如何允许来自多个站点的http referer

Question

I would like to know how to allow http refer from more than 1 site.

For example

<?php
$domain='example.net';
$referrer = $_SERVER['HTTP_REFERER'];
if (@preg_match("/example.net/",$referrer)) {
} else {
header('Location: http://www.example.net/404.php');
};
?>

This code works if I open links from example.net, but I want to allow example1.net and example2.net as well to access the links.

How do I do this? If anyone could help me with this, it would highly be appreciated.

Answer 1

Use the regex operator for or -- | (pipe)

<?php
$domains = Array(
    'example.net',      
    'example2.net'
);
$referrer = parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST); // Gets the domain name from referer
if (!preg_match("/" . implode('|', $domains) . "/", $referrer)) {
    header('Location: http://www.example.net/404.php');
    exit(0); //force exit script after header redirect to ensure no further code is executed.
};

// Normal code execution here...
?>