浏览器使用运行下载的 PHP 文件名下载文件

Question

我使用 PHP 将下载发送到浏览器。我在名为 download.php 的文件上运行代码。

问题：有时不是下载文件，而是下载相同的文件（相同大小），但名称为download.php。

我还注意到，当我尝试使用Internet Download Manager 下载它时，我看到名称download.php 大约半秒钟，然后名称变为真实名称。

图片说明：

代码：

//First, see if the file exists
if (!is_file($file)) {
    header("HTTP/1.1 400 Invalid Request");
    die("<h3>File Not Found</h3>");
}

//Gather relevent info about file
$size = filesize($file);
$fileinfo = pathinfo($file);

//workaround for IE filename bug with multiple periods / multiple dots in filename
//that adds square brackets to filename - eg. setup.abc.exe becomes setup[1].abc.exe
$filename = (isset($_SERVER['HTTP_USER_AGENT']) && strstr($_SERVER['HTTP_USER_AGENT'], 'MSIE')) ?
              preg_replace('/\./', '%2e', $fileinfo['basename'], substr_count($fileinfo['basename'], '.') - 1) :
              $fileinfo['basename'];

$file_extension = strtolower($fileinfo['extension']);

//This will set the Content-Type to the appropriate setting for the file
switch($file_extension)
{
    case 'exe': $ctype='application/octet-stream'; break;
    case 'zip': $ctype='application/zip'; break;
    case 'mp3': $ctype='audio/mpeg'; break;
    case 'mpg': $ctype='video/mpeg'; break;
    case 'avi': $ctype='video/x-msvideo'; break;
    default:    $ctype='application/force-download';
}

//check if http_range is sent by browser (or download manager)
if($is_resume && isset($_SERVER['HTTP_RANGE']))
{
    $arr = explode('=', $_SERVER['HTTP_RANGE'], 2);
    if(isset($arr[1]))   
        list($size_unit, $range_orig) = $arr;
    else list($size_unit) = $arr;

    if ($size_unit == 'bytes')
    {
        //multiple ranges could be specified at the same time, but for simplicity only serve the first range
        //http://tools.ietf.org/id/draft-ietf-http-range-retrieval-00.txt
        $arr3 = explode(',', $range_orig, 2);
        if(isset($arr3[1]))
            list($range, $extra_ranges) = $arr3;
        else
            list($range) = $arr3;
    }
    else
    {
        $range = '';
    }
}
else
{
    $range = '';
}

//figure out download piece from range (if set)
$arr2 = explode('-', $range, 2);
if(isset($arr2[1]))
    list($seek_start, $seek_end) = $arr2;
else
    list($seek_start) = $arr2;

//set start and end based on range (if set), else set defaults
//also check for invalid ranges.
$seek_end = (empty($seek_end)) ? ($size - 1) : min(abs(intval($seek_end)),($size - 1));
$seek_start = (empty($seek_start) || $seek_end < abs(intval($seek_start))) ? 0 : max(abs(intval($seek_start)),0);

//add headers if resumable
if ($is_resume)
{
    //Only send partial content header if downloading a piece of the file (IE workaround)
    if ($seek_start > 0 || $seek_end < ($size - 1))
    {
        header('HTTP/1.1 206 Partial Content');
    }

    header('Accept-Ranges: bytes');
    header('Content-Range: bytes '.$seek_start.'-'.$seek_end.'/'.$size);
}

//headers for IE Bugs (is this necessary?)
//header("Cache-Control: cache, must-revalidate");   
//header("Pragma: public");

header('Content-Type: ' . $ctype);
header('Content-Disposition: attachment; filename="' . $filename . '"');
header('Content-Length: '.($seek_end - $seek_start + 1));

//reset time limit for big files
set_time_limit(0);
ignore_user_abort(true);

//open the file
$fp = fopen($file, 'rb');

//seek to start of missing part
fseek($fp, $seek_start);

//start buffered download
while(!feof($fp))
{
    print(fread($fp, 1024*8));
    flush();
    ob_flush();        
}

fclose($fp);
exit;

Answer 1

我找到了解决办法！

我做了一个 htaccess RewriteRule。比如文件id是a1a2，文件名是foo.mp4，我把URL改成：download/a1a2/foo.mp4。

ht访问代码：

RewriteEngine on
RewriteRule ^download/(.*)/(.*)?$ download.php?id=$1&fileName=$2 [QSA,NC,L]

就这么简单！

Answer 2

您可以按照the official PHP manual here 中的说明设置适当的标头来做到这一点：

// We'll be outputting a PDF
header('Content-type: application/pdf');

// It will be called downloaded.pdf
header('Content-Disposition: attachment; filename="downloaded.pdf"');

也就是说，看看您的代码，您似乎已经在此处介绍了标头内容：

header('Content-Type: ' . $ctype);
header('Content-Disposition: attachment; filename="' . $filename . '"');
header('Content-Length: '.($seek_end - $seek_start + 1));

所以我认为唯一可能是问题与您的代码中的列表 mime 类型有关：

//This will set the Content-Type to the appropriate setting for the file
switch($file_extension)
{
    case 'exe': $ctype='application/octet-stream'; break;
    case 'zip': $ctype='application/zip'; break;
    case 'mp3': $ctype='audio/mpeg'; break;
    case 'mpg': $ctype='video/mpeg'; break;
    case 'avi': $ctype='video/x-msvideo'; break;
    default:    $ctype='application/force-download';
}

可能是浏览器或您使用的 IDM 下载软件无法识别您设置的 mime 类型（在您的代码中为：$ctype）。所以它默认为application/force-download。

我还强烈建议重构您的 switch，使其使用简单的关联数组逻辑像这样工作：

// This will set the Content-Type to the appropriate setting for the file
$ctype_array = array();
$ctype_array['exe'] = 'application/octet-stream';
$ctype_array['zip'] = 'application/zip';
$ctype_array['mp3'] = 'audio/mpeg';
$ctype_array['mpg'] = 'video/mpeg';
$ctype_array['avi'] = 'video/x-msvideo';

// Check if the file extension is in $ctype_array & return the value. If not, send default.
$ctype = array_key_exists($file_extension, $ctype_array) ? $ctype_array[$file_extension] : 'application/force-download';

这样您就可以轻松地向$ctype_array 添加更多项目，而无需处理switch/case 的逻辑。