node.js:: what does hostname do in `listen` function?

Question

I own two domains, abc.com and xyz.com (not the real ones I own, but they work as an example). They both point to the same ip address. The following is my server js file:

var sys=require('sys'),
  http=require('http'),
  settings=require('./settings');



var srv = http.createServer(function(req, res) {
    var body="<b>Hello World!</b>"
    res.writeHead(200, {
        'content-length': body.length,
          'content-type': 'text/html',
          'stream': 'keep-alive',
          'accept': '*/*'
          }
      );
    res.end(body);
  });

srv.listen(8000, 'abc.com' ); // (settings.port, settings.hostname);

I then visit http://abc.com:8000/ and http://xyz.com:8000/ and they both display the webpage. I thought that I would only be able to see the page on abc.com since that's what I set as the hostname.

However, when I put '127.0.0.1' as the hostname, then I can only view the page via wget on the server itself.

So what does the hostname parameter do?

Answer 1

The following segment of code inside net.js that defines the listen function is pertinent:

// the first argument is the port, the second an IP    
var port = arguments[0];
dns.lookup(arguments[1], function (err, ip, addressType) {
  if (err) {
    self.emit('error', err);
  } else {
    self.type = addressType == 4 ? 'tcp4' : 'tcp6';
    self.fd = socket(self.type);
    bind(self.fd, port, ip);
    self._doListen();
  }
});

So basically providing a url as the hostname parameter does not allow shared hosting. All node.js does is do the work for you of resolving a hostname to an ip address -- and since in my case both domains point to the same ip, both will work.

For me to do shared hosting, I must find another way.