在PHP中强制下载图像。 在本地工作但在实时Linux服务器上中断

Question

I am forcing the download of an image through my website.

Forced download works fine on Apache/Windows development machine.

However it pushes junk characters to the screen when live on my linux web server.

e.g. �����JFIF��H�H����6Exif��MM�*����

• Firefox - junk
• Chrome - junk

• Internet Explorer 7 - displays the image in the page

  $fileName = basename($filePath);
  $fileSize = filesize($filePath);
  
  
  // Output headers.
  header("Cache-Control: private");
  header("Content-Type: Image/jpeg");
  header("Content-Length: ".$fileSize);
  header("Content-Disposition: attachment; filename=".$fileName);
  
  
  // Output file.
  readfile ($filePath);                   
  exit();
  

What differences might there be on my live server that would cause it to break?

Answer 1

Hat tip (and +1) to stillstanding, who pointed out using fifo, but I thought I'd provide an example here to help. This example requires the fifo extension installed, and has been hacked out and slightly modified from some other code of mine.

    $filename = 'blarg.jpg';
    $filepath = '/foo/bar/blarg.jpg';
    $finfo    = new finfo(FILEINFO_MIME);
    $mime     = $finfo->file($file);

    // Provide a default type in case all else fails
    $mime = ($mime) ? $mime : 'application/octet-stream';

    header('Pragma: public');
    header('Content-Transfer-Encoding: binary');
    header('Content-type: ' . $mime);
    header('Content-Length: ' . filesize($filepath));
    header('Content-Disposition: attachment; filename="' . $filename . '"');

    header('Content-transfer-encoding: 8bit');
    header('Expires: 0');
    header('Pragma: cache');
    header('Cache-Control: private');