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标题: php下载远程文件类--支持断点续传 (1) [打印本页]

作者: superadmin 时间: 2008-11-14 17:38
标题: php下载远程文件类--支持断点续传 (1)
1.功能:支持断点续传的下载,能计算传输率,能控制传输率
2.简易使用方法:

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

3.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
}

}

?>

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