UPDATE 2011-09-20

I made a connect module specifically for this purpose:

• Available on github: https://github.com/coolaj86/connect-vhoster
• See the bottom section of: http://coolaj86.info/articles/how-i-setup-my-vpses.html

[deprecated]

The rest of this article is left for archival and educational purposes.

Goal

Show 3 applications running on the same host.

todo

• get an app beyond-the basics

Pre-reqs:

• node v0.2.0
• npm
• connect

Procedure

Create some virtual hostnames:

/etc/hosts

127.0.0.1 localhost
127.0.0.1 hello
127.0.0.1 bye

or if your development box is public and online, it may have an IP such as

74.125.19.147 remotehost
74.125.19.147 hello
74.125.19.147 bye

or if you setup DNS for breakfast and take it back down for lunch just do your own thing...

Install connect:

npm install connect

Grab the test application:

Note that the names of the vhosts and the port numbers are arbitrary.

It is important that the vhost names should match the /etc/hosts names

~/node-vhost/vhosts.js:

/**
 * Module dependencies.
 */

var connect = require('connect'),
  host, hello, bye;

host = connect.vhost('peru', connect.createServer(function(req, res){
    res.writeHead(200, {});
    res.end('local (vhost)');
}));

hello = connect.vhost('hello', connect.createServer(function(req, res){
    res.writeHead(200, {});
    res.end('Hello World (vhost)');
}));

bye = connect.vhost('bye', connect.createServer(function(req, res){
    res.writeHead(200, {});
    // This will be caught and handled by connect,
    // which means doesn't cause the other servers to crash!
    throw Error('Goodbye World!!! AGH!!!!!');
    res.end('Goodbye World (vhost)');
}));

connect.createServer(
    // Shared middleware
    connect.logger(),
    host,   // http://host:7886 server with own middleware
    hello,  // http://hello:7886 server with own middleware
    bye     // http://bye:7886 server with own middleware
).listen(7886);

Run the app:

cd ~/node-vhost/
node vhosts.js

Visit it in your browser:

http://hello:7886
http://bye:7886

Adding Applications as Applications

~/node-apps/hello.js:

var connect = require('connect');

exports.hello = function(req, res){
    res.writeHead(200, {});
    res.end('Hello World (vhost)');
};

~/node-apps/bye.js:

var connect = require('connect');

exports.bye = function(req, res){
    res.writeHead(200, {});
    // This will be caught and handled by connect,
    // which means doesn't cause the other servers to crash!
    throw Error('Goodbye World!!! AGH!!!!!');
    res.end('Goodbye World (vhost)');
} 

~/node-vhost/vhosts.js:

var connect = require('connect'),
  hello_app = require('../node-apps/hello').hello,
  bye_app = require('../node-apps/bye').bye,
  host, hello, bye;

host = connect.vhost('peru', connect.createServer(function(req, res){
    res.writeHead(200, {});
    res.end('local (vhost)');
}));

hello = connect.vhost('hello', connect.createServer(hello_app));
bye = connect.vhost('bye', connect.createServer(bye_app));

connect.createServer(
    // Shared middleware
    connect.logger(),
    host,   // http://host:7886 server with own middleware
    hello,  // http://hello:7886 server with own middleware
    bye     // http://bye:7886 server with own middleware
).listen(7886);

Run it again:

cd ~/
node node-vhosts/vhosts.js

You should get the same results. The upshot to this is that you're running multiple applications in one process. The downshot to this is that you have to restart all applications to add a new one.

Remember, this app is just like a browser app. It's not like a Rails, Django, Pylons, or PHP app. Everything is still event driven just like in the browser.

An http request to this server is roughly equivalent to a button click in the browser. Both stateless. Both event-driven.

By AJ ONeal


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