PHP下载远程文件类(支持断点续传)

• PHP下载远程文件类支持断点续传
• 学习PHP下载远程文件类支

1.功能:支持断点续传的下载,能计算传输率,能控制传输率

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
      }
}
?>