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php 断点续传功能

断点续传指的是在上传时,将上传任务(一个文件或一个压缩包)人为的划分为几个部分,每一个部分采用一个线程进行上传,下面我们来看看php 断点续传功能的实现方法吧。

<?php
/**
    * 作者 于恩水<yuenshui@126.com>
    * 支持断点续传下载
    * 实例代码:
    *           $down = new SD_DownLoad();
    *          $down->Down('E:/iso/MS.Office2003SP1.CHS.iso');
    **/
class SD_DownLoad {
    
     /**
         * 下载的开始点
         *
         * @access private
         * @var integer
         */
     private $mDownStart;
    
     /**
         * 文件大小
         *
         * @access private
         * @var integer
         */
     private $mFileSize;
    
     /**
         * 文件句柄
         *
         * @access private
         * @var integer
         */
     private $mFileHandle;
    
     /**
         * 文件全路径
         *
         * @access private
         * @var string
         */
     private $mFilePath;
    
     /**
         * 文件下载时显示的文件名
         *
         * @access private
         * @var string
         */
     private $mFileName;
    
     /**
         * 构造函数
         *
         * @access public
         * @return void
         **/
     public function __construct() {
     }
    
     /**
         * 下载
         *
         * @param string $pFilePath 文件全路径
         * @param string pFileName 文件下载时显示的文件名,缺省为实际文件名
         * @access public
         * @return void
         **/
     public function Down($pFilePath, $pFileName = '') {
          $this->mFilePath = $pFilePath;
          if(!$this->IniFile()) $this->SendError();
          $this->mFileName = empty($pFileName) ? $this->GetFileName() : $pFileName;
         
          $this->IniFile();
          $this->SetStart();
          $this->SetHeader();
         
          $this->Send();
     }

    
     /**
         * 初始化文件信息
         *
         * @access private
         * @return boolean
         **/
     private function IniFile() {
          if(!is_file($this->mFilePath)) return false;
          $this->mFileHandle = fopen($this->mFilePath, 'rb');
          $this->mFileSize = filesize($this->mFilePath);
          return true;
     }
    
     /**
         * 设置下载开始点
         *
         * @access private
         * @return void
         **/
     private function SetStart() {
          if (!empty($_SERVER['HTTP_RANGE']) && preg_match("/^bytes=([d]?)-([d]?)$/i", $_SERVER['HTTP_RANGE'], $match)) {
               if(empty($match[1])) $this->mDownStart = $match[1];
               fseek($this->mFileHandle, $this->mDownStart);
          }
          else {
               $this->mDownStart = 0;
          }
     }
    
     /**
         * 设置http头
         *
         * @access private
         * @return void
         **/
     private function SetHeader() {
          @header("Cache-control: public");
          @header("Pragma: public");
          Header("Content-Length: " . ($this->mFileSize - $this->mDownStart));
          if ($this->mDownStart > 0) {
               @Header("HTTP/1.1 206 Partial Content");
               Header("Content-Ranges: bytes" . $this->mDownStart . "-" . ($this->mFileSize - 1) . "/" . $this->mFileSize);
          }
          else {
               Header("Accept-Ranges: bytes");
          }
          @header("Content-Type: application/octet-stream");
          @header("Content-Disposition: attachment;filename=" . $this->mFileName);
     }
    
     /**
         * 获取全路径里的文件名部分
         *
         * @access private
         * @return string
         **/
     private function GetFileName() {
          return basename ($this->mFilePath);
     }
    
     /**
         * 发送数据
         *
         * @access private
         * @return void
         **/
     private function Send() {
          fpassthru($this->mFileHandle);
     }
    
     /**
         * 发送错误
         *
         * @access public
         * @return void
         **/
     public function SendError() {
          @header("HTTP/1.0 404 Not Found");
          @header("Status: 404 Not Found");
          exit();
     }
}
?>

补充:Php教程,Php高级应用
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