Question

我正在使用PHP脚本来控制对下载文件的访问。这适用于2Gb以下的任何内容，但对于较大的文件则无效。

Apache和PHP均为64位
Apache 将允许直接访问文件（我不能允许）

PHP的内核（忽略访问控制）：

if (ob_get_level())  ob_end_clean();

error_log('FILETEST: '.$path.' : '.filesize($path));
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename='.basename($path));
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($path));
readfile($path);
exit;

错误日志显示文件大小正确

[Tue Apr 08 11:01:16 2014] [error] [client *.*.*.*] FILETEST: /downloads/file.name : 2251373807, referer: http://myurl/files/

但访问日志的大小为负：

 *.*.*.* - - [08/Apr/2014:11:01:16 +0100] "GET /files/file.name HTTP/1.1" 200 -2043593489 "http://myurl/files/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0"

因此浏览器拒绝下载该文件。事实上，使用wget，它不会发送任何内容：

$ wget -S -O - http://myurl/files/file.name
--2014-04-08 11:33:38--  http://myurl/files/file.name
HTTP request sent, awaiting response... No data received.
Retrying.

Answer 1

尝试以块的形式读取文件并将它们暴露给浏览器，而不是用2GB填充本地内存并立即刷新所有文件。

将readfile($path);替换为：

@ob_end_flush();
flush();

$fileDescriptor = fopen($file, 'rb');

while ($chunk = fread($fileDescriptor, 8192)) {
    echo $chunk;
    @ob_end_flush();
    flush();
}

fclose($fileDescriptor);
exit;

在某些情况下，8192字节是关键点，引用php.net/fread。

添加一些microtime变量（并与文件描述符的指针位置进行比较）也可以控制下载的最大速度。

* （刷新输出缓冲区也略微取决于网络服务器，使用这些命令确保它至少尝试尽可能地刷新。）

Answer 2

之前我遇到过这个问题并使用下面的脚本来下载文件，它将文件分成大块以下载大文件，而不是一次性尝试获取整个文件。该脚本还考虑了所使用的浏览器，因为某些浏览器（即IE）可以稍微不同地处理标题。

private function outputFile($file, $name, $mime_type='') {
    $fileChunkSize = 1024*30;

    if(!is_readable($file)) die('File not found or inaccessible!');

    $size = filesize($file);
    $name = rawurldecode($name);

    $known_mime_types=array(
        "pdf" => "application/pdf",
        "txt" => "text/plain",
        "html" => "text/html",
        "htm" => "text/html",
        "exe" => "application/octet-stream",
        "zip" => "application/zip",
        "doc" => "application/msword",
        "xls" => "application/vnd.ms-excel",
        "ppt" => "application/vnd.ms-powerpoint",
        "gif" => "image/gif",
        "png" => "image/png",
        "jpeg"=> "image/jpg",
        "jpg" =>  "image/jpg",
        "php" => "text/plain"
     );

     if($mime_type=='')
     {
         $file_extension = strtolower(substr(strrchr($file,"."),1));
         if(array_key_exists($file_extension, $known_mime_types))
            $mime_type=$known_mime_types[$file_extension];
         else
            $mime_type="application/force-download";
     }

     @ob_end_clean();

     if(ini_get('zlib.output_compression'))
      ini_set('zlib.output_compression', 'Off');

     header('Content-Type: ' . $mime_type);
     header('Content-Disposition: attachment; filename="'.$name.'"');
     header("Content-Transfer-Encoding: binary");
     header('Accept-Ranges: bytes');
     header("Cache-control: private");
     header('Pragma: private');
     header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

     if(isset($_SERVER['HTTP_RANGE']))
     {
        list($a, $range) = explode("=",$_SERVER['HTTP_RANGE'],2);
        list($range) = explode(",",$range,2);
        list($range, $range_end) = explode("-", $range);
        $range=intval($range);
        if(!$range_end)
            $range_end=$size-1;
        else
            $range_end=intval($range_end);

        $new_length = $range_end-$range+1;
        header("HTTP/1.1 206 Partial Content");
        header("Content-Length: $new_length");
        header("Content-Range: bytes $range-$range_end/$size");
     } 
     else 
     {
        $new_length=$size;
        header("Content-Length: ".$size);
     }

     $chunksize = 1*($fileChunkSize);
     $bytes_send = 0;
     if ($file = fopen($file, 'r'))
     {
        if(isset($_SERVER['HTTP_RANGE']))
        fseek($file, $range);

        while(!feof($file) && 
            (!connection_aborted()) && 
            ($bytes_send<$new_length)
        )
        {
            $buffer = fread($file, $chunksize);
            print($buffer);
            flush();
            $bytes_send += strlen($buffer);
        }
     fclose($file);
     } 
     else die('Error - can not open file.');

    die();
}

Answer 3

在readfile（$ path）之前添加代码;

ob_clean();
flush();

我使用此代码进行下载：

if (file_exists($file)) {


        header('Content-Description: File Transfer');
        header('Content-Type: application/octet-stream');
        header('Content-Disposition: attachment; filename='.basename($file));
        header('Content-Transfer-Encoding: binary');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Pragma: public');
        header('Content-Length: ' . filesize($file));

        ob_clean();
        flush();
        readfile($file);
        exit;

    }

Answer 4

您最好的选择是使用这样的函数强制apache到http chunked模式。你会以这种方式节省大量的PHP内存。

function readfile_chunked($filename, $retbytes = TRUE) {
  $CHUNK_SIZE=1024*1024;
  $buffer = '';
  $cnt =0;
  $handle = fopen($filename, 'rb');
  if ($handle === false) {
    return false;
  }
  while (!feof($handle)) {
    $buffer = fread($handle, $CHUNK_SIZE);
    echo $buffer;
    @ob_flush();
    flush();
    if ($retbytes) {
      $cnt += strlen($buffer);
    }
  }
  $status = fclose($handle);
  if ($retbytes && $status) {
    return $cnt; // return num. bytes delivered like readfile() does.
  }
  return $status;
}

Apache / PHP大文件下载（＆gt; 2Gb）失败

4 个答案: