Get parent directory of running script


Question

In PHP, what would be the cleanest way to get the parent directory of the current running script relative to the www root? Assume I have:

$_SERVER['SCRIPT_NAME'] == '/relative/path/to/script/index.php'

Or just:

$something_else == '/relative/path/to/script/'

And I need to get /relative/path/to/ with slashes properly inserted. What would you suggest? A one liner is preferred.

EDIT

I need to get a path relative to the www root, dirname(__FILE__) gives me an absolute path in the filesystem so that won't work. $_SERVER['SCRIPT_NAME'] on the other hand 'starts' at the www root.

1
63
12/10/2009 4:15:17 PM

Accepted Answer

If your script is located in /var/www/dir/index.php then the following would return:

dirname(__FILE__); // /var/www/dir

or

dirname( dirname(__FILE__) ); // /var/www

Edit

This is a technique used in many frameworks to determine relative paths from the app_root.

File structure:

 /var/
      www/
          index.php
          subdir/
                 library.php

index.php is my dispatcher/boostrap file that all requests are routed to:

define(ROOT_PATH, dirname(__FILE__) ); // /var/www

library.php is some file located an extra directory down and I need to determine the path relative to the app root (/var/www/).

$path_current = dirname( __FILE__ ); // /var/www/subdir
$path_relative = str_replace(ROOT_PATH, '', $path_current); // /subdir

There's probably a better way to calculate the relative path then str_replace() but you get the idea.

126
12/10/2009 4:48:07 PM

As of PHP 5.3.0 you can use __DIR__ for this purpose.

The directory of the file. If used inside an include, the directory of the included file is returned. This is equivalent to dirname(__ FILE__).

See PHP Magic constants.

C:\www>php --version
PHP 5.5.6 (cli) (built: Nov 12 2013 11:33:44)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2013 Zend Technologies

C:\www>php -r "echo __DIR__;"
C:\www

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