php简单防盗链实现方法

<?php$ADMIN = array(  'defaulturl'=> 'http://blog.qita.in/images/banner-header.gif',  //盗链返回的地址  'url_1'   => 'http://blog.qita.in/file',  'url_2'   => 'http://blog.qita.in/file1',);$okaysites = array( 'http://qita.in',  'http://blog.qita.in', //白名单  'http://blog.qita.in/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[defaulturl]");  }} else {  header("Location: $ADMIN[defaulturl]");}print_r($_SERVER['HTTP_REFERER']);?>