How to calculate a user have downloaded how much from servers in my file in php
<p>I am a newbie in php and making a script were i need to count the bandwidth downloaded from my users .
i have to store some file of my users and provide them a resumable download support to them but also count how much bandwidth downloaded and who have downloaded .</p>

<p><pre><code>
function output_file($file, $name, $mime_type=''){
 /*
 This function takes a path to a file to output ($file), 
 the filename that the browser will see ($name) and 
 the MIME type of the file ($mime_type, optional).</p>

<p>If you want to do something on download abort/finish,
 register_shutdown_function('function_name');
 */
 if(!is_readable($file)) die('File not found or inaccessible!');</p>

<p>$size = filesize($file);
 $name = rawurldecode($name);</p>

<p>/* Figure out the MIME type (if not specified) */
 $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"
 );</p>

<p>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";
     };
 };</p>

<p>@ob_end_clean(); //turn off output buffering to decrease cpu usage</p>

<p>// required for IE, otherwise Content-Disposition may be ignored
 if(ini_get('zlib.output_compression'))
  ini_set('zlib.output_compression', 'Off');</p>

<p>header('Content-Type: ' . $mime_type);
 header('Content-Disposition: attachment; filename="'.$name.'"');
 header("Content-Transfer-Encoding: binary");
 header('Accept-Ranges: bytes');</p>

<p>/* The three lines below basically make the 
    download non-cacheable */
 header("Cache-control: private");
 header('Pragma: private');
 header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");</p>

<p>// multipart-download and download resuming support
 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);
    }</p>

<pre><code>$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");
</code></pre>

<p>} else {
    $new_length=$size;
    header("Content-Length: ".$size);
 }</p>

<p>/* output the file itself <em>/
 $chunksize = 1</em>(1024*1024); //you may want to change this
 $bytes_send = 0;
 if ($file = fopen($file, 'r'))
 {
    if(isset($_SERVER['HTTP_RANGE']))
    fseek($file, $range);</p>

<pre><code>while(!feof($file) &amp;&amp; 
    (!connection_aborted()) &amp;&amp; 
    ($bytes_send&lt;$new_length)
      )
{
    $buffer = fread($file, $chunksize);
    print($buffer); //echo($buffer); // is also possible
    flush();
    $bytes_send += strlen($buffer);
}
</code></pre>

<p>fclose($file);
 } else die('Error - can not open file.');</p>

<p>die();
}</p>

<p>if($_REQUEST['d']){
$hk = $_REQUEST['d'];
output_file('files/'.$_COOKIE['acc_inf'].'/'.$hk,$hk); 
}</p>

<p>?>
</pre></code></p>

<p>Now , for example if a user named "john" uploaded 1 file name "test.rar" (2 GB ) now hw wants to download it</p>

<p>then <a href="http://exaple.com/download.php?d=test.rar" rel="nofollow">http://exaple.com/download.php?d=test.rar</a> the file exists on folder named john/test.rar that was ok .</p>

<p>but i have count how much badwith he have used while downloading and save it to a database i dont want to count it as count or click count like he is starteted downloed that file of 2 gb and download 900 MB it my database should updated every realtime deatils .</p>

<p>Please help me how to count how much bandwith is being downloaded ..</p>

<p>thanks</p>
