Limit download speed using PHP

I tried my hand at a custom class that can help you deal with rate limiting downloads, you could try the following?

class Downloader {
     private $file_path;
     private $downloadRate;
     private $file_pointer;
     private $error_message;
     private $_tickRate = 4; // Ticks per second.
     private $_oldMaxExecTime; // saving the old value.
     function __construct($file_to_download = null) {
        $this->_tickRate = 4;
        $this->downloadRate = 1024; // in Kb/s (default: 1Mb/s)
        $this->file_pointer = 0; // position of current download.
        $this->setFile($file_to_download);
     }  
     public function setFile($file) {
        if (file_exists($file) && is_file($file))
           $this->file_path = $file;
        else 
           throw new Exception("Error finding file ({$this->file_path}).");
     }
     public function setRate($kbRate) {
        $this->downloadRate = $kbRate;
     }
     private function sendHeaders() {
        if (!headers_sent($filename, $linenum)) {
           header("Content-Type: application/octet-stream");
           header("Content-Description: file transfer");
           header('Content-Disposition: attachment; filename="' . $this->file_path . '"');
           header('Content-Length: '. $this->file_path);
        } else {
           throw new Exception("Headers have already been sent. File: {$filename} Line: {$linenum}");
        }
     }
     public function download() {
        if (!$this->file_path) {
           throw new Exception("Error finding file ({$this->file_path}).");
        }
        flush();    
        $this->_oldMaxExecTime = ini_get('max_execution_time');
        ini_set('max_execution_time', 0);
        $file = fopen($this->file_path, "r");     
        while(!feof($file)) {
           print fread($file, ((($this->downloadRate*1024)*1024)/$this->_tickRate);    
           flush();
           usleep((1000/$this->_tickRate)); 
        }    
        fclose($file);
        ini_set('max_execution_time', $this->_oldMaxExecTime);
        return true; // file downloaded.
     }
  }

I've hosted the file as a gist aswell on github here. - https://gist.github.com/3687527

Downloader class is good but have one problem if you have two downloads at same time, you will lose max_execution_time value.

Some example:

Download first file(size = 1mb; download time 100 seconds )

After one second download second file ( size = 100 mb; dowload time = 10000 seconds)

First download set max_execution_time to 0

Second remeber _oldMaxExecTime as 0

First download end and return max_execution_time to old value

Second download end and return max_execution time to 0

The reason your download stops after 5MB is because it takes over 60 seconds to download 5MB at 80KB/s. Most of those "speed limiter" scripts use sleep() to pause for a while after sending a chunk, resume, send another chunk, and pause again. But PHP will automatically terminate a script if it's been running for a minute or more. When that happens, your download stops.

You can use set_time_limit() to prevent your script from being terminated, but some web hosts will not allow you to do this. In that case you're out of luck.

A second is too much time, it will make clients think that the server is unresponsive and prematurely end the download. Change sleep(1) to usleep(200):

set_time_limit(0);

$file = array();
$file['name'] = 'file.mp4';
$file['size'] = filesize($file['name']);

header('Content-Type: application/octet-stream');
header('Content-Description: file transfer');
header('Content-Disposition: attachment; filename="' . $file['name'] . '"');
header('Content-Length: '. $file['size']);

$open = fopen($file['name'], 'rb');
while( !feof($open) ){
    echo fread($open, 256);
    usleep(200);
}
fclose($open);