You're viewing old version number 26. - Current version

2 min

Learning Node.JS Programming

Hello World at Command Prompt

Open up a text file and enter:

// Call the console.log function.
console.log("Hello World");

Save file as hello-console.js and then at the command prompt, execute:
node hello-console.js

Obviously, that produces:
Hello World

Hello World HTTP Server

Add the following code to a file called:
hello-server.js


// 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 8080, IP defaults to 127.0.0.1
server.listen(8080);

// Put a friendly message on the terminal
console.log("Server running at http://127.0.0.1:8080/");

Execute the code with:
node hello-server.js

The following message will be displayed to the console:
Server running at http://127.0.0.1:8080/

Point the browser to the domain/sub domain of the server with the port included. Example:
http://nodejs.soupmode.com:8080

If running the server and the browser on the same machine, use: http://localhost:8080

If the above server code is running, then the following will be displayed in the browser:
Hello World

To stop this server app, hit Ctrl-C at the command prompt.

Counter

Add the following code to counter.js


var http = require('http');

var userCount = 0;
http.createServer(function (request, response) {
    console.log('New connection');
    userCount++;

    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.write('Hello!\n');
    response.write('We have had '+userCount+' visits!\n');
    response.end();
}).listen(8080);

console.log('Server started');

Execute the code with:
node counter.js

The message displayed to the console will say:
Server started

When accessing the server at port 8080 in the browser, the following will be displayed to the browser:
Hello!
We have had 1 visits!

Back at the server, the console display will say:
New connection
New connection

A refresh on the browser will cause the following message to be sent by the counter.js app:
Hello!
We have had 3 visits!

The counter increments by two.

Explanation from the article :

Note: You might see the counter going up by two for each request, this is because your browser is requesting the favicon from the server (http://localhost:8080/favicon.ico).

You should also see that Node.js is logging each request it receives to the console.

The main thing we're doing here is setting a 'userCount' variable and incrementing on each request. We're then writing the 'userCount' in the response text.

Hello World Module

http://nodeguide.com/beginner.html

Create the file main.js with the following code:

var hello = require('./hello');
hello.world();

In the same directory, create another file called hello.js with the following code:

exports.world = function() {
  console.log('Hello World');
}

Execute at the command prompt:
node main.js

The console will display the following:
Hello World

Parse Log File

http://blog.modulus.io/absolute-beginners-guide-to-nodejs

Express Framework

http://blog.modulus.io/absolute-beginners-guide-to-nodejs

npm install express

file: static-file-server.js

code:

var express = require('express'),
    app = express();
app.use(express.static(__dirname + '/public'));
app.listen(8080);

execute: node static-file-server.js

Running Node.js App as Daemon

http://stackoverflow.com/questions/4018154/node-js-as-a-background-service

https://www.npmjs.org/package/forever

http://blog.nodejitsu.com/keep-a-nodejs-server-up-with-forever

$ npm install forever

$ forever start /home/nodejs/counter.js

Nginx Server Block

`/etc/nginx/s

#nodejs - #programming - #javascript - #howto

From JR's : articles
498 words - 4632 chars - 2 min read
created on
updated on - #
source - versions

Related articles
Learning Node.JS Programming - Nov 10, 2014
React Native - Nov 01, 2016
NodeJS for newbies - Nov 01, 2013
App idea to learn new code - Mar 10, 2014
Links feb 25, 2017 - Feb 25, 2017
more >>



A     A     A     A     A

© 2013-2017 JotHut - Online notebook

current date: Nov 15, 2024 - 4:43 p.m. EST