At any given time, there are about a dozen or so websites that I help develop in some form or another. The easiest way to work on a site is to maintain a copy of it on my local machine… nothing special there. However, what if you want to view the development version of the site? Just fire it up in your web browser. What if you use server side scripting like PHP that needs to be run? OS X has a built-in webserver making this fairly simple by placing the files in your ~/Sites/ folder. But what if your site contains links that are relative to the site root such as <img src="/images/logo.jpg" />? Because you would be accessing this site as http://localhost/~username/test_site/, your image will fail do load. You could setup VirtualHosts for each of your development sites, and in fact I did this for a long time. The problem is that this can become a big annoyance and is an awful lot of work, especially if you have a large number of sites in development.

Apache’s VirtualDocumentRoot directive allows you to dynamically set the document root based on the host name that was used to request the document. So what we want to do is to create a unique host name for each website that we’re working on, and have apache find the appropriate document root for that particular site. We’ll start with just one development site - example.com. First we need a place to store the files for this site.. how about ~/Sites/example/public_html/. I put everything in a ‘public_html’ folder because I will often intentionally store some files outside of the document root, such as configuration files that contain passwords and such (for that I would use ~/Sites/example/include/ which I would also then add to my php include_path).

Next we need a unique host name that we can use to access our site. Apache will use parts of the hostname to determine what folder to use, so the easiest thing is to just make them the same… so we will use “example”. (An important thing to note here is that you can’t use a real domain name to access the development site. You could however create your own top level domain to use such as “example.dev”, but it’s certainly not necessary.) Once you’ve decided on a host name, you need to tell your computer that this name should resolve to the local machine. Do this by adding an entry to your /etc/hosts file along the lines of

127.0.0.1   example

If you have more than one development site, they can all be on one line seperated by spaces…

127.0.0.1   example1 example2 example3

Finally, you need to tell Apache to use virtual document roots. Based on the example setup we are using, you’ll want to add the following line to your apache configuration file (/etc/httpd/httpd.conf)

VirtualDocumentRoot /Users/username/Sites/%0/public_html/

In OS X, the virtual host module is not on by default so you will need to uncomment the following lines

# Around Line 205
LoadModule vhost_alias_module libexec/httpd/mod_vhost_alias.so
...
# Around Line 248
AddModule mod_vhost_alias.c

Additionally, you will need to turn off canonical names

# Around Line 503
UseCanonicalNames   Off

Then just restart apache and you should be on your way. For each additional site now, you just need to create a folder in ~/Sites/ and add an appropriate entry to /etc/hosts.

Notes:

• the DOCUMENT_ROOT that your scripts see will still be whatever one is explicitly defined in your Apache config file (something like /Library/WebServer/Documents/), so you may run into problems if your scripts rely on this variable. There is no way that I know of to get around this.

• it is not possible to have separate cgi-bin directories for each site that I am aware of. They will all use the system default one (/Library/WebServer/CGI-Executables/).

  To allow for per-site CGI bins, comment out the ScriptAlias directive in the main apache config file

    # Around Line 672
    ScriptAlias /cgi-bin/ "/Library/WebServer/CGI-Executables/"
  

  and create an .htaccess file in each site’s cgi-bin with the following:

    Options +ExecCGI
    SetHandler cgi-script
  

• reading of .htaccess files seems to be inconsistent. I thought I had them working at one time, but they don’t seem to be right now.

  By default, OS X sets AllowOverride None for user sites, so that .htaccess files are ignored – update this in /etc/httpd/users/[username].conf (not in the main apache config file as one might expect).

• these sites will not be accessible from any other machine unless they know to setup those host names to resolve to your computer’s IP address. This may or may not be what you want – it prevents someone from stumbling upon your development site (security by obscurity), but it makes it slightly more difficult to intentionally show a site to someone else.

• if you still want to run a “main” website for your computer, you can create a virtual host with the name of your machine. For example, if your machine were named “aquinas” and people would normally get to your machine’s website by going to http://aquinas.local/, then you just need to create your site in ~/Sites/aquinas.local/public_html/. You could even just make this a symlinked directory back to /Library/WebServer/Documents/ if you wish for your “main” site to reside there.

• all of the examples here are referring to file locations and configurations that come on a stock OS X Tiger box. Nothing about this is specific to OS X, so just apply the same principles to whatever OS you have apache running on.