ExpressJS Server - How to handle multiple domains

Question

I'm fooling around a little with Express and I'm wondering, what the "most correct" way is to handle multiple domains which are linked to the same server.

Lets assume we have

foo.com
bar.net
baz.com

which all point to 111.222.333.444. That machine is running NodeJS with Express. My current solution looks like this:

var express = require( 'express' ),
    app     = module.exports = express.createServer(),
// ... more lines ...
app.get( '/', routes.index.bind( app ) );

Thus far this is pretty straightforward. The only exception so far is in my app.configure call, where I didn't make a call to .use( express.static() ). Thats because the .routes.index() method looks like so right now:

var fs    = require( 'fs' ),
// ... more lines ...

exports.index = function( req, res ) {
    var host = /(\w+\.)?(.*)\.\w+/.exec( req.header( 'host' ) ),
        app  = this;

    switch( host[ 2 ] ) {
        case 'foo':
            app.use( express.static( '/var/www/foo' ) );
            fs.readFile( '/var/www/foo/index.html', 'utf8', fileReadFoo );
            break;
        case 'bar':
            app.use( express.static( '/var/www/bar' ) );
            fs.readFile( '/var/www/bar/index.html', 'utf8', fileReadBar );
            break;
        case 'baz':
            // ... lines ...
            res.render( 'index', { title: 'Baz Title example' } );
            break;
        default:
            res.send('Sorry, I do not know how to handle that domain.');
    }

    function fileReadFoo( err, text ) {
        res.send( text );
    }

    function fileReadBar( err, text ) {
        res.send( text );
    }
};

What happens here is, that I analyse the req.header for the host entry and parse the domain name. Based on that, I call the .static() method so Express can serve the right static resources etc., furthermore, I just simply read and send the contents of the index.html files. I tried to use Jade aswell for serving plain HTML files, but the include directive in Jade only accepts relative pathes.

However, this indeed works, but I'm pretty unsure if that is a good practice.

Any advice / help welcome.

Update

I think I need to make this more clear. I'm not a beginner by any means. I'm very aware how ES works and other servers like NGINX. I'm looking for qualified answers on what the right thing with NodeJS/Express is. If it doesn't make any sense to use Node/Express for that, please elaborate. If there is a better way to do this with Node/Express, please explain.

Thanks :-)

user_2633817 · Answer

I would not recommend using Express in the first place. In fact, even for a single domain, using Node's http module, one can easily write an app with all the functionality that you get with Express.

For multiple domains, once you get the hostname, you can customize your routes or middleware or whatever you want to call them. As long as you do not have any blocking calls in any of the app, the number of domains your singe node process is going to serve is irrelevant. If CPU usage becomes a bottleneck, you can use cluster of the same process.

Clustering is not possible if you have in-memory session data. You will need another process to maintain state of which instance is managing that particular session. ALl this depends on how you are managing states, persistence of states, etc.

Overall, the answer is not simple unless other details are provided. I am providing a separate answer, rather than a comment because I BELIEVE THAT TOO MANY DEVELOPERS USE EXPRESS AND THEREBY LIMIT THEIR FLEXIBILITY.

ExpressJS Server - How to handle multiple domains

7 Answers