Introducción y comandos en NodeJS slodte
- 1. Introduction to Node.js® Jitendra Kumar Patel Saturday, January 31, 2015
- 2. Why node.js ? “Node's goal is to provide an easy way to build scalable Network programs”
- 3. • Created by Ryan Dahl in 2009 • Development && maintenance sponsored by Joyent • Licence MIT • Last release : 0.10.31 • Based on Google V8 Engine • +99 000 packages About Node.js……
- 5. ● Vert.x => Polygot programming ● Akka => Scala and Java ● Tornado => Python ● Libevent => C ● EventMachine => Ruby Another project like Node.js….
- 6. ● Another Web framework ● For beginner ● Multi-thread Node.js not……
- 7. • Traditional desktop applications have a user interface wired up with background logic – user interfaces are based on Windows Forms, Jswing, WPF, Gtk, Qt, etc. and dependant on operating system • On the web user interfaces are standardized – HTML for markup – CSS for style – JavaScript for dynamic content • In the past proprietary technologies existed on the web, e.g. Adobe Flash, ActiveX – They are slowly dying • Data is generated on the server, transferred to the client and displayed by the browser • Server Side technologies include PHP, JSP, ASP.net, Rails, Djanog, and yes, also node.js Development for the Web….
- 8. ● REST = REpresentational State Transfer ● Not new technology ● Architectural style for client-server REST……
- 9. ● General interface ● Scalability of component interface ● Reduce latency ● Encapsulate legacy system Goals of REST……..
- 10. ● GET ● POST ● PUT ● DELETE HTTP Method……
- 11. ● POST => Create ● GET => Read ● PUT => Update ● DELETE => Delete HTTP Method with CRUD…..
- 12. ● Non Blocking I/O ● V8 Javascript Engine ● Single Thread with Event Loop ● 40,025 modules ● Windows, Linux, Mac ● 1 Language for Frontend and Backend ● Active community Why node.js ?
- 13. • Asynchronous i/o framework • Core in c++ on top of v8 • Rest of it in javascript • Swiss army knife for network Related stuffs • Can handle thousands of Concurrent connections with Minimal overhead (cpu/memory) on a single process • It’s NOT a web framework, and it’s also NOT a language What is node.js? « A platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. » http://nodejs.org/
- 14. • Friendly callbacks • Ubiquitous • No I/o Primitives • One language to RULE them all JavaScript is well known for client-side scripts running inside the browser node.js is JavaScript running on the server-side SSJS -> Server-Side JavaScript Use a language you know Use the same language for client side and server side Why javascript ?!!!
- 16. Perform asynchronous processing on single thread instead of classical multithread processing, minimize overhead & latency, maximize scalability Scale horizontally instead of vertically Ideal for applications that serve a lot of requests but dont use/need lots of computational power per request Not so ideal for heavy calculations, e.g. massive parallel computing Also: Less problems with concurrency The idea behind node.js….
- 17. Node.js Event Loop There are a couple of implications of this apparently very simple and basic model • Avoid synchronous code at all costs because it blocks the event loop • Which means: callbacks, callbacks, and more callbacks
- 18. Example :: Read data from file and show data Blocking vs Non-Blocking……
- 19. ● Read data from file ● Show data ● Do other tasks var data = fs.readFileSync( “test.txt” ); console.log( data ); console.log( “Do other tasks” ); Blocking…..
- 20. ● Read data from file When read data completed, show data ● Do other tasks fs.readFile( “test.txt”, function( err, data ) { console.log(data); }); Non-Blocking…… Callback
- 21. • Chat/Messaging • Real-time Applications • Intelligent Proxies • High Concurrency Applications • Communication Hubs • Coordinators When to use it ?
- 22. ● Web application ● Websocket server ● Ad server ● Proxy server ● Streaming server ● Fast file upload client ● Any Real-time data apps ● Anything with high I/O Node.js for….
- 23. • http://nodejs.org/ and Download tar.gz • Extract to any directory • $ ./configure && make install Getting Started…..
- 24. Project informations • Name • Version • Dependencies • Licence • Main file Etc... File package.json…..
- 25. ● https://npmjs.org/ ● # of modules = 1,21,943 Node.js Modules…..
- 26. $npm install <module name> Install module…..
- 27. • var http = require(‘http’); • var fs = require(‘fs’); • var express = require(‘express’); Using module…..
- 28. In NodeJS
- 30. ● express ● underscore ● request ● async ● mysql Find more in npmjs.org….. Favorite Modules…..
- 31. • IDEs for node.js – online IDE like cloud9 – Eclipse with node.js plugins – Visual Studio node.js Toolkit – Jetbrains Webstorm – lots of other IDEs: webmatrix, coderunner, Expresso, Atom, etc. • Preferred : Jetbrains Webstorm & Visual Studio with node.js Tools of the trade…..
- 33. Middleware can: • Execute any code. • Make changes to the request and the response objects. • End the request-response cycle. • Call the next middleware in the stack. Express As Middleware
- 35. ● Inspire from Sinatra ● Fast ● Flexible ● Simple Working with Express…..
- 36. • Release stable 0.10.36 (young) • Lots of stuffs to look at • Lots of half backed stuffs • Retro compatibility??? • Bad at handling staticcontents • Bad at handling binarycontents • Hard to find organized and authoritative informations Some Warnings…