Express : Fast, unopinionated, minimalist web framework for node.

var express = require(express)
var app = express()
 
app.get(/, function (req, res) {
  res.send(Hello World)
})
 
app.listen(3000)

Installation

$ npm install express

Features

  • Robust routing
  • Focus on high performance
  • Super-high test coverage
  • HTTP helpers (redirection, caching, etc)
  • View system supporting 14+ template engines
  • Content negotiation
  • Executable for generating applications quickly

Docs & Community

PROTIP Be sure to read Migrating from 3.x to 4.x as well as New features in 4.x.

Security Issues

If you discover a security vulnerability in Express, please see Security Policies and Procedures.

Quick Start

The quickest way to get started with express is to utilize the executable express(1) to generate an application as shown below:

Install the executable. The executable’s major version will match Express’s:

$ npm install -g express-generator@4

Create the app:

$ express /tmp/foo && cd /tmp/foo

Install dependencies:

$ npm install

Start the server:

$ npm start

Philosophy

The Express philosophy is to provide small, robust tooling for HTTP servers, making it a great solution for single page applications, web sites, hybrids, or public HTTP APIs.

Express does not force you to use any specific ORM or template engine. With support for over 14 template engines via Consolidate.js, you can quickly craft your perfect framework.

Examples

To view the examples, clone the Express repo and install the dependencies:

$ git clone git://github.com/expressjs/express.git –depth 1
$ cd express
$ npm install

Then run whichever example you want:

$ node examples/content-negotiation

Tests

To run the test suite, first install the dependencies, then run npm test:

$ npm install
$ npm test

How to Install Latest Nodejs & Npm on Ubuntu 16.04 & 14.04

Node.js is a platform built on Chrome’s JavaScript runtime for easily building fast, scalable network applications. Latest version node.js ppa is maintaining by its official website. We can add this PPA to Ubuntu 16.04 LTS (Trusty Tahr) and 14.04 LTS (Xenial Xerus) Systems and install node.js with few easy commands.

Install nodejs

Step 1: Add NodeJs PPA

First, you need to node.js PPA in our system provides by nodejs official website. We also need to install python-software-properties package if not installed already.

$ sudo apt-get install python-software-properties
$ curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash -

Step 2: Install Nodejs and NPM

After adding required PPA file lets install Node package. NPM will also be installed with node.js. This command will also install many other dependent packages on your system.

$ sudo apt-get install nodejs

Step 3: Check Node.js and NPM Version

After installing node.js verify and check the installed version. You can find more details about current version on node.js official website.

$ node -v 

v7.10.0

Also, check the version of installed npm.

$ npm -v 

4.2.0

Step 4: Create Demo Web Server (Optional)

This is an optional step. If you want to test your node.js install. Let’s create a web server with “Hello World!” text. Create a file http_server.js

$ vim http_server.js

and add following content

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(3001, "127.0.0.1");
console.log('Server running at http://127.0.0.1:3001/');

Now start the web server using below command.

$ node --debug http_server.js

debugger listening on port 5858
Server running at http://127.0.0.1:3001/

The web server has been started on port 3001. Now access http://127.0.0.1:3001/ URL in browser. Now you will need to configure a front-end server for your app.

 

credit : https://tecadmin.net/