A simple download script with resume and multi-part support

dl.php

<?php 
date_default_timezone_set('GMT');

//1- file we want to serve : 
$data_file = "/home/f0rud/Aalto Talk with Linus Torvalds [Full-length].mp4";

$data_size = filesize($data_file); //Size is not zero base

$mime = 'application/otect-stream'; //Mime type of file. to begin download its better to use this.
$filename = basename($data_file); //Name of file, no path included

//2- Check for request, is the client support this method?
if (isset($_SERVER['HTTP_RANGE']) || isset($HTTP_SERVER_VARS['HTTP_RANGE'])) {
    $ranges_str = (isset($_SERVER['HTTP_RANGE']))?$_SERVER['HTTP_RANGE']:$HTTP_SERVER_VARS['HTTP_RANGE'];
    $ranges_arr = explode('-', substr($ranges_str, strlen('bytes=')));
    //Now its time to check the ranges
    if ((intval($ranges_arr[0]) >= intval($ranges_arr[1]) && $ranges_arr[1] != "" && $ranges_arr[0] != "" )
        || ($ranges_arr[1] == "" && $ranges_arr[0] == "")
    ) {
        //Just serve the file normally request is not valid :( 
        $ranges_arr[0] = 0;
        $ranges_arr[1] = $data_size - 1;
    }
} else { //The client dose not request HTTP_RANGE so just use the entire file
    $ranges_arr[0] = 0;
    $ranges_arr[1] = $data_size - 1;
}

//Now its time to serve file 
$file = fopen($data_file, 'rb');

$start = $stop = 0;
if ($ranges_arr[0] === "") { //No first range in array
    //Last n1 byte
    $stop = $data_size - 1;
    $start = $data_size - intval($ranges_arr[1]);
} elseif ($ranges_arr[1] === "") { //No last
    //first n0 byte
    $start = intval($ranges_arr[0]);
    $stop = $data_size - 1;
} else {
    // n0 to n1
    $stop = intval($ranges_arr[1]);
    $start = intval($ranges_arr[0]);
}    
//Make sure the range is correct by checking the file

fseek($file, $start, SEEK_SET);
$start = ftell($file);
fseek($file, $stop, SEEK_SET);
$stop = ftell($file);

$data_len = $stop - $start;

//Lets send headers 

if (isset($_SERVER['HTTP_RANGE']) || isset($HTTP_SERVER_VARS['HTTP_RANGE'])) {
    header('HTTP/1.0 206 Partial Content');
    header('Status: 206 Partial Content');
}
header('Accept-Ranges: bytes');
header('Content-type: ' . $mime);
header('Content-Disposition: attachment; filename="' . $filename . '"'); 
header("Content-Range: bytes $start-$stop/" . $data_size );
header("Content-Length: " . ($data_len + 1));

//Finally serve data and done ~!
fseek($file, $start, SEEK_SET);
$bufsize = 2048000;

ignore_user_abort(true);
@set_time_limit(0);
while (!(connection_aborted() || connection_status() == 1) && $data_len > 0) {
    echo fread($file, $bufsize);
    $data_len -= $bufsize;
    flush();
}

fclose($file);

Thank you so much... It worked!

can i use this for vinaget source?
https://github.com/giaythuytinh176/vinaget-script

Hi,
$bufsize is what is this? And where is code limit the number of concurrent connections? And what is the code that determines download resume (support or not support download resume)?

Why does it stop working when the session starts?

For those who get invalid file format with this script, you should add ob_clean() in line66 after headers.

Line 9: a typo "otect-stream", should be "octet-stream".