php下载远程大文件（获取远程文件大小）

今天跟大家分享一段获取远程文件大小以及下载远程大文件的PHP代码：

<?php
  // 暂不支持断点续传
  // $url = \'http://www.mytest.com/debian.iso\'; 不知道为何获取本地文件大小为0
  $url = \'http://192.168.8.93/download/vm-672/18/0.vmdk\';
  $file = basename($url);
  $header = get_headers($url, 1);
  $size = $header[\'Content-Length\'];
  $fp = fopen($url, \'rb\');
  if ($fp === false) exit(\'文件不存在或打开失败\');
  header(\'Content-Description: File Transfer\');
  header(\'Content-Type: application/octet-stream\');
  header(\'Content-Disposition: attachment; filename="\'.$file.\'"\');
  header(\'Content-Transfer-Encoding: binary\');
  header(\'Expires: 0\');
  header(\'Cache-Control: must-revalidate, post-check=0, pre-check=0\');
  header(\'Pragma: public\');
  header(\'Content-Length: \' . $size);
  ob_clean();
  ob_end_flush();
  set_time_limit(0);
  
  $chunkSize = 1024 * 1024;
  while (!feof($fp)) {
  $buffer = fread($fp, $chunkSize);
  echo $buffer;
  ob_flush();
  flush();
  }
  fclose($fp);
  exit;