PHP - Drive-by Downloads

Hi all,

I've tried many, many variations of php download script using readfile() fread() fpassthru() etc... but none seem reliable. I can download small files perfectly fine, but say I have a 30 or 90mb zip file the download ocassionally bombs out and says the download is complete even though the full file hasn't been transferred.
I have tired it on several browsers with pretty much the same issue. The interesting bit for me is that if I download the same file across different browsers (whether or not they start at the same time or not) on my computer the download stops at the same time (not same point into download) for each browser.  Its as if the connection is being reset on my website on a global basis...

The important part of my script as it is at the moment:

Code: [Select]
// resumable download?
$is_resume = TRUE;

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

@ini_set('magic_quotes_runtime', 0);
set_time_limit(0);
apache_setenv('no-gzip', '1');
mb_http_output("pass");

// required for IE, otherwise Content-disposition is ignored
if(ini_get('zlib.output_compression')) { ini_set('zlib.output_compression', 'Off'); }
 
//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
$filename = (strstr($_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 'zip': $ctype='application/zip'; break;
        case 'pdf': $ctype='application/pdf'; break;
        default:    $ctype='application/force-download';
    }

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

    //figure out download piece from range (if set)
    list($seek_start, $seek_end) = explode('-', $range, 2);

    //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);
    }

    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));

    //open the file
    $fp = fopen($path, 'rb');
    //seek to start of missing part
    fseek($fp, $seek_start);

    //start buffered download
    while(!feof($fp)) {
        //reset time limit for big files
        set_time_limit(0);
        print(fread($fp, 1024*8));
        flush();
        ob_flush();
    }
    fclose($fp);
exit();

I did have the following section in replace of the above fread section up until this morning (but same issue):

Code: [Select]
// http headers for zip downloads
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: public");
header("Content-Description: File Transfer");
header("Content-type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"".$filename."\"");
header("Content-Transfer-Encoding: binary");
header('Content-Length: '.$size);
ob_end_flush();
@readfile($path);

I have tried different headers and so forth, but all generally seem to bomb out occassionally before the download completes. But they don't bomb out at a particular point in the file size (ie at 25mb). Just seems to work and then die at the same time across different browsers, even when they are started at different times.

Very strange and I've spent days modifying the script and still no answers. Sometimes the files download fine, but bomb out too many times for it to be satifactory to leave.

Any help or pointers would be much appreciated.

Is there a way (in PHP) to prompt to download file regardless of it's type?  I have taken someone's suggestions and put files in a folder with HTAccess protection. ALL I want
to do is just grab the files and prompt download (regardless of what the type of file is), is there an easy way to do this in PHP.

I'm creating a CSV file on the fly for download in the backend - a stock management function.

The script works fine extracting from the database fine and creates the CSV. But the next step of the script is to download the file using:

header('Content-type: application/octet-stream');
header('Content-Disposition: attachment; filename="' . $filename . '"');

This works, in as much as it downloads the file specified by $filename but when I open the file it's empty and the File Size in properties is 0.

But if I go into my FTP and download the file it contains all the data as expected?


Anyone have any ideas whats wrong? Thoughts I've had:
File size too large would using ob_start('ob_gzhandler'); help? Or is there an INI setting?
File encoding needs to be set? UTF8?
Content Type should be text/csv?

Thanks

Hi !

I am currently trying to develop a PHP application in which my server downloads a file and the user can do the same almost simultaneously. I already think about the problem "If the user downloads fastly than the server...", but it's not a problem at this moment.
To do so, I used the header and readfile functions of php. Here is my code :

Code: [Select]
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.$data['name'].'";');
header('Content-Transfer-Encoding: binary');
header('Content-Length: '.$data['size']);
readfile($remoteFile);

I must to use the Content-length header to set the proper size of the file and not the size that is downloaded when the user clicks on the link. However, after some seconds or minutes, download is stopped and I need to restart...
If you think about a solution, even if it didn't use the header(); function, please tell me.

Thank you in advance...

This upload form code works successfully, where a file is chosen, renamed and stored in the 'upload' folder,