20120306 dublin js
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The document discusses how JavaScript can be used from the user interface on mobile and web apps through to the server and database using techniques like Node.js. It provides examples of how Node.js allows for high performance server-side JavaScript and how MongoDB can be used as a database. The document outlines lessons learned around challenges of multi-platform development and benefits of outsourcing databases and other services.
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20120306 dublin js
- 1. JavaScript End-to-End Touch-screen to Server Richard Rodger @rjrodger
- 2. What can JavaScript do for you? How does it work? A real life example Lessons learned
- 3. User Interface Complex, Stateful, Interactive
- 5. Hybrid Apps HTML5/JS in a Native Wrapper
- 7. Database Map Reduce (was Stored Procedure) http://blog.sharpthinking.com.au
- 8. Web Service APIs JSON & XML, REST & SOAP
- 9. Real-Time Web Web Sockets Web sockets are so cool ... you never have to hang up
- 10. How? •User Interface frameworks •Multi-Device html5 •Hybrid Apps phonegap •Server-Side node.js •Database mongodb, couchdb •Web Services node.js modules •Real-Time Web socket.io
- 11. Basic Idea nginx Node.js • nginx • high performance web server • serves static resources: test files, images • proxies requests through to Node.js app server • Node.js • high performance server-side JavaScript • Executes business logic and database queries
- 12. Node.js • Runs high-performance server-side JavaScript • Uses the Google Chrome V8 engine • just-in-time compilation to machine code • generation garbage collection (like the Java JVM) • creates virtual “classes” to optimise property lookups • Has a well-designed module system for third party code - very effective and simple to use • Your code runs in a single non-blocking JavaScript thread • That’s OK, most of the time you’re waiting for database or network events
- 13. Node.js Web Server var http = require('http'); var server = http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello Worldn'); }) server.listen(1337, "127.0.0.1"); console.log('Server running at http://127.0.0.1:1337');
- 14. businesspost.ie
- 15. Web Mobile Cloud Services Web Apps Services API Mobile & REST & Database Tablet Web JSON Mobile & Horizontal Third Party Tablet Apps Scale Services Desktop Cloud Monitoring Web Hosted
- 16. Client-side Router #! URLs • Common code-base • even for hybrid apps! Models Data, biz logic • backbone.js • shims for weak browsers Views DOM Layout • browser-targeting: user- agent & capabilities • responsive layout (mostly) Helpers Shared code
- 17. Client-side: running 1. Load static 2. Init shared index.html code, then 3. Init and assets targeted router, and 4. Wait for code display as events per #! URL
- 18. Server-side map /api/ URLs • nginx & Node.js Router to functions • Small code volume API function( req, • Third party modules: functions res ) { ... } • connect Shared code • express Helpers (some with client) • seneca (my db layer) Open source • Deploy with: Modules heavy-lifting • sudo killall node
- 19. Server-side: running 1. Connect to databases 2. Route and listen HTTP 3. Talk to for HTTP requests to database, 4. Send API functions wait for JSON back callback to client
- 20. Cloud Services Database Hosting Monitors MongoDB Amazon Amazon Load Redis cloudkick Balancer Instance memcached Continuous Scaling
- 21. Third Party Integration JSON, XML, simple form data, text files, ... ... all easy using JavaScript and Node.js Modules Analytics Twitter E-Commerce In-App Logging Facebook Purchasing Email LinkedIn Stock Feed
- 22. Native Apps Same code as mobile web versions, ... ... wrapped using PhoneGap to run natively ... plus some native plugins
- 23. Lesson:
- 24. Lesson: code volume 4 3 2 1 0 Client JavaScript Server JavaScript
- 25. Lesson: multi-platform client-side JavaScript is really hard • a framework is a must • code against ECMA, use shims to support older browsers • backbone.js • Code/Test/Debug inside Safari • business logic must be in • phonegap.github.com/weinre common code for hard to reach places • browser-specific code • use error capture in production • virtual .js files • Finally, use a simple static site as a fallback (also for Googlebot) • use jshint to keep IE happy
- 26. Lesson: multi-platform HTML/CSS is really hard • "structured" CSS is a must • Clean, semantic HTML is not optional • sass or less • graceful degradation may • Be happy with require radically different CSS • media queries • 100% "Responsive" design is tough • CSS3 transforms • Responsive within browser subsets has higher reward/ • browser-specific code effort • virtual .css files
- 27. Lesson: the app stores are not web sites • that bug in version 1... • you can't deploy hot fixes • will take two weeks to • make everything fix via an update configurable! • some users will never • All prices, text, host update names, urls, ... • appears after an OS • On launch, app "checks-in" update for new configuration • this will save your life
- 28. Lesson: Node.js does what it says on the tin • High performance • callback spaghetti is not a problem in practice • High throughput • Low CPU usage • use functional style • Constant memory usage • client-side code is far more difficult • leaks will kill, but then • Don't do CPU intensive stuff • < 100ms startup time • ... there's a warning on • means you may not the tin! notice!
- 29. Lesson: Outsource your database • Remote MongoDB • Big productivity gain hosting • no production tuning • mongohq.com • no configuration • No downtime • no cluster set up • Backups • Low latency (in Amazon) • Web-based admin (if lazy)
- 31. My Company HTML5 Apps + Node.js My Book Launch: Hodges Figgis 21st March, 7:30 PM Richard Rodger @rjrodger nearform.com
- 32. My Company HTML5 Apps + Node.js My Book Launch: Hodges Figgis 21st March, 7:30 PM Richard Rodger @rjrodger nearform.com