This document provides an introduction to Node.js and creating simple web applications. It outlines downloading and installing Node.js, then creating a basic "Welcome" application that logs text to the console. Next, it shows how to create an HTTP server that hosts the "Welcome" text at localhost:9000, so it can be viewed in a web browser. The server code is explained, including requiring the HTTP module, creating the server object, handling requests and responses, setting response headers, and listening on port 9000. Finally, it promises more advanced Node.js topics and examples in future sessions.

1. NODE.JS
Day ­ 1
Soni Pandey
Software Developer

2. Download the Node.js for your operating system and
install.
https://nodejs.org/download/
Installation

3. Welcome ApplicationFirst, we will console text “Welcome !!”. We will make welcome.js
file. Welcome.js
console.log(“Welcome !!”);
Now, run the node welcome.js on command line/terminal (command
line/terminal should navigate that folder which contains welcome.js file).
You will see “welcome!!” on console.
Wow, you made one application in node.js. Now we will move to advance
version of node.js, where we will make http server and we will see this
text(“welcome!!”) in browser.

4. HTTP Server Web Application
var http = require("http");
http.createServer(function (req, res) {
console.log(“Your application is running on localhost:9000”);
req.on("end", function () {
res.writeHead(200, { 'Content­Type': 'text/plain' });
res.end(‘Welcome!!');
}).listen(9000);
Now, run the node welcome.js on command line/terminal
(command line/terminal should navigate that folder which contains
welcome.js file). This time, you will see in console “Your application
is running on localhost:9000”. When you will open your browser on
localhost:9000, you will see “welcome!!” on your screen.

5. var http = require("http");
First, we included http module as dependency.
http.createServer();
This function will create the server. Function passed two parameters.
req variable holds all request parameter.
res variable holds all response send to server.
res.writeHead(200, { 'Content­Type': 'text/plain' });
writeHead function is used to write headers to the response.
200 is HTTP status code (this one means success)
Second parameter holds header fields in object.
Here, we are sending plain text, so Content­Type should be text/plain.
We created our server and now will make it to listen at port 9000 like this:
listen(9000);

6. This is just start to Node.js Application, We will get back to you
soon with more interesting slides.
Thank You