• Hello World at Command Prompt
• Hello World HTTP Server
• Counter
• Hello World Module
• Parse Log File
• Using Forever
• Forever commands
• Nginx Server Block
• Express Framework
• NPM

Learning Node.JS Programming

• http://jothut.com/cgi-bin/junco.pl/tag/nodejs
• http://jothut.com/cgi-bin/junco.pl/b/17499/NodeJS-for-newbies
• http://nodejs.org
• https://www.npmjs.org
• http://nodejs.org/docs/v0.4.11/api/http.html#http.request
• http://package.json.nodejitsu.com
• http://inessential.com/2013/12/09/getting_started_with_node_js_for_cocoa_
• http://inessential.com/2013/12/09/getting_started_with_web_services_using_
• http://expressjs.com/4x/api.html
• http://howtonode.org/hello-node
• http://www.2ality.com/2011/12/nodejs-shell-scripting.html
• http://www.theprojectspot.com/tutorial-post/Node-js-for-beginners-part-1-hello-world/2
• http://www.theprojectspot.com/tutorial-post/nodejs-for-beginners-callbacks/4
• http://nodeguide.com/beginner.html
  • http://eloquentjavascript.net
• http://blog.modulus.io/absolute-beginners-guide-to-nodejs

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

Using Forever

Running a Node.js app as daemon.

The purpose of Forever is to keep a child process (such as your node.js web server) running continuously and automatically restart it when it exits unexpectedly.

I made a change to my Ghost blog installation config file. I killed the Ghost index.js process. When I did, it automatically restarted and loaded the new config settings.

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

https://github.com/nodejitsu/forever

$ npm install forever

$ forever start /home/nodejs/counter.js

Forever commands

usage: forever [start | stop | stopall | list] [options] SCRIPT [script options]

options:
  start          start SCRIPT as a daemon
  stop           stop the daemon SCRIPT
  stopall        stop all running forever scripts
  list           list all running forever scripts

Nginx Server Block

$ cd /etc/nginx/sites-available

$ vim nodejs.yoursite.com

The server block file:

server {
    listen   80;
    server_name nodejs.yoursite.com;
    location / {
      proxy_pass  http://nodejs.yoursite.com:8080;
    }
}

$ service restart nginx

In browser, access: http://nodejs.yoursite.com

Each refresh will update the counter. Should see something like this:

Hello!
We have had 18 visits!

Express Framework

http://expressjs.com

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

npm install express

When you install a module, it will put it in a node_modules folder inside your application directory. You can now require it like any built-in module.

file: static-file-server.js

code:

var express = require('express'),
    app = express();
app.use(express.static(__dirname + '/public'));
app.listen(8081);

execute: node static-file-server.js

NPM

There are thousands of modules available that solve almost all typical problems that you're likely to encounter. Remember to check npm before re-inventing the wheel. It's not unheard of for a typical Node.js application to have dozens of dependencies. In the previous example we manually installed Express. If you have a lot of dependencies, that's not going to be a very good way to install them. That's why npm makes use of a package.json file. package.json

{
  "name" : "MyStaticServer",
  "version" : "0.0.1",
  "dependencies" : {
    "express" : "3.3.x"
  }
}

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