http range php

http://stackoverflow.com/questions/157318/resumable-downloads-when-using-php-to-send-the-file

$filesize = filesize($file);

$offset = 0;
$length = $filesize;

if ( isset($_SERVER['HTTP_RANGE']) ) {
        // if the HTTP_RANGE header is set we're dealing with partial content

        $partialContent = true;

        // find the requested range
        // this might be too simplistic, apparently the client can request
        // multiple ranges, which can become pretty complex, so ignore it for now
        preg_match('/bytes=(\d+)-(\d+)?/', $_SERVER['HTTP_RANGE'], $matches);

        $offset = intval($matches[1]);
        $length = intval($matches[2]) - $offset;
} else {
        $partialContent = false;
}

$file = fopen($file, 'r');

// seek to the requested offset, this is 0 if it's not a partial content request
fseek($file, $offset);

$data = fread($file, $length);

fclose($file);

if ( $partialContent ) {
        // output the right headers for partial content

        header('HTTP/1.1 206 Partial Content');

        header('Content-Range: bytes ' . $offset . '-' . ($offset + $length) . '/' . $filesize);
}

// output the regular HTTP headers
header('Content-Type: ' . $ctype);
header('Content-Length: ' . $filesize);
header('Content-Disposition: attachment; filename="' . $fileName . '"');
header('Accept-Ranges: bytes');

// don't forget to send the data too