Prevent direct access to a php include file

Question

I have a php file which I will be using as exclusively as an include. Therefore I would like to throw an error instead of executing it when it\'s accessed directly by typing

Answer 1

I wanted to restrict access to the PHP file directly, but also be able to call it via jQuery $.ajax (XMLHttpRequest). Here is what worked for me.

if (empty($_SERVER["HTTP_X_REQUESTED_WITH"]) && $_SERVER["HTTP_X_REQUESTED_WITH"] != "XMLHttpRequest") {
    if (realpath($_SERVER["SCRIPT_FILENAME"]) == __FILE__) { // direct access denied
        header("Location: /403");
        exit;
    }
}