Offline-First Apps with PouchDB at That Conference

Mobile web 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 built using PouchDB can provide a better, faster user experience—both offline and online.

Learn how to use the HTML5 Offline Application Cache, PouchDB and Cloudant/CouchDB to build offline-enabled responsive mobile web apps. We’ll also discuss how to use PouchDB with Cordova/PhoneGap, Ionic, and Cloudant/CouchDB to build fully-featured, cross-platform native/hybrid apps or high-fidelity prototypes.

PouchDB runs in all modern mobile browser, in desktop browsers, within Cordova/PhoneGap and on the server side with Node.js. This talk will demonstrate 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 That Conference Wednesday, August 12, 2015 Bradley Holt, Developer Advocate
2. @BradleyHolt! Image Credit: Joan Touzet (@wohali), ASF Member, CouchDB PMC Member
3. @BradleyHolt! Image Credit: Device landscape by Jeremy Keith, on Flickr Not just mobile first…!
4. @BradleyHolt! Image Credit: Cloud Formation Over the Adirondacks by Bradley Holt Offline First! Because being offline shouldn't be an error condition.!
5. @BradleyHolt! Doesn't ubiquitous connectivity make offline- enabled apps unnecessary?! Image Credit: Cell phone tower by Gary Lerude, on Flickr
6. @BradleyHolt! No.! Image Credit: Internet Splat Map by Steve Jurvetson, on Flickr
7. @BradleyHolt! Quite the opposite, in fact.! Image Credit: Tangled Network by Bruno Girin, on Flickr
8. @BradleyHolt! Ubiquitous connectivity is driving the demand for 
 offline capabilities.! Image Credit: Wired by Alexandre Duret-Lutz, on Flickr
9. @BradleyHolt! How?! Image Credit: connect me to BR549 by frankieleon, on Flickr
10. @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
11. @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!
12. @BradleyHolt! Faster User Experience! Image Credit: Speed DLR on Doklands by Umberto Rotundo, on Flickr
13. @BradleyHolt! Works Offline! Image Credit: Lynn Camp Prong (Explored) by AllieKF, on Flickr
14. @BradleyHolt! Battery and Bandwidth! Image Credit: Panorama of the Molasses Disaster site by Boston Public Library, on Flickr
15. @BradleyHolt! Offline Patterns & Anti-Patterns •  Don't return an error for no reason •  Do let users view cached/saved data •  Do synchronize data when connected
16. @BradleyHolt! Offline Patterns & Anti-Patterns •  Don't return an error for no reason •  Do let users view cached/saved data •  Do synchronize data when connected
17. @BradleyHolt! Offline Patterns & Anti-Patterns •  Don't return an error for no reason •  Do let users view cached/saved data •  Do synchronize data when connected
18. @BradleyHolt! Offline Patterns & Anti-Patterns •  Don't return an error for no reason •  Do let users view cached/saved data •  Do synchronize data when connected
19. @BradleyHolt! Introducing PouchDB
20. @BradleyHolt! PouchDB •  A database in your web browser •  Can synchronize with any database that implements the CouchDB Replication Protocol •  Makes create, read, update and delete operations extremely fast
21. @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
 }
 }
22. @BradleyHolt! PouchDB Framework Adapters
23. @BradleyHolt! Responsive Mobile Web Apps, Hybrid Mobile Web Apps, or Internet of Things (IoT)
24. @BradleyHolt! Responsive Mobile Web Apps •  HTML5, CSS and JavaScript mobile web apps •  Responsive design •  Enhanced to enable offline usage
25. @BradleyHolt! Hybrid Mobile Web Apps •  Native mobile web apps built with HTML5, CSS and JavaScript •  Good for: •  Fully-featured, cross-platform native apps •  High-fidelity prototypes
26. @BradleyHolt! Internet of Things (IoT) •  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! Apache CouchDB
28. @BradleyHolt! Apache CouchDB •  JSON document database •  HTTP API •  Master-master replication
29. @BradleyHolt! IBM Cloudant •  Globally distributed data layer for web and mobile applications •  MongoDB-style queries •  Advanced geospatial capabilities •  Full text search indexing
30. @BradleyHolt! PouchDB and Cloudant Replication
31. @BradleyHolt! CouchDB Replication Protocol •  One-off, one way operation •  Peer-to-peer (masterless) •  Incremental •  Conflict detection
32. @BradleyHolt! Apache Cordova, PhoneGap and Ionic
33. @BradleyHolt! Apache Cordova and PhoneGap Image Credit: build.phonegap by Andrés Álvarez Iglesias, on Flickr
34. @BradleyHolt! Ionic •  Mobile-optimized HTML, CSS and JavaScript components •  Builds on Apache Cordova •  Utilizes AngularJS •  CLI installable via npm
35. @BradleyHolt! Using Cordova and Ionic $ npm install -g cordova ionic" $ ionic start energy-monitor tabs" $ cd energy-monitor" $ ionic platform add ios" $ ionic build ios" $ ionic emulate ios" Image Credit: Getting Started with Ionic
36. @BradleyHolt! HTML5 Offline Application Cache
37. @BradleyHolt! HTML5 Offline Application Cache •  Enables fully-functional offline web apps •  Stores files and assets for offline browsing •  Makes page loads very fast, even when online
38. @BradleyHolt! Cache Manifest File <html manifest="example.appcache">
 …
 </html>
 CACHE MANIFEST
 # v1 - 2015-01-08
 index.html
 logo.png
 app.css
 app.js
39. @BradleyHolt! PouchDB Code Examples
40. @BradleyHolt! Installing PouchDB <script src=
 "https://cdn.jsdelivr.net/pouchdb/3.5.0/pouchdb.min.js"
 ></script>
 CACHE MANIFEST
 # v2 - 2015-01-08
 index.html
 logo.png
 app.css
 app.js
 https://cdn.jsdelivr.net/pouchdb/3.5.0/pouchdb.min.js
41. @BradleyHolt! PouchDB Code Examples •  Creating a local PouchDB database •  Creating a remote PouchDB database •  Creating a new document •  Updating a document •  Querying a database •  Replicating PouchDB
42. @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
43. @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
44. @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
45. @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
46. @BradleyHolt! Updating a Document db.put({" _id: "2014-11-12T23:27:03.794Z"," kilowatt_hours: 14" }).then(function() {" return db.get("2014-11-12T23:27:03.794Z");" }).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
47. @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
48. @BradleyHolt! allDocs Options •  include_docs" •  conflicts" •  attachments" •  startkey" •  endkey" •  inclusive_end (true by default) •  limit" •  skip" •  descending" •  key" •  keys"
49. @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"
50. @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
51. @BradleyHolt! Bidirectionally Replicating a PouchDB Database 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/08-replicate-database.js
52. @BradleyHolt! Bidirectionally Replicating a PouchDB Database Promise.all([" db.bulkDocs([" {_id: "2014-11-12T23:27:03.794Z", kilowatt_hours: 14}," {_id: "2014-11-13T00:52:01.471Z", kilowatt_hours: 15}" ])," remoteDb.bulkDocs([" {_id: "2014-11-11T22:35:01.433Z", kilowatt_hours: 11}," {_id: "2014-11-12T00:43:01.633Z", kilowatt_hours: 13}" ])" ]).then(function() {" …" });" https://github.com/bradley-holt/offline-first/blob/master/pouchdb/09-replicate-database-bidirectional.js
53. @BradleyHolt! Bidirectionally Replicating a PouchDB Database db.sync(remoteDb, {" live: false," retry: false" }).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/09-replicate-database-bidirectional.js
54. @BradleyHolt! Location Tracker •  Stores data locally in PouchDB •  Front end built with AngularJS •  Authentication logic built with Node.js •  User interface built with Leaflet •  Replicates location data to Cloudant •  More info: https://cloudant.com/location-tracker/
55. @BradleyHolt! A Deep Dive into Offline-First with PouchDB and IBM Cloudant Date: Thursday, August 27, 2015 Time: 1:00 PM - 2:00 PM EDT Register at: https://cloudant.com/resources/webinars/
56. @BradleyHolt! Image Credits •  Joan Touzet (@wohali), ASF Member, CouchDB PMC Member <https://twitter.com/wohali/status/595689720933445632> •  Device landscape by Jeremy Keith, on Flickr <https://www.flickr.com/photos/adactio/6153481666> •  Cloud Formation Over the Adirondacks by Bradley Holt <https://twitter.com/BradleyHolt/status/623030107679002624> •  Cell phone tower by Gary Lerude, on Flickr <https://www.flickr.com/photos/garylerude/7511464618/> •  Internet Splat Map by Steve Jurvetson, on Flickr <https://www.flickr.com/photos/jurvetson/916142/> •  Tangled Network by Bruno Girin, on Flickr <https://www.flickr.com/photos/brunogirin/73014722/> •  Wired by Alexandre Duret-Lutz, on Flickr <https://www.flickr.com/photos/gadl/1308489717/> •  connect me to BR549 by frankieleon, on Flickr <https://www.flickr.com/photos/armydre2008/5914251874/> •  Pneumatic Central by Sleestak, on Flickr <https://www.flickr.com/photos/dlanod/235990854> •  Connected version 2 by Hans Kylberg, on Flickr <https://www.flickr.com/photos/visulogik/2340179011/> •  Speed DLR on Doklands by Umberto Rotundo, on Flickr <https://www.flickr.com/photos/turyddu/4394742730/> •  Lynn Camp Prong (Explored) by AllieKF, on Flickr <https://www.flickr.com/photos/allie_k/14501117120> •  Panorama of the Molasses Disaster site by Boston Public Library, on Flickr <https://www.flickr.com/photos/boston_public_library/4901555337/> •  Ethernet IoT Starter Kit <https://developer.mbed.org/platforms/IBMEthernetKit/> •  build.phonegap by Andrés Álvarez Iglesias, on Flickr <https://www.flickr.com/photos/doctorserone/5682929553> •  Getting Started with Ionic <http://ionicframework.com/getting-started/> •  Grunge Warning Sign - Do Not Read This Sign by Nicolas Raymond, on Flickr <https://www.flickr.com/photos/80497449@N04/7417352980> •  Mango with section on a white background by bangdoll, on Flickr <https://www.flickr.com/photos/bangdoll/5665235102>
57. @BradleyHolt! Bradley Holt Developer Advocate bradley.holt@us.ibm.com @BradleyHolt github.com/bradley-holt