Entry

Can I access Environment Variables from inside PHP scripts?

What Environment Variables are available to my PHP script?

What HTTP_ variables are available in PHP?

Jul 8th, 2002 22:10
Philip Olson, Nathan Wallace,

The PHP manual lists many of these predefined variables here:

  http://www.php.net/manual/en/language.variables.predefined.php

There are a few ways to access these predefined variables.  Here are
some examples using HTTP_REFERER:

  <?php

    // works as of PHP 3
    print $HTTP_SERVER_VARS['HTTP_REFERER'];

    // works as of PHP 4.1.0
    print $_SERVER['HTTP_REFERER'];

    // works if the php directive register_globals = on.
    // as of PHP 4.2.0 this directive defaults to off.
    print $HTTP_REFERER;

  ?>

For a complete list of environment variables available to your scripts, 
use phpinfo{} to see "what's available", you should do this as server 
setups allow for different environment variables.  Use phpinfo as such:

  <?php phpinfo() ?>

Another way to access these variables is by use getenv():

  http://www.php.net/manual/en/function.getenv.php

On a related note, you can read about register_globals here:

  http://www.php.net/manual/en/configuration.php#ini.register-globals