I have a library of classes, all interrelated.

Some files are inside the document root and some are outside using the <Directory> and Alias features in httpd.conf

Assuming I have 3 files:

webroot.php (Inside the document root)
alias_directory.php (Inside a folder outside the doc root)
alias_directory2.php (Inside a **different** folder outside the doc root)

If alias_directory2.php needs both webroot.php and alias_directory.php, This does not work. (Remember alias_directory.php and alias_directory2.php are not in the same locations)

require_once $_SERVER['DOCUMENT_ROOT'].'/webroot.php'; //(ok)
require_once $_SERVER['DOCUMENT_ROOT'].'/alias_directory.php'; //(not ok)

This does not work because alias_directory.php is not in the doc root.

Similarly

require_once $_SERVER['DOCUMENT_ROOT'].'/webroot.php'; //(ok)
require_once dirname(__FILE__).'/alias_directory.php'; //(not ok)

The problem here is that dirname(__FILE__) will return the path for alias_directory2.php not alias_directory.php.

This works:

require_once $_SERVER['DOCUMENT_ROOT'].'/webroot.php'; //(ok)
require_once '/full/path/to/directory/alias_directory.php'; //(ok)

But is very nasty and is a maintenance nightmare if I decide to move my library to another location.

How do I solve this problem, is seems that I need a way to resolve an Alias folder properly.