Nodejs presentation

Nodejs presentation

• 1.
  The Server-side JavaScript
• 2.
  AGENDA  Introduction  NodeJS –Asynchronous nature  MongoDB – Data Model – JSON based storage – Querying
• 3.
  BACKGROUND  V8 isan open source JavaScript engine developed by Google.  Node.js runs on V8  It was created by Ryan Dahl in 2009.  Is Open Source. It runs well on Linux systems, can also run on Windows systems. Similar to EventMachine (Ruby) or Python’s Twisted or Perl’s AnyEvent
• 4.
  INTRODUCTION: BASIC  Insimple words Node.js is ‘server-side JavaScript’.  In not-so-simple words Node.js is a high- performance network applications framework, well optimized for high concurrent environments. ‘Node's goal is to provide an easy way to build scalable network programs’ - (from nodejs.org!)
• 5.
  GETTING STARTED &HELLO WORLD  Install/build Node.js.  When you are done, open cmd/terminal and type this: ‘node YOUR_FILE.js’ Here is a simple example, which prints ‘hello world’ var sys = require(“sys”); sys.puts(“hello”);
• 6.
  SOME THEORY: NON-BLOCKINGI/O  Traditional I/O var result = db.query(“select x from table_Y”); doSomethingWith(result); //wait for result! doSomethingWithOutResult(); //execution is blocked!  Non-traditional, Non-blocking I/O db.query(“select x from table_Y”,function (result) { doSomethingWith(result); //wait for result! }); doSomethingWithOutResult(); //executes without any delay!
• 7.
  WHAT CAN YOUDO WITH NODE.JS ?  You can create an HTTP server and print ‘hello world’ on the browser in just 4 lines of JavaScript. (Example included)  You can create a TCP server similar to HTTP server, in just 4 lines of JavaScript. (Example included)  You can create a DNS server.  You can create a Static File Server.  You can create a Web Chat Application like GTalk in the browser.  Node.js can also be used for creating online games, collaboration tools or anything which sends updates to the user in real-time.
• 8.
  WHEN TO USENODE.JS?  Node.js is good for creating streaming based real-time services, web chat applications, static file servers etc.  If you need high level concurrency and not worried about CPU-cycles.  If you are great at writing JavaScript code because then you can use the same language at both the places: server-side and client-side.
• 11.
  Java IO
• 12.
  NODEJS
• 13.
  RESOURSCE TO GETSTARTED  Watch this video at Youtube: http://www.youtube.com/watch?v=jo_B4LTHi3 I  Read the free O’reilly Book ‘Up and Running with Node.js’ @ http://ofps.oreilly.com/titles/9781449398583/  Visit www.nodejs.org for Info/News about Node.js  Watch Node.js tutorials @ http://nodetuts.com/  For Info on MongoDB: http://www.mongodb.org/display/DOCS/Home  For anything else Google!
• 14.
  SOME GOOD MODULES Express – to make things simpler e.g. syntax, DB connections.  Jade – HTML template system  Socket.IO – to create real-time apps  Nodemon – to monitor Node.js and push change automatically  CoffeeScript – for easier JavaScript development  Find out more about some widely used Node.js modules at: http://blog.nodejitsu.com/top-node-module-cr eators
• 15.
  EXAMPLE: LETS CONNECTTO A DB (MONGODB)  Install mongojs using npm, a mongoDB driver for Node.js npm install mongojs  Code to retrieve all the documents from a collection: var db = require("mongojs") .connect("localhost:27017/test", ['test']); db.test.find({}, function(err, posts) { if( err || !posts) console.log("No posts found"); else posts.forEach( function(post) { console.log(post); }); });
• 16.
  JSON OVERVIEW  Similarto XML – lightweight –  JavaScript Objects – Natively parseable by JS (eval)  AJAX - Language for REST based API design