PHP anti-leeching code _ php instance

The PHP anti-leeching code modified by a friend can be shared here to make it easier for a friend who needs it The code is as follows:

/**
* @ Author seraphim
* @ Copyright 2012
*/
$ ADMIN = array (
'Defaulturl '=> 'http: // www.xx.com/images/banner-header.gif', // address returned by leeching
'URL _ 1' => 'http: // www.xx.net/file ',
'URL _ 2' => 'http: // www.xx.net/file1 ',
);
$ Okaysites = array (
'Http: // box.baidu.com ',
'Http: // tieba.baidu.com/p/1493336008', // whitelist
'Http: // www.xx.com/1.html ',
);
$ Reffer = $ _ SERVER ['http _ referer'];
If ($ reffer ){
$ Yes = 0;
While (list ($ domain, $ subarray) = each ($ okaysites )){
If (ereg ($ subarray, "$ reffer ")){
$ Yes = 1;
}
}
$ Theu = 'URL _ '. $ _ GET ['site'];
$ File = $ _ GET ['file'];
If ($ ADMIN [$ theu] and $ yes = 1 ){
Header ("Location: $ ADMIN [$ theu]/$ file ");
} Else {
Header ("Location: $ ADMIN [defaurl URL]");
}
} Else {
Header ("Location: $ ADMIN [defaurl URL]");
}
Print_r ($ _ SERVER ['http _ referer']);
?>