How to check referral url and re-direct based on that?

I need to check referral url and if it's generated from Faceboo开发者_运维知识库k redirect the user to a different webpage. How do I do that?

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Take a look in $_SERVER['HTTP_REFERER'].

You can then use parse_url() to get the hostname, and compare the domain to a list of known Facebook domains.

Beware, the referer isn't required, and isn't always set. So, don't use it as any kind of security.

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if (stripos(parse_url($_SERVER['HTTP_REFERER'], PHP_URL_HOST), 'facebook') !== FALSE) {
   header('Location: differentwebpage.html');
}