starting with node.js
TRANSCRIPT
Jitendra Zaa
What is Node.js Is Light Weight Server
Used to create scalable network based application using JavaScript like Syntax
Why Node.js Uses same JavaScript engine which is used by Google Chrome
Browser “V8 JavaScript Runtime”.
Mostly for very Low level network programming
Very fast because most of modules created in C language Single Threaded application
It is not web development framework and not a completereplacement of PHP or Ruby like language.
However, there are few modules available like “Express.js” tocreate Single page applications
What's Different about Node.js Most expensive job for processor is reading content
from Harddisc (IO Jobs).
Most programming languages wait for read/write tocomplete and then executes next statement.
Unlike others, node.js executes IO operationsasynchronously and callback method is used toresume an operation which needs to be completedafter IO.
First Program – Hello World// Load the http module to create an http server.var http = require('http');
// Configure our HTTP server to respond with Hello World to all requests.var server = http.createServer(function (request, response) {response.writeHead(200, {"Content-Type": "text/plain"});response.end("Hello World\n");
});
// Listen on port 8000, IP defaults to 127.0.0.1server.listen(8000);
// Put a friendly message on the terminalconsole.log("Server running at http://127.0.0.1:8000/");
Running First Program Save Code shown on previous slide in file named
“HelloWorld.js”
Open Command Prompt and run file with Node command
Running First Program (cont)
On Console, you would see message saying Server is running.
And we open address “http://localhost:8000/” in browser, Hello world will be displayed
Creating Web Application
ExpressJs - Install Node Modules Express (http://expressjs.com/) is mostly adapted web
module for Node.js to create Single page websites.
To Install ExpressJs Module, create “Package.json” in folder
“Package.json” has metadata informations for module needs to be installed
Package.json{
"name": "hello-world",
"description": "hello world test app",
"version": "0.0.1",
"private": true,
"dependencies": { "express": "3.x" }
}
Installing ExpressJs ModuleAfter creation of “Package.json”, run command
npm install
in folder where “package.json” exists.
Simplest Web Application in Node.js
var express = require('express');
var app = express(); // create our app w/ express
app.configure(function() {
app.use(express.logger('dev')); // log every request to the console
app.use(express.json()); // Do not use bodyParser() , Instead use json() and urlencoded()
app.use(express.urlencoded()); // bodyparser() is depreciated from Express 3.0
});
app.get('/2', function(req, res) {
res.sendfile(__dirname + '/Page2.html');
});
app.get('*', function(req, res) {
res.sendfile(__dirname + '/Test Arrow.html');
});
app.listen(8080); //Listen on Port
console.log("App listening on port 8080");
Creating Sample HTML Files Save code of previous slide, in file named
“ExpressDemo.js”
Html File 1 – “Test Arrow.html”
Html File 2 – “Page2.html”
Start Node application using command “node ExpressDemo.js”
Running Web application Initially on navigation at http://localhost:8080/ we will
see content of “Test Arrow.html” file.
If we change URL with something like http://localhost:8080/2 , node server will post content of file “Page2.html”
Output
Thanks !!!