Offline-First Apps with PouchDB at Node.js Interactive

Web and mobile apps shouldn't stop working when there's no network connection. Based on Apache CouchDB, PouchDB is an open source syncing JavaScript database that runs within a web browser. Offline-first apps that use PouchDB can provide a better, faster user experience—both offline and online.

Learn how to build offline-enabled responsive mobile web apps using the HTML5 Offline Application Cache and PouchDB. We’ll also discuss how to build cross-platform apps or high-fidelity prototypes using PouchDB, Cordova, and Ionic. PouchDB can also be run within Node.js and on devices for Internet of Things (IoT) applications.

This talk includes code examples for creating a PouchDB database, creating a new document, updating a document, deleting a document, querying a database, synchronization PouchDB with a remote database, and live updates to a user interface based on database changes.

Transcript

1. @BradleyHolt! Offline-First Apps with PouchDB Node.js Interactive Wednesday, December 9, 2015 Bradley Holt, Developer Advocate
2. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
3. @BradleyHolt! Image Credits: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons; Joan Touzet (@wohali), ASF Member, CouchDB PMC Member
4. @BradleyHolt! Image Credit: Device landscape by Jeremy Keith, on Flickr Not just mobile first…!
5. @BradleyHolt! Image Credit: Cloud Formation Over the Adirondacks by Bradley Holt Offline First! Because being offline shouldn't be an error condition.!
6. @BradleyHolt! Doesn't ubiquitous connectivity make offline- enabled apps unnecessary?! Image Credit: Cell phone tower by Gary Lerude, on Flickr
7. @BradleyHolt! No.! Image Credit: Internet Splat Map by Steve Jurvetson, on Flickr
8. @BradleyHolt! Quite the opposite, in fact.! Image Credit: Tangled Network by Bruno Girin, on Flickr
9. @BradleyHolt! Ubiquitous connectivity is driving the demand for 
 offline capabilities.! Image Credit: Wired by Alexandre Duret-Lutz, on Flickr
10. @BradleyHolt! How?! Image Credit: connect me to BR549 by frankieleon, on Flickr
11. @BradleyHolt! The Eight Fallacies of Distributed Computing 1.  The network is reliable 2.  Latency is zero 3.  Bandwidth is infinite 4.  The network is secure 5.  Topology doesn't change 6.  There is one administrator 7.  Transport cost is zero 8.  The network is homogeneous Text Credit: The Eight Fallacies of Distributed Computing by Peter Deutsch | Image Credit: Pneumatic Central by Sleestak, on Flickr
12. @BradleyHolt! Image Credit: Connected version 2 by Hans Kylberg, on Flickr Offline-first is the only way 
 to achieve a true, 100% 
 always-on user experience.* ! *assuming the device is reliable!
13. @BradleyHolt! Faster User Experience! Image Credit: Speed DLR on Doklands by Umberto Rotundo, on Flickr
14. @BradleyHolt! Works Offline! Image Credit: Lynn Camp Prong (Explored) by AllieKF, on Flickr
15. @BradleyHolt! Battery and Bandwidth! Image Credit: Panorama of the Molasses Disaster site by Boston Public Library, on Flickr
16. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
17. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
18. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
19. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
20. @BradleyHolt! Image Credit: A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons
21. @BradleyHolt!
22. @BradleyHolt! Frontend Web Apps •  Build responsive mobile web apps that work offline •  PouchDB adapters available for many popular frameworks •  Enable full offline usage with service workers
23. @BradleyHolt! Backend Web Apps •  Use PouchDB as the database for your Node.js applications •  Installable via npm (pouchdb) •  Use PouchDB Server (pouchdb-server) as a drop-in replacement for CouchDB
24. @BradleyHolt! Mobile Apps •  Hybrid Mobile Web Apps •  HTML5, CSS and JavaScript apps compiled into native mobile apps •  Fully-featured, cross-platform native apps •  High-fidelity prototypes •  Native Mobile Web Apps •  Cloudnat Sync for iOS •  Cloudant Sync for Android
25. @BradleyHolt! Desktop Apps •  Use Electron to build cross-platform desktop apps with web technologies •  Formerly known as Atom Shell •  HTML5, CSS and JavaScript apps compiled into native desktop apps
26. @BradleyHolt! Internet of Things (IoT) Apps •  Headless Node.js apps •  PouchDB includes a LevelDB adapter for use in Node.js •  Redis, Riak, and in-memory adapters are also available •  Good for: •  Internet of Things (IoT) applications •  Content delivery networks (CDN) •  Purpose-built devices Image Credit: Ethernet IoT Starter Kit
27. @BradleyHolt! PouchDB Code Examples
28. @BradleyHolt!
29. @BradleyHolt! JSON Documents {
 _id: "6EF9D2B0-13D3-1378-8D30-39E3CE0B36C2",
 _rev: "1-0b457efcf82fb29492ef927ba5b6ee15",
 type: "Feature",
 geometry: {
 type: "Point",
 coordinates: [
 -71.1028,
 42.3691
 ]
 },
 properties: {
 session_id: "3486b13f-7b8a-8a96-dfbf-9b82800e367f",
 timestamp: 1422928591717
 }
 }
30. @BradleyHolt! Creating a Local PouchDB Database var db = new PouchDB("smart-meter");" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/01-create-local-database.js
31. @BradleyHolt! Creating a Remote PouchDB Database var remoteDb = new PouchDB("https://bradley-holt.cloudant.com/smart-meter");" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/02-create-remote-database.js
32. @BradleyHolt! Cross-Origin Resource Sharing (CORS) •  Enable Cross-Origin Resource Sharing (CORS) on remote database •  Browsers place security restrictions on cross-site HTTP requests •  If you run into a problem, remember this warning! Image Credit: Grunge Warning Sign - Do Not Read This Sign by Nicolas Raymond, on Flickr
33. @BradleyHolt! Creating a New Document var db = new PouchDB("smart-meter");" db.put({" _id: "2014-11-12T23:27:03.794Z"," kilowatt_hours: 14" }).then(function() {" console.log("Document created");" }).catch(function(error) {" console.log(error);" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/04-create-document-put.js
34. @BradleyHolt! Updating a Document db.put({" _id: "2014-11-12T23:27:03.794Z"," kilowatt_hours: 14" }).then(function(response) {" return db.get(response.id);" }).then(function(doc) {" // Update the value for kilowatt hours" doc.kilowatt_hours = 15;" // Put the document back to the database" return db.put(doc);" }).catch(function(error) {" console.log(error);" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/05-update-document.js
35. @BradleyHolt! Deleting a Document db.put({" _id: "2014-11-12T23:27:03.794Z"," kilowatt_hours: 14" }).then(function(response) {" // Get the document" return db.get(response.id);" }).then(function(doc) {" // Remove the document from the database" return db.remove(doc);" }).catch(function(error) {" console.log(error);" });" " https://github.com/bradley-holt/offline-first/blob/master/pouchdb/06-delete-document.js
36. @BradleyHolt! Querying a Database with allDocs! db.bulkDocs([" {_id: "2014-11-12T23:27:03.794Z", kilowatt_hours: 14}," {_id: "2014-11-13T00:52:01.471Z", kilowatt_hours: 15}," {_id: "2014-11-13T01:39:28.911Z", kilowatt_hours: 16}," {_id: "2014-11-13T02:52:01.471Z", kilowatt_hours: 17}" ]).then(function(result) {" // Get all documents" return db.allDocs({include_docs: true});" }).then(function(response) {" console.log(response);" }).catch(function(error) {" console.log(error);" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/07-query-database-all-docs.js
37. @BradleyHolt! allDocs Options •  include_docs" •  conflicts" •  attachments" •  startkey" •  endkey" •  inclusive_end (true by default) •  limit" •  skip" •  descending" •  key" •  keys"
38. @BradleyHolt! Querying a Database with Map/Reduce •  Most queries can be done with allDocs (in PouchDB) •  Map functions transform documents into indexes •  Reduce functions aggregate results of Map functions •  _sum" •  _count" •  _stats"
39. @BradleyHolt! Querying a Database with PouchDB Find •  Based on Cloudant Query (Mango) •  MongoDB-style query language •  Define fields to index Image Credit: Mango with section on a white background by bangdoll, on Flickr
40. @BradleyHolt! Listening for Database Changes var changes = remoteDb.changes({" since: "now"" }).on("change", function(change) {" // A document has changed" console.log(change);" }).on("complete", function(info) {" // changes() was canceled" console.log(info);" }).on("error", function(error) {" // changes() has errored" console.log(error);" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/11-database-changes.js
41. @BradleyHolt! Bidirectional, Live Replication var db = new PouchDB("smart-meter");" var remoteDb = new PouchDB(" "https://bradley-holt.cloudant.com/smart-meter"" );" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/10-replicate-database-live.js
42. @BradleyHolt! Bidirectional, Live Replication var sync = db.sync(remoteDb, {" live: true," retry: true" }).on("change", function(info) {" // Replication has written a new document" console.log(info);" }).on("complete", function(info) {" // Replication has complete or been cancelled" console.log(info);" }).on("error", function(error) {" // Replication has stopped due to an unrecoverable failure" console.log(error);" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/10-replicate-database-live.js
43. @BradleyHolt!
44. @BradleyHolt! Image Credits •  A mockup of the golden Apple iPhone 5S by Zach Vega, on Wikimedia Commons <https://commons.wikimedia.org/wiki/File:IPhone_5s.png> •  Joan Touzet (@wohali), ASF Member, CouchDB PMC Member <https://twitter.com/wohali/status/595689720933445632> •  Device landscape by Jeremy Keith, on Flickr <https://flic.kr/p/anLcHu> •  Cloud Formation Over the Adirondacks by Bradley Holt <https://twitter.com/BradleyHolt/status/623030107679002624> •  Cell phone tower by Gary Lerude, on Flickr <https://flic.kr/p/crLdJE> •  Internet Splat Map by Steve Jurvetson, on Flickr <https://flic.kr/p/5Gky> •  Tangled Network by Bruno Girin, on Flickr <https://flic.kr/p/7sdJw> •  Wired by Alexandre Duret-Lutz, on Flickr <https://flic.kr/p/2ZCmpx> •  connect me to BR549 by frankieleon, on Flickr <https://flic.kr/p/a1C62U> •  Pneumatic Central by Sleestak, on Flickr <https://flic.kr/p/mRvRQ> •  Connected version 2 by Hans Kylberg, on Flickr <https://flic.kr/p/4yN2FZ> •  Speed DLR on Doklands by Umberto Rotundo, on Flickr <https://flic.kr/p/7GmcUo> •  Lynn Camp Prong (Explored) by AllieKF, on Flickr <https://flic.kr/p/o6q1UG> •  Panorama of the Molasses Disaster site by Boston Public Library, on Flickr <https://flic.kr/p/8t8KCM> •  Ethernet IoT Starter Kit <https://developer.mbed.org/platforms/IBMEthernetKit/> •  Grunge Warning Sign - Do Not Read This Sign by Nicolas Raymond, on Flickr <https://flic.kr/p/cirSCd> •  Mango with section on a white background by bangdoll, on Flickr <https://flic.kr/p/9CBP2h>
45. @BradleyHolt! Bradley Holt Developer Advocate @BradleyHolt github.com/bradley-holt