[Edit: Added wildcard DNS section at the end, also link to dnsmasq setup instructions; also quick info on nginx defaults]

After my Debugging Drupal talk at Copenhagen today a lot of people wanted to know how to use a wildcard virtualhost, so I promised a quick writeup.

The purpose here is to be able to deploy new virtualhost-style Drupal sites on your localhost without doing any apache configuration (or /etc/hosts, if you deploy a nameserver).

Most of the time Drupal works better (and more like your production site) if you run it as a production site. If I have a site like debugging_example.com, I run it locally as debugging_example.l. That's way better than localhost/debugging_example, because all the URLs work right, and it's clean URLs.

The basic idea of what you have to do:

• Enable mod_vhost_alias in Apache
• Configure a catchall virtualhost
• Tweak your .htaccess by uncommenting one line
• Make an entry in your /etc/hosts

Here's the quick version of how to do it:

1. Enable the mod_vhost_alias Apache module with sudo a2enmod vhost_alias (on Debian/Ubuntu, or however on your environment).
2. /etc/init.d/apache2 restart
3. Configure your httpd.conf or apache2.conf or whatever to provide a catchall. I use Debian/Ubuntu, and this is done with:
   • Create the file /etc/apache2/sites-available/catchall. Here is my catchall. You'll note you have to change the base path.
   • a2ensite catchall
   • /etc/init.d/apache2/reload
4. Make an entry in your hosts file for the virtualhost you want to use.
5. In your drupal .htaccess, uncomment the line that says
   # RewriteBase /
   so it says instead:
   RewriteBase /

And if you are ambitious and don't like adding each entry to /etc/hosts, here's a crude recipe for running bind9 (debian/ubuntu) to automatically resolve anything. I use *.l:

• /etc/bind/named.conf.local, add
  
  zone "l" {
        type master;
        file "/etc/bind/db.l";
        notify no;
};
• Add the file /etc/bind/db.l, adjusted for your use:
  
  $ttl 38400
@ IN SOA l.l. admin.l. (
2009091700
10800
3600
604800
38400 )
l. IN NS localhost.
*.l. IN CNAME localhost
• Change your computer to use localhost to resolve names. You can do this in the network config applet.

Update 2011-05-03: You might be interested in this article which shows how to do the same thing using dnsmasq, a lighter-weight DNS server.

Update 2011-05-03: To do the same thing in nginx as we did with Apache, this rule in /etc/nginx/sites-available/default will make nginx recognize any hostname like xxx.l or xxx.b or xxx.bigsony or www.xxx.b and send it to the /home/rfay/workspace/xxx directory.