PHP - Detect the incoming url requesting php page from another source/url

Question

Is there a way in which I can detect the URL that is calling in my php page, similar to say a GET or POST but would like to get the URL as I would like to restrict the page accessing it to a certain URL as this file is being called from another server.

Basically: www.MYURL.com calls the php file from say www.PHPURL.com if the URL is NOT www.MYURL.com then bounce them out etc.

Many Thanks

In response to the answers below I used the as mentioend and here is what I did:

  $URL_REF = parse_url($_SERVER['HTTP_REFERER']);
  $URL_REF_HOST =   $URL_REF['host'];

Thanks @Philip Bevan,@Itai Sagi and @EvilP

Answer 1

well, you could use $_SERVER['HTTP_REFERER'] - but it can be cloaked/removed.

EDIT: as someone asked, the HTTP_REFERER is a header which is sent by the client, most browsers default behavior is to send it, but if you'd like, you can disable it or even send a different referer header so people will think you come from some place else.

the bottom line: if it isn't THAT critical for you, you can use it, but don't EVER, EVER give people extra privileges based on their referer alone.

Answer 2

$_SERVER["HTTP_REFERER"]

is what you are looking for.