What is the "No direct file load" code line purpose?

[welovewebdesign]

I'd never seen this line of code in a WordPress theme before. Is it a specific lesintegristes-theme's requirement?

if (!empty($_SERVER['SCRIPT_FILENAME']) && realpath($_SERVER['SCRIPT_FILENAME']) === realpath(__FILE__)) { die(); }

[bpierre]

It is for preventing direct access to the files. The web server should prevent direct access to the theme files (.htaccess), but this is an additionnal mesure.

// The PHP file called by the server
// (with WordPress, everything is managed by the index.php file)
echo $_SERVER['SCRIPT_FILENAME'];
// The current file
echo __FILE__;

// If both names are the same, it means the current file has been directly called.

Example: http://www.lesintegristes.net/wp-content/themes/lesintegristes/sidebar.php http://www.presse-citron.net/wordpress_prod/wp-content/themes/steaw-citron/sidebar.php

[bpierre]

We should replace it with:

if (!defined('WP_USE_THEMES')) return;

Since the WP_USE_THEMES constant is defined in the index.php file.