class.httpdownload.php

<?php

/** 
@author Nguyen Quoc Bao <quocbao.coder@gmail.com> 
@version 1.3 
@desc A simple object for processing download operation , support section downloading 
Please send me an email if you find some bug or it doesn't work with download manager. 
I've tested it with 
   - Reget 
   - FDM 
   - FlashGet 
   - GetRight 
   - DAP 
@copyright It's free as long as you keep this header . 
@example 
1: File Download 
   $object = new downloader; 
   $object->set_byfile($filename); //Download from a file 
   $object->use_resume = true; //Enable Resume Mode 
   $object->download(); //Download File 
2: Data Download 
$object = new downloader; 
   $object->set_bydata($data); //Download from php data 
   $object->use_resume = true; //Enable Resume Mode 
   $object->set_filename($filename); //Set download name 
   $object->set_mime($mime); //File MIME (Default: application/otect-stream) 
   $object->download(); //Download File 
   3: Manual Download 
   $object = new downloader; 
   $object->set_filename($filename); 
$object->download_ex($size); 
//output your data here , remember to use $this->seek_start and $this->seek_end value :) 
**/  
class httpdownload {  
var $data = null;  
var $data_len = 0;  
var $data_mod = 0;  
var $data_type = 0;  
var $data_section = 0; //section download  
/** 
* @var ObjectHandler 
**/  
var $handler = array('auth' => null);  
var $use_resume = true;  
var $use_autoexit = false;  
var $use_auth = false;  
var $filename = null;  
var $mime = null;  
var $bufsize = 2048;  
var $seek_start = 0;  
var $seek_end = -1;  
/** 
* Total bandwidth has been used for this download 
* @var int 
*/  
var $bandwidth = 0;  
/** 
* Speed limit 
* @var float 
*/  
var $speed = 0;  
/*------------------- 
| Download Function | 
-------------------*/  
/** 
* Check authentication and get seek position 
* @return bool 
**/  
function initialize() {  
   global $HTTP_SERVER_VARS;  
   if ($this->use_auth) //use authentication  
   {  
    if (!$this->_auth()) //no authentication  
    {  
     header('WWW-Authenticate: Basic realm="Please enter your username and password"');  
       header('HTTP/1.0 401 Unauthorized');  
       header('status: 401 Unauthorized');  
       if ($this->use_autoexit) exit();  
     return false;  
    }  
   }  
   if ($this->mime == null) $this->mime = "application/octet-stream"; //default mime  
   if (isset($_SERVER['HTTP_RANGE']) || isset($HTTP_SERVER_VARS['HTTP_RANGE']))  
   {  
    if (isset($HTTP_SERVER_VARS['HTTP_RANGE'])) $seek_range = substr($HTTP_SERVER_VARS['HTTP_RANGE'] , strlen('bytes='));  
    else $seek_range = substr($_SERVER['HTTP_RANGE'] , strlen('bytes='));  
    $range = explode('-',$seek_range);  
    if ($range[0] > 0)  
    {  
     $this->seek_start = intval($range[0]);  
    }  
    if ($range[1] > 0) $this->seek_end = intval($range[1]);  
    else $this->seek_end = -1;  
    if (!$this->use_resume)  
    {  
     $this->seek_start = 0;  
     //header("HTTP/1.0 404 Bad Request");  
     //header("Status: 400 Bad Request");  
     //exit;  
     //return false;  
    }  
    else  
    {  
     $this->data_section = 1;  
    }  
   }  
   else  
   {  
    $this->seek_start = 0;  
    $this->seek_end = -1;  
   }  
   return true;  
}  
/** 
* Send download information header 
**/  
function header($size,$seek_start=null,$seek_end=null) {  
   
   header('Content-type: ' . $this->mime);  
   header('Content-Disposition: attachment; filename="' . $this->filename . '"');  
   header('Last-Modified: ' . date('D, d M Y H:i:s /G/M/T' , $this->data_mod));  

   if ($this->data_section && $this->use_resume)  
   {  
    header("HTTP/1.0 206 Partial Content");  
    header("Status: 206 Partial Content");  
    header('Accept-Ranges: bytes');  
    header("Content-Range: bytes $seek_start-$seek_end/$size");  
    header("Content-Length: " . ($seek_end - $seek_start + 1));  
   }  
   else  
   {  
    header("Content-Length: $size");  
   }  
}  
function download_ex($size)  
{  
   if (!$this->initialize()) return false;  
   ignore_user_abort(true);  
   //Use seek end here  
   if ($this->seek_start > ($size - 1)) $this->seek_start = 0;  
   if ($this->seek_end <= 0) $this->seek_end = $size - 1;  
   $this->header($size,$seek,$this->seek_end);  
   $this->data_mod = time();  
   return true;  
}  
/** 
* Start download 
* @return bool 
**/  
function download() {  
   if (!$this->initialize()) return false;  
   $seek = $this->seek_start;  
   $speed = $this->speed;  
   $bufsize = $this->bufsize;  
   $packet = 1;  
   //do some clean up  
   @ob_end_clean();  
   $old_status = ignore_user_abort(true);  
   @set_time_limit(0);  
   $this->bandwidth = 0;  
   $size = $this->data_len;  
   if ($this->data_type == 0) //download from a file  
   {  
    $size = filesize($this->data);  
    if ($seek > ($size - 1)) $seek = 0;  
    if ($this->filename == null) $this->filename = basename($this->data); 
    $res = fopen($this->data,'rb');  
    if ($seek) fseek($res , $seek);  
    if ($this->seek_end < $seek) $this->seek_end = $size - 1;  
    $this->header($size,$seek,$this->seek_end); //always use the last seek  
    $size = $this->seek_end - $seek + 1;  
    while (!(connection_aborted() || connection_status() == 1) && $size > 0)  
    {  
     if ($size < $bufsize)  
     {  
      echo fread($res , $size);  
      $this->bandwidth += $size;  
     }  
     else  
     {  
      echo fread($res , $bufsize);  
      $this->bandwidth += $bufsize;  
     }  
     $size -= $bufsize;  
     flush();  
     if ($speed > 0 && ($this->bandwidth > $speed*$packet*1024))  
     {  
      sleep(1);  
      $packet++;  
     }  
    }  
    fclose($res);  
   }  
   elseif ($this->data_type == 1) //download from a string  
   {  
    if ($seek > ($size - 1)) $seek = 0;  
    if ($this->seek_end < $seek) $this->seek_end = $this->data_len - 1;  
    $this->data = substr($this->data , $seek , $this->seek_end - $seek + 1);  
    if ($this->filename == null) $this->filename = time();  
    $size = strlen($this->data);  
    $this->header($this->data_len,$seek,$this->seek_end);  
    while (!connection_aborted() && $size > 0) {  
     if ($size < $bufsize)  
     {  
      $this->bandwidth += $size;  
     }  
     else  
     {  
      $this->bandwidth += $bufsize;  
     }  
     echo substr($this->data , 0 , $bufsize);  
     $this->data = substr($this->data , $bufsize);  
     $size -= $bufsize;  
     flush();  
     if ($speed > 0 && ($this->bandwidth > $speed*$packet*1024))  
     {  
      sleep(1);  
      $packet++;  
     }  
    }  
   } else if ($this->data_type == 2) {  
    //just send a redirect header  
    header('location: ' . $this->data);  
   }  
   if ($this->use_autoexit) exit();  
   //restore old status  
   ignore_user_abort($old_status);  
   set_time_limit(ini_get("max_execution_time"));  
   return true;  
}  
function set_byfile($dir) {  
   if (is_readable($dir) && is_file($dir)) {  
    $this->data_len = 0;  
    $this->data = $dir;  
    $this->data_type = 0;  
    $this->data_mod = filemtime($dir);  
    return true;  
   } else return false;  
}  
function set_bydata($data) {  
   if ($data == '') return false;  
   $this->data = $data;  
   $this->data_len = strlen($data);  
   $this->data_type = 1;  
   $this->data_mod = time();  
   return true;  
}  
function set_byurl($data) {  
   $this->data = $data;  
   $this->data_len = 0;  
   $this->data_type = 2;  
   return true;  
}  
function set_lastmodtime($time) {  
   $time = intval($time);  
   if ($time <= 0) $time = time();  
   $this->data_mod = $time;  
}  
/** 
* Check authentication 
* @return bool 
**/  
function _auth() {  
   if (!isset($_SERVER['PHP_AUTH_USER'])) return false;  
   if (isset($this->handler['auth']) && function_exists($this->handler['auth']))  
   {  
    return $this->handler['auth']('auth' , $_SERVER['PHP_AUTH_USER'],$_SERVER['PHP_AUTH_PW']);  
   }  
   else return true; //you must use a handler  
}  
}  

?>