Realtime Apps with RethinkDB and Node.JS

Taking a look at building Realtime Apps with RethinkDB and Node.js

Transcript

1. Realtime Apps ...with RethinkDB and Node.JS MattCollins84
2. Realtime Apps ...with RethinkDB and Node.JS MattCollins84
3. What do we mean by “Realtime App”?
4. Pushing data to the user is what makes your app “realtime”.
6. Interactive Alive Engaging
7. Great User Experience
8. :(
9. Tracking state in realtime apps is hard
10. The database holds the state of your app Databases are slow Polling doesn’t scale
11. DB Message Queue App Server
12. DB Message Queue App Server
13. DB Web Queue Web App Server Mobile App Server Mobile Queue
14. DB Web Queue Web App Server Mobile App Server Mobile Queue Web App Server Web Queue
15. Open Source NoSQL DB JSON document store Distributed Really nice admin UI Designed for building realtime apps! Own query language - ReQL
16. RethinkDB Application cursor.next() cursor.each( (err, item) => { … } ) cursor.toArray( (err, results) => { … } )
17. r.db("nottsjs") .table("questions") [ { id: "cad7-470d-b8d0-e89900bcda0d", question: "What is your favourite colour?" score: 10 }, { id: "d5c9-d104-0d31-1c2f199b", question: "Where were you born?" score: 5 } ]
18. r.db("nottsjs") .table("questions") .filter( r.row("score").gt(5) ) [ { id: "cad7-470d-b8d0-e89900bcda0d", question: "What is your favourite colour?" score: 10 } ]
19. r.db("nottsjs") .table("questions") .changes() { new_val: { "id": "2cc9-497a-ae25-69c6710a9181" , "question": "How old are you?" , "score": 0 }, old_val: null }
20. RethinkDB Cluster Web App Server Web App Server Mobile App Server
21. RethinkDB Demo
22. JavaScript runtime Built on Googles V8 engine Non blocking I/O Event Driven Single threaded
23. I/O I/O
24. I/O
25. Never Block The Event Loop
26. RethinkDB in Node.js npm install rethinkdb
27. Querying RethinkDB const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").run(conn,(err, cursor)=> { cursor.toArray((err, results) => { conn.close(); console.log(results); }) }) })
28. Querying RethinkDB const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").run(conn,(err, cursor)=> { cursor.toArray((err, results) => { conn.close(); console.log(results); }) }) })
29. Querying RethinkDB const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").run(conn,(err, cursor)=> { cursor.toArray((err, results) => { conn.close(); console.log(results); }) }) })
30. Querying RethinkDB const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").run(conn,(err, cursor)=> { cursor.toArray((err, results) => { conn.close(); console.log(results); }) }) })
31. Changefeeds are similar... const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").changes() .run(conn,(err, cursor)=> { cursor.each((err, event) => { console.log(event) }) }) })
32. Changefeeds are similar... const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").changes() .run(conn,(err, cursor)=> { cursor.each((err, event) => { console.log(event) }) }) })
33. Changefeeds are similar... const r = require("rethinkdb"); r.connect((err, conn) => { r.table("questions").changes() .run(conn,(err, cursor)=> { cursor.each((err, event) => { console.log(event) }) }) })
34. Putting everything together
35. App GET /questions POST /question App App App App RethinkDB
36. App .changes() io.emit('new', q) RethinkDB App App App App io.emit('new', q) io.emit('new', q) io.emit('new', q) io.emit('new', q)
37. Socket.IO npm install socket.io
38. r.table("questions").changes() .run(conn, (err,cursor) => { cursor.each((err, e) => { if (!e.old_val && e.new_val) { io.emit('new-q', e.new_val) } }); });
39. <script src="/socket.io/socket.io.js"></script> <script> var socket = io(); io.on('new-q', q => { // do something with this data }) </script>
40. www.rethinkdb.com www.nodejs.org www.compose.com http://bit.ly/2ciJ17Y
41. Demo