Introduction to node.js GDD

Introduction to Node.js Sudar Muthu (@sudarmuthu) Research Engineer Yahoo! Labs http://github.com/sudar http://sudarmuthu.com

Agenda What Node.JS is not What is Node.JS Why Node.JS? Using Node.JS › As a interactive shell › As a Server › As a Client Common Modules Terminologies Workshop

Node.JS is not … Ruby on Rails Django Codeigniter CakePHP Node.JS is bare bone and the community are making stuff like Express, connect etc.

What is Node.JS JavaScript Programming Environment for creating highly scalable network programs Provides Evented, non-blocking I/O Built on top of V8 engine Supports C/C++ based addons Supports CommonJS Module format Is fast .. in fact very fast. Similar to Event machine in Ruby or Twisted in Python

What is Evented I/O

Single thread Synchronous I/O

Multi thread Synchronous I/O

You can throw in more servers, but that will cost you lot of money.

Synchronous I/O

Single thread Asynchronous I/O

Why Node.JS?So, code like thisvar result = db.query("select..");// use resulteither blocks the entire process orimplies multiple execution stacks (threads).

Why Node.JS?But code like thisdb.query("select..", function (result) { // use result});allows the program to return to the event loop immediately. No more unnecessary threads.

Demo of Callback// execute the callback after 2 secondssetTimeout(function () { console.log("World!");}, 2000);// print in consoleconsole.log("Hello");https://github.com/sudar/node.js-samples/blob/master/callback.js

Using Node.JS Install Node.JS Install NPM Install other modules you want by doingnpm install <module_name> You are good to go(This setup is already done for you. Use the Ubuntu image in thepen drive)

Node.JS – as an interactive shellSimilar to Python’s shell$> node>3+14> true != falsetrue>.help>.exit

Node.JS – As a servervar http = require(http); // require the http module// create a serverhttp.createServer(function (req, res) { // call this function when a request is received res.writeHead(200, { Content-Type: text/plain }); // send this as part of the response res.end(Hello Worldn);}).listen(1337, "127.0.0.1"); // listen on port 1337// debug informationconsole.log(Server running at http://127.0.0.1:1337/);https://github.com/sudar/node.js-samples/blob/master/http-server.js

Node.JS – As a clientvar http = require(http); // require the needed modules// make the request objectvar request = http.request({ host: sudarmuthu.com, port: 80, path: /, method: GET});// assign callbacksrequest.on(response, function (response) { console.log(Response Status Code: + response.statusCode); response.on(data, function (data) { console.log(Body: + data); });});https://github.com/sudar/node.js-samples/blob/master/http-client.js

Core Modules Processes Filesystem Networking UtilitiesThe entire list can be found at http://nodejs.org/api/

Core Modules - ProcessesNode allows you to analyze your process and manage external processAvailable Modules process child_processCode samples: https://github.com/sudar/node.js- samples/blob/master/process.js

Core Modules - FilesystemLow level API to manipulate filesAvailable Modules fs pathCode Samples: https://github.com/sudar/node.js- samples/blob/master/filesystem.js

Core Modules - Networking Available Modules  net  dgram  http  tls  https  dns Code Samples: https://github.com/sudar/node.js- samples/blob/master/dns.js

Core Modules - Utilities Provides utility methods Available Modules  console  util Code Samples: https://github.com/sudar/node.js- samples/blob/master/console.js

Node.JS is useful for.. Writing highly concurrent server applications Sharing application logic between server and client Peer-to-peer web applications using websockets Real-time applications

Terminologies NPM – Package manager (like apt-get) Modules – Plugins or add-ons for Node.JS Express – MVC framework (like RoR) Jade – Template Engine (like Smarty) Socket.IO – A websockets Library

Links http://github.com/sudar/node.js-samples (all code samples used in this talk) http://nodejs.org http://npmjs.org http://expressjs.com http://socket.io

Workshop

Express JS Basic web framework Runs on top of node.js Provides routing and redirection helpers Dynamic view helpers Has support for sessions Focus on high performance

Hello World Express Apphttps://github.com/sudar/node.js-samples/tree/master/express/hello-world

Square Things App Allows you to choose the color of a square region A very simple server implementation A very simple client MVC implementation Uses node.js on the server Uses Y.App implementation on the clienthttps://github.com/ericf/square-thing-app

Thank you

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Introduction to node.js GDD

by Sudar Muthu on Jun 16, 2012

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