progressive Web Apps A Progressive Web App provides both the discoverability of a web app and the reliable, fast, and engaging user experience of a native mobile app https://www.pokedex.org/
18. "I don’t want the web to equal native; I want the web to surpass it. I, for one, would prefer a reality where my home screen isn’t filled with the icons of startups and companies that have fulfilled the criteria of the gatekeepers. But a home screen filled with the faces of people who didn’t have to ask anyone’s permission to publish? That’s what I want!" –Jeremy Keith Adactio: Journal—Progressing the web | Jeremy Keith by Matthew Oliphant, on Flickr (CC BY-ND 2.0).
19. https://www.pwastats.com/
20. https://developers.google.com/web/showcase/2017/twitter
21. Geolocation API Network Information API IndexedDB WebRTC API Push API Notifications API Device Orientation API Screen Orientation API Permissions API Proximity API Pointer Lock API Vibration API Payment Request API Battery Status API Ambient Light Sensor API Service Worker API IBM Design Icons by International Business Machines Corporation (CC BY 4.0).
22. Offline First Progressive Web Apps must be Offline First in order to provide a reliable, fast, and engaging user experience regardless of network connectivity No Signal by Steve Hodgson, on Flickr (CC BY-SA 2.0).
23. speed 3 by Monkieyes, on Flickr (CC BY 2.0). Zero Latency Access to Content & Data
24. Offline, Online & ¯\_(ツ)_/¯
25. The Next Billion Internet Users the galaxy by tommy@chau, on Flickr (CC BY 2.0).
26. Cache content & assets with Service Workers Service Workers fetch diagram by Mozilla Contributors (CC-BY-SA 2.5).
27. Technological devices design created by D3images - Freepik.com | Texture 94 by Ellen van Deelen, on Flickr (CC BY 2.0). Sync is Hard
28. IBM Cloudant Apache CouchDB PouchDB
29. "CouchDB’s superpower is sync. Sometimes I even try to explain it to people by saying, 'CouchDB isn’t a database; it’s a sync engine.' It’s a way of efficiently transferring data from one place to another, while intelligently managing conflicts and revisions. It’s very similar to Git. When I make that analogy, the light bulb often goes off." –Nolan Lawson PouchDB & CouchDB: An interview with Nolan Lawson – CouchDB Blog
30. Apache CouchDB An open source document database featuring an HTTP API, JSON documents, clustering capabilities for horizontal scalability, and peer-to-peer replication http://couchdb.apache.org/
31. PouchDB An open source JavaScript database that syncs with anything that implements the CouchDB Replication Protocol https://pouchdb.com/
32. IBM Cloudant A fully-managed database-as-a-service (DBaaS) based on Apache CouchDB with additional full text and geospatial search capabilities https://cloudant.com/
33. Apache CouchDB Devices by Darwin Laganzon, on Pixabay (CC0 Public Domain). | Cloud by Raphael Silva, on Pixabay (CC0 Public Domain). PouchDB Browser-to- Cloud Sync
34. userdb-d76846 userdb-905cec userdb-adc95b userdb-c082f2 userdb-730bba userdb-c3d3e5 userdb-a1ec1f userdb-85a327 userdb-9b9aba userdb-85bcfe userdb-da3d25 One Database Per User database by Tim Morgan, on Flickr (CC BY 2.0). userdb-43ecb5 userdb-8a5dfa
36. Apache CouchDB Devices by Darwin Laganzon, on Pixabay (CC0 Public Domain). | Cloud by Raphael Silva, on Pixabay (CC0 Public Domain). PouchDB
37. Progressive Web Apps, Progressively Ensure your website is mobile friendly Improve an existing website Create a native app-like experience Leverage the web platform
38. Progressive Web Apps, Progressively •  Implement responsive web design •  Ensure cross-browser compatibility •  Test and improve web performance Ensure your website is mobile friendly Improve an existing website Create a native app-like experience Leverage the web platform
39. Progressive Web Apps, Progressively Ensure your website is mobile friendly •  Use an SSL/TLS certificate (Let's Encrypt is your friend) •  Add a Web App Manifest (name, author, icon, description, etc.) •  Use a Service Worker to make your app cache-first Improve an existing website Create a native app-like experience Leverage the web platform
40. Progressive Web Apps, Progressively Ensure your website is mobile friendly Improve an existing website •  Provide instant page transitions with a single-page (client-rendered) app •  Minimize time-to-interactive with the PRPL pattern •  Use a local database (IndexedDB, localForage, or PouchDB) Create a native app-like experience Leverage the web platform
41. Progressive Web Apps, Progressively Ensure your website is mobile friendly Improve an existing website Create a native app-like experience •  Ensure that each page can be addressed via a URL •  Implement server-side rendering for users without JavaScript •  Build a hybrid mobile app with a tool like Ionic or Apache Cordova Leverage the web platform
42. Shopping List Offline First Demo Apps (work in progress) A series of demo Progressive Web Apps, hybrid mobile apps, native mobile apps, and a desktop app—each built using a different stack.
43. https://github.com/ibm-watson-data-lab/shopping-list
44. Offline Camp From the Catskill Mountains, to the Central Coast of California, to Berlin, we're building the Offline First community, one campfire at a time Image credit: Aaron Ross
46. Get Involved in the Offline First Community! §  Join the Offline First Slack team: offlinefirst.org/chat/ §  Follow @OfflineCamp on Twitter §  Read the Offline Camp Medium publication: medium.com/offline-camp §  Join us at an upcoming Offline Camp: http://offlinefirst.org/camp/
47. Further Reading and Resources §  Offline Sync for Progressive Web Apps – IBM Watson Data Lab §  Voice of InterConnect – IBM Watson Data Lab §  Deploying the Hoodie Tracker demo app to IBM Bluemix §  Hoodie documentation on storing data with IBM Cloudant §  Offline Camp Medium publication §  Offline First resources §  Offline First on YouTube §  Make&Model (consultancy specializing in user experience design for Offline First apps) §  Neighbourhoodie Software (IBM Business Partner specializing in architecting Offline First apps)
48. Questions?