如何在PHP中下载大文件

Question

I use this code to download/read files from a server.

  header("Expires: 0");
  header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
  header("Cache-Control: no-store, no-cache, must-revalidate");
  header("Cache-Control: post-check=0, pre-check=0", false);
  header("Pragma: no-cache");  
  header("Content-type: application/file");
  header('Content-length: '.filesize($file_to_download));
  header('Content-disposition: attachment; filename='.basename($file_to_download));
readfile($file_to_download);
   exit;

it's working fine to download files but when the file is big it's showing an error "File not found, problem file loading". Please tell me what I could change on this code for big file downloads.

Answer 1

Try like this:

$chunkSize = 1024 * 1024;
$fd = fopen($file_to_download, 'rb');

while (!feof($fd)) {   
    $buffer = fread($fd, $chunkSize);
    echo $buffer;
    ob_flush();
    flush();
}

fclose($fd);