Setting up wildcard domains on local host (OS X 10.5)?

Question

I am starting to develop a site which basically acts as WordPress MU, in the sense that a user can signup and have their own blog. I will be coding this in Rails, however I am hoping to be able to utilize wildcard subdomains, so I can use the format such as blog.example.com. I've done some searching but I can't find any good resources.

Since I am using Rails, I'm not sure where to put this, as I am using Mongrel, and not Apache. I can bypass doing this on my local machine by developing remotely on my server, however I would only like to keep this as a last resort.

I can give more details about my development environment if needed, but here are the basics:

• Mac OS X Leopard 10.5.6
• Ruby 1.8.7
• Rails 2.3.2

Answer 1

Strictly speaking, it's not possible to do that in the hosts file (at least on OS X). It's possible to simulate the behavior with Firefox by configuring it to use a proxy autoconfigure script.

Create a file with the following javascript (I use ~/.proxy.pac)

function FindProxyForURL(url, host) {
  if (shExpMatch(host,"*.<YOUR_DOMAIN>")) {
    //alert("proxy local")
    return "PROXY localhost";
  }
//alert("proxy direct")
return "DIRECT";
}

Then in Firefox > Preferences > Advanced > Network > Settings... > Automatic Proxy Configuration URL:

file:///Users/USERNAME/.proxy.pac

Never tried it in Safari, but it supports PAC files also, so perhaps it works...

The only other alternative I know is to set up a full blown DNS server on your PC...