Free Surf 34

PHP $_SERVER variables comparison


$_SERVER is a PHP array which contains information collected by the web server, frequently vital for your PHP script, like headers, paths or script locations.

$_SERVER['REQUEST_URI'], $_SERVER['PHP_SELF'] and $_SERVER['SCRIPT_NAME'] are homogenous PHP server variables ($_SERVER).

In many cases $_SERVER['REQUEST_URI'] will contain the same value with $_SERVER['PHP_SELF'] and $_SERVER['SCRIPT_NAME'], but sometimes they may differ. However, in all the cases the information is about the currently executing php script.

The goal of this PHP tutorial is to identify the different practical behaviors of these three important PHP variables.

According to PHP help, 'PHP_SELF' returns the filename of the currently executing script, relative to the document root. Let's take some practical examples:

http://www.sample-website.com/php-server-variables/ >>> / php-server-variables/index.php
http://www.sample-website.com/php-server-variables/script.php >>> / php-server-variables/script.php
http://www.sample-website.com/php-server-variables/script.php?var=help >>> /php-server-variables/script.php
http://www.sample-website.com/php-server-variables/script.php/my-php-tutorial >>> /my-php-tutorial

In the first three examples $_SERVER['PHP_SELF'] variable returned the filename of the currently executing script relative to the document root without taking into account the arguments variables. However, in the fourth php example it behaved differently.


The PHP help says that 'REQUEST_URI' gives you the URI which was entered in order to access the page:

http://www.sample-website.com/variables/ >>> /
http://www.sample-website.com/variables/script.php >>> /variables/index.php
http://www.sample-website.com/variables/script.php?var=help >>> /variables/script.php?var=help
http://www.sample-website.com/variables/script.php/my-php-tutorial >>> /variables/script.php/ my-php-tutorial

In all the cases, $_SERVER['REQUEST_URI'] returns exactly what is entered in the browser URL. This can be very useful to retrieve the exact URL, for example when using modrewrite (mod rewrite).

In PHP help, 'SCRIPT_NAME' variable is described as containing the current script's path:

http://www.sample-website.com/server-variables/ >>> /server-variables/index.php
http://www.sample-website.com/server-variables/index.php >>> /server-variables/index.php
http://www.sample-website.com/server-variables/index.php?var=help >>> /server-variables/index.php
http://www.sample-website.com/server-variables/index.php/my-php-tutorial >>> /server-variables/index.php

As we can see, $_SERVER['SCRIPT_NAME'] always returns php script name and only the php script name. This is useful for php pages which need to point to themselves.

More PHP tutorials in the next SoftSpecialist articles. Until next time Keep Safe! Safe websites and safe php scripts.