A class which is good for downloading files

最新推荐文章于 2025-05-11 22:38:37 发布

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最新推荐文章于 2025-05-11 22:38:37 发布

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分类专栏： php 文章标签： class header function server authentication download

本文链接：https://blog.youkuaiyun.com/zzz_781111/article/details/2859369

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本文介绍了一个支持断点续传功能的下载器类实现，该下载器能够根据客户端请求进行部分文件传输，并且可以控制传输速率。适用于HTTP下载场景。

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1.作者: Nguyen Quoc Bao quocbao.coder@gmail.com

2.功能:支持断点续传的下载,能计算传输率,能控制传输率

3.简易使用方法:

$object = new httpdownload();
$object->set_byfile($file);//服务器文件名,包括路径
$object->filename = $filename;//下载另存为的文件名
$object->download();

4.源文件:

class httpdownload {

var $data = null;
var $data_len = 0;
var $data_mod = 0;
var $data_type = 0;
var $data_section = 0; //section download
var $sentSize=0;

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;
var $totalsizeref = 0;

var $bandwidth = 0;

var $speed = 0;

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;
  }
  $this->sentSize=0;

  return true;
}

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;
}

function download() {
  if (!$this->initialize()) return false;

try
{

error_log("begin download/n", 3,"/usr/local/www/apache22/LOGS/apache22_php.err");

   $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;
      $this->sentSize+=$size;

     }
     else
     {
      echo fread($res , $bufsize);
      $this->bandwidth += $bufsize;
      $this->sentSize+=$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;

      $this->sentSize+=$size;
     }
     else
     {
      $this->bandwidth += $bufsize;
      $this->sentSize+=$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($this->totalsizeref==$this->sentSize )error_log("end download/n", 3,"/usr/local/www/apache22/LOGS/apache22_php.err");
   else error_log("download is canceled/n", 3,"/usr/local/www/apache22/LOGS/apache22_php.err");

if ($this->use_autoexit) exit();

   //restore old status
   ignore_user_abort($old_status);
   set_time_limit(ini_get("max_execution_time"));

  }
  catch(Exception $e)
  {

    error_log("cancel download/n".$e, 3,"/usr/local/www/apache22/LOGS/apache22_php.err");

}
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);
   $this->totalsizeref = filesize($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;
}

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
}

}