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20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
20120802 timisoara
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20120802 timisoara

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  • Transcript

    • 1. Node.js &Mobile Apps Richard Rodger @rjrodger nearform.com
    • 2. •Why should you use Node.js?•Node.js basics•Lessons from a real world project
    • 3. nodejs.org• Code in JavaScript on the server• Built using Chrome V8 Engine - so its really fast!• Everything is event-based; there are no threads
    • 4. Node.js Web Servervar http = require(http);var server = http.createServer( function(req, res) { res.writeHead(200, {Content-Type: text/plain}) res.end(Hello Worldn)});server.listen(80, 127.0.0.1);console.log(Web server running at http://127.0.0.1:80);
    • 5. why?
    • 6. there arethreeeras... 1990s 2000s 2010s
    • 7. "keep your job" Node.js is languages the platform * yes I know about tiobe.com
    • 8. how manyconcurrent clients? 90s: 10 00s: 100 10s: 1000 C10K Problem
    • 9. How doyou scale? processes threads events
    • 10. JavaScript: the worlds ugliest language avoid slow, validate forms date ECMA, jQuery marry Node.js, Crockford
    • 11. Wherewill yourapp live? co-lo buy, build, and rack IaaS Amazon EC2 PaaS Heroku
    • 12. DontForget the Webbrowser wars web 2.0 standardise!
    • 13. Mobile Hybrid Native Web HTML5/JS Gotta learn em all*HTML5/JS
    • 14. Mobile Web Apps• Web Pages built using HTML5 features: • Canvas for drawing • In-built Video and Audio • Geolocation • Web Sockets • Local Storage, Local Caching • CSS3 transitions (not really HTML5)• Use JavaScript as main programming language ft.com business• Designed for Touch Interfaces post.ie • Smart phone or Tablet form factors • Don’t use Hover effects, instead convey touch affordance using 3D styling• Dynamic single page apps. Changes are made to the HTML rather than loading new pages.
    • 15. Mobile Web Standards ComplianceLatest Versions Storage CSS3 Mobile Multimedia local, cache, sql effects, 2D, 3D touch, geo & motion video & audio iOS ★★★ ★★★ ★★★ ★★ Android ★★★ ★★★ ★★★ ★ Win Ph. 7 ★ ★★ ★ ★BlackBerry 6+ ★★ ★★ ★★ ★ Legacy recent Nokias ★ ★ ★ mobilehtml5.org
    • 16. Node.js and Mobile 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
    • 17. • Runs high-performance server-side JavaScript • open source, sponsored by joyent.com• 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
    • 18. being event-driven is likehaving a butler run yourserver
    • 19. Your code runs in one thread only!
    • 20. Working with Events var http = require(http); var server = http.createServer(); server.on( request, function(req, res) { res.writeHead(200, {Content-Type: text/plain}) var echo = req.on(data,function(chunk){ echo += chunk }) req.on(end, function(){ res.end( echo+n ) }) req.on(error, function(err){ res.end( "error: "+err ) }) }) server.listen(80, 127.0.0.1); console.log(try: curl http://127.0.0.1 -d hello);
    • 21. What does the core API give you? Q basics: file system, ... 9 control: events, streams, buffers... g networking: sockets, DNS, ... „ web server: HTTP handling, ...
    • 22. Node.js modules are so cool• Easy syntax • var moduleAPI = require("modulename");• Central repository • npmjs.org• Easy command line install • npm install modulename• No version conflicts! • intelligent dependency management• Declarative project description • package.json file goes into project root folder
    • 23. Some important modules(find them on npmjs.org or github.com)• connect • HTTP middleware infrastructure - requests pass through layers• express • JSP/ASP style dynamic server-side pages• underscore • same as client-side library! provides functional utilities: map, reduce, ...• socket.io • HTML5 real-time web sockets that "just work" - includes client-side API• request • easy outbound calls to web services
    • 24. Node.js is It doesntoverhyped matter • Not a clear winner against • Chrome V8 Engine means Node.js is "Good Enough" other event servers on speed • Asynchronous code is harder • JavaScript means almost all libraries are asynchronous, unlike than synchronous code other event servers • No, you wont re-use much • JavaScript is a local maximum and code between client and youre stuck with it server • Same language on client and server makes your brain happy • Memory can still leak • Compile to JavaScript if you really • Its not a mature platform hate the language
    • 25. businesspost.ie
    • 26. Web Mobile Cloud ServicesWeb Apps Services API Mobile & REST & DatabaseTablet Web JSON Mobile & Horizontal Third PartyTablet Apps Scale Services Desktop Cloud Monitoring Web Hosted
    • 27. 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
    • 28. 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
    • 29. Cloud ServicesDatabase Hosting MonitorsMongoDB Amazon Amazon Load Redis cloudkick Balancer Instancememcached Continuous Scaling
    • 30. Third Party IntegrationJSON, 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
    • 31. Native AppsSame code as mobile web versions, ... ... wrapped using PhoneGap to run natively ... plus some native plugins
    • 32. Lesson:
    • 33. Lesson: code volume43210 Client JavaScript Server JavaScript
    • 34. 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
    • 35. 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
    • 36. Lesson:the app stores are not web sites • that bug in version 1... • you cant 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
    • 37. 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 • Dont do CPU intensive stuff • < 100ms startup time • ... theres a warning on • means you may not the tin! notice!
    • 38. 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)
    • 39. Node.js means Rapid Development * Bruno Fernandez-Ruiz http://www.olympum.com/architecture/the- nodejs-innovation-advantage/
    • 40. My CompanyMobile Apps + Node.jsMy Bookrichardrodger.comRichard Rodger@rjrodgernearform.com

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