© 2014 IBM Corporation Empowering the IBM ecosystem Introduction to Developing applications using node.js on Bluemix IBM Ecosystem Development Instructors : – Krishnaprasad Subbarao, Abhay Ratnaparkhi

© 2014 IBM Corporation Empowering the IBM ecosystem Introduction to node.js – What is node.js – node.js first app – Components of node.js – node.js api – node.js modules – Express – npm Developing a node.js application on Bluemix – IBM DevOps Services for Bluemix Developing IOT application on Bluemix Agenda

© 2014 IBM Corporation Empowering the IBM ecosystem open source, cross-platform runtime environment for server-side and networking applications Server side Java script system applications are written in JavaScript, and can be run within the Node.js runtime. contains a built-in library to allow applications to act as a Web server Powered by Google 8 runtime provides an event-driven architecture and a non-blocking I/O API commonly used for real-time web applications. What is node.js

© 2014 IBM Corporation Empowering the IBM ecosystem Download link : First program HelloWord.js var http = require('http'); http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World\n'); }).listen(1337, " "); console.log('Server running at Cmd> node HelloWorld.js Server running at node.js first app

© 2014 IBM Corporation Empowering the IBM ecosystem node.js : Components

© 2014 IBM Corporation Empowering the IBM ecosystem Application : the user developed application Java script : prototype based scripting language V8 Javascript Engine : – Open source javascript engine developed by Google – Used by Chrome, Node.js Bindings : programs that make V8 and the library able to talk to each other. – e.g. binding for database libraries – node-js/ node-js/ node.js Components continued..

© 2014 IBM Corporation Empowering the IBM ecosystem LIBUV : – a multi-platform support library – focuss on asynchronous I/O – primarily developed for use by Node.js – also used by Luvit, Julia, pyuv and few others – Event loop Non thread safe Handles – long lived objects e.g. a TCP server handle – Call backs are called when an event occurs Requests – Short lived operations run directly on the loop node.js Components continued..

© 2014 IBM Corporation Empowering the IBM ecosystem Provides large number of built in functions, modules, add ons HTTP – provides a way to develop an http server which can process http requests Globals – require : A reference to a function used to require modules. – module : A reference to the current module – exports :A reference to the module.exports variable – console : For printing to stdout and stderr. node.js api

© 2014 IBM Corporation Empowering the IBM ecosystem A Node/npm module is just an simple JavaScript file follows the CommonJS module spec. encapsulates related code into a single unit of code Allows building re-usable code Samples modules : http, express node.js modules

© 2014 IBM Corporation Empowering the IBM ecosystem // greetings.js sayHelloInEnglish = function() { return "Hello"; }; sayHelloInSpanish = function() { return "Hola"; }; node.js modules continued..

© 2014 IBM Corporation Empowering the IBM ecosystem // greetings.js // var exports = module.exports = {}; exports.sayHelloInEnglish = function() { return "HELLO"; }; exports.sayHelloInSpanish = function() { return "Hola"; }; node.js modules continued..

© 2014 IBM Corporation Empowering the IBM ecosystem // main.js var greetings = require("./greetings.js"); Equivalent to var greetings = { sayHelloInEnglish: function() { return "HELLO"; }, sayHelloInSpanish: function() { return "Hola"; } }; node.js modules continued..

© 2014 IBM Corporation Empowering the IBM ecosystem Express : – minimal and flexible Node.js web application framework – provides a robust set of features for web and mobile applications. – – Provides 4 objects Application - app – holds the settings of the express application HTTP request – req – provides a way to read all the request parameters, query string, request body for POST requests Express

© 2014 IBM Corporation Empowering the IBM ecosystem Express : – Objects HTTP response - res – provides ways to return the response back to the client. Router – Router – accepts a set of functions attached to a path – executed when a request for the attached path or any inner path is received Express continued..

© 2014 IBM Corporation Empowering the IBM ecosystem HelloWorldExpress.js var express = require('express') var app = express() app.get('/', function (req, res) { res.send('Hello World!') }) var server = app.listen(3000, function () { var host = server.address().address var port = server.address().port console.log('Example app listening at host, port) }) Express continued..

© 2014 IBM Corporation Empowering the IBM ecosystem pre-installed package manager for the Node.js server platform. It is used to install Node.js programs from the npm registry npm init - creates a new package npm install e.g. npm install express –save – Install express and adds to package.json npm

© 2014 IBM Corporation Empowering the IBM ecosystem Contains complete structure of the application. – all packaging, dependency and version related information. important contents – main : module ID that is the primary entry point to your program – License : license information of the module. – man : to specify the help contents about this package – config : to set configuration parameters used in package scripts – Dependencies : list modules on which this module is dependent Package.json

© 2014 IBM Corporation Empowering the IBM ecosystem { "name": "samples", "version": "1.0.0", "description": "Node.js introduction samples", "main": "HelloWorld-express.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "license": "ibm", "dependencies": { "express": "^4.11.0" } Package.json

© 2014 IBM Corporation Empowering the IBM ecosystem Developing a node.js application on Bluemix