我正在制作一个文件，用于下载存储在我的网站中的文件。但是，当我尝试单击按钮下载文件时，它不会加载文件。我正在使用header函数来做这件事。有人能回答我为什么在使用wp-load.php 还是我做错了什么。这是我的代码：

  <?php
  require_once(dirname(__FILE__) . \'/wp-load.php\');
  function lastlink($str){
  $regexp = "<a\\s[^>]*href=(\\"??)([^\\" >]*?)\\\\1[^>]*>(.*)<\\/a>";
  if(preg_match_all("/$regexp/siU", $str, $matches)) {
   $str= end($matches[2]);
  }
  return $str;
   }
 $url=$_POST[\'url\'];
 $id=url_to_postid($url);
 $content_post = get_post($id);
 $content = $content_post->post_content;
 $content = apply_filters(\'the_content\', $content);
 $content = str_replace(\']]>\', \']]&gt;\', $content);
 $ur=loadd(lastlink($content));
 $name = \'gameofthrones.mp4\';
 if(isset($_POST["downloadfile"])) {
 $url=str_replace(" ","%20",$ur);
 header(\'Expires: 0\'); // no cache
 header(\'Cache-Control: must-revalidate, post-check=0, pre-check=0\');
 header(\'Last-Modified: \' . gmdate(\'D, d M Y H:i:s\', time()) . \' GMT\');
 header(\'Cache-Control: private\', false);
 header(\'Content-Type: application/force-download\');
 header(\'Content-Disposition: attachment; filename="\' . $name . \'"\');
  header(\'Content-Transfer-Encoding: binary\');
 header(\'Content-Length: \' . get_remote_size($url)); // provide file size
 header(\'Connection: close\');
  readfile($url);
  }
 ?>
<form method="POST">
  <input type="submit" value="DOWNLOAD FILE" name="downloadfile"/>
</form>