node js express: steps to create restful web app

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View Mastering Node.js course details at www.edureka.co/mastering-node-js

Node JS Express - Steps to create Restful Web App

http://www.edureka.co/mastering-node-js


LIVE Online Class

Class Recording in LMS

24/7 Post Class Support

Module Wise Quiz

Project Work

Verifiable Certificate

Course Features


Objectives

At the end of the session you will be able to learn:

NPM

Node.js Express

Templates in Express

Creating Restful Web App

www.edureka.co/mastering-node-jsSlide 4

What is Node.js ?

Node.js is an open source, cross-platform runtime environment for server-side and networking applications

Node.js applications are written in JavaScript, and can be run within the Node.js runtime on OS X, Microsoft

Windows, Linux, FreeBSD, NonStop and IBM. -- Wikipedia

This is based on Google’s V8 JavaScript Engine


What is Node.js ? (Contd.)

Guess What ?

» IT’s SINGLE THREADED !!

» No worries about : race conditions, deadlocks and other problems that go with multi-threading.

» “Almost no function in Node directly performs I/O, so the process never blocks. Because nothing blocks,

less-than-expert programmers are able to develop scalable systems.” - (courtesy : nodejs.org)

Event Loop

Event Queue

Thread Pool

file system

network

process

other


Basics of Node.js : npm

npm used to stand for Node Package Manager. However it is not an acronym anymore. npm is not a Node.js

specific tool

npm is a registry of reusable modules and packages written by various developers

» Yes, you can publish your own npm packages

There are two ways to install npm packages :

» Locally : To use and depend on the package from your own module or project

» Globally: To use across the system, like a command line tool


Use-Cases of Node.js

1. Walmart executives believe that the benefit of using Node.js wasfar greater than any risk in adopting a new technology

2. They re-engineered their mobile app to run on Node.js where allthe front end code gets executed on back-end

3. “We rely on services all over the world,” says Almaer (V.P MobileArchitecture) “We do not control all of those services. Nodeallows us to front all these services… and scale up very nicely.It’s perfect for what we’re doing in mobile.”

Server Side Web Applications 1. Server Side Web Applications

Advantages


Use-Cases of Node.js (Contd.)

1. Linkedin is also leaning heavily on Node.js (Linkedin mobile and tablet app is 95% html/web based)

2. “We’re still full-on Node. We are excited that it can scale,” says Kiran Prasad (Head of Linkedin’s Mobile Development Team). “Over the past few months, we’ve made performance tweaks so we can scale even more. On four boxes, we can now handle 20 times the load we were handling before.”

Highly Scalable

1. Server Side Web Applications

2. Highly Scalable

Advantages


Use-Cases of Node.js (Contd.)

1. When he first built Voxer, Matt Ranney (Voxer’s CTO) ran a test to see how many connections he could open on a single server. "I just decided to open as many connections as I could, just to see where things would fall down," Ranney says

2. "With Node, I could open, well, all of them. I couldn't open any more connections without getting more IP addresses on my test machine. Node uses such small amounts of memory, it's astounding. I ran out of port numbers."

Low Memory Consumption

1. Server Side Web Applications

2. Highly Scalable

3. Low Memory Consumption

Advantages


Express JS

Express JS : Web Framework for Node.js. It is an npm package

To install : npm install -g express //in the main project folder

Express JS also provides a tool to create a simple folder structure for your app :

» Now, saying express newapp will create a project called newapp in the current working directory along

with a simple folder structure.

» The dependencies will then be installed by doing a cd newapp and then npm install

» To run the app

» node app // This is where the server is run and listening on a port


Express JS : Templates

By default Express supports the Jade Template Engine for the HTML Views.

What is an Javascript Template Engine : it is a framework to help bind data to your HTML views

Why do you need one ?

» Helps you easily bind data from the back end with the HTML view

» Helps in bundling HTML code into reusable modules/layouts

» Adds basic conditionals & iterations / loops to your HTML. HTML does not support “If -Else” or “for”

loops.

Many Javascript Template Engines are available : Jade, Handlebars, Hogan, EJS, etc.


Express JS : Jade

Jade is a simple Javascript Template engine for writing HTML. No config has to be set up for ExpressJS

since it is the default view engine

It supports dynamic code, template inheritance and allows you to compile templates into reusable

functions that can run on server

Example of Jade syntax :

JADEhtml

headtitle My App Title

body h1= pageHeaderVardiv.className

p. some

content

HTML<html>

<head><title> My App Title

</title></head><body>

<h1>Page Header</h1><div class=”className”>

<p>some

content</p>

</div></body>

</html>


Express JS : A Simple Express Application

var express = require(‘express’);

var app = express();

app.get(‘/’,function(req,res){

res.send(‘Hello World !!”);

})

app.listen(3000,function(){

console.log(‘Express Server listening on port 3000);

})


Job Trends

Salaries for Node.js Developers are already in the $60,000 range and much more.

From the graph below : The number of jobs are skyrocketing.


DEMO


Course Topics

→ Module 7

» Forks, Spawns and the Process Module

→ Module 8

» Testing in Node.js

→ Module 9

» Node.js in the Tech World

→ Module 1

» Introduction to Objects in Javascript & Node.js

→ Module 2

» Modules / Packages

→ Module 3

» Events & Streams

→ Module 4

» Network Communication & Web Technology in Node.js

→ Module 5

» Building a Web Application

→ Module 6

» Real-time Communication


Questions