PHP 下载远程文件类(支持断点续传)

PHP 下载远程文件类,支持断点续传下载，代码内含有具体的调用说明。程序主要是使用 HTTP 协议下载文件，HTTP1.1协议必须指定文档结束后关闭链接,否则读取文档时无法使用feof判断结束，可以有两种使用方法，具体请下载查看源码。

<?php  /**   * 下载远程文件类支持断点续传    */  class HttpDownload {   private $m_url = "";    private $m_urlpath = "";    private $m_scheme = "http";    private $m_host = "";    private $m_port = "80";    private $m_user = "";    private $m_pass = "";    private $m_path = "/";    private $m_query = "";    private $m_fp = "";    private $m_error = "";   private $m_httphead = "" ;   private $m_html = "";      /**    * 初始化     */   public function PrivateInit($url){    $urls = "";    $urls = @parse_url($url);    $this->m_url = $url;    if(is_array($urls)) {     $this->m_host = $urls["host"];     if(!empty($urls["scheme"])) $this->m_scheme = $urls["scheme"];     if(!empty($urls["user"])) $this->m_user = $urls["user"];        if(!empty($urls["pass"])) $this->m_pass = $urls["pass"];        if(!empty($urls["port"])) $this->m_port = $urls["port"];        if(!empty($urls["path"])) $this->m_path = $urls["path"];        $this->m_urlpath = $this->m_path;     if(!empty($urls["query"])) {          $this->m_query = $urls["query"];          $this->m_urlpath .= "?".$this->m_query;         }      }   }      /**   * 打开指定网址   */   function OpenUrl($url) {    #重设各参数    $this->m_url = "";    $this->m_urlpath = "";    $this->m_scheme = "http";    $this->m_host = "";    $this->m_port = "80";    $this->m_user = "";    $this->m_pass = "";    $this->m_path = "/";    $this->m_query = "";    $this->m_error = "";    $this->m_httphead = "" ;    $this->m_html = "";    $this->Close();    #初始化系统    $this->PrivateInit($url);    $this->PrivateStartSession();   }     /**   * 获得某操作错误的原因   */   public function printError() {    echo "错误信息：".$this->m_error;    echo "具体返回头：<br>";    foreach($this->m_httphead as $k=>$v) {      echo "$k => $v <br>\r\n";     }   }      /**   * 判别用Get方法发送的头的应答结果是否正确   */   public function IsGetOK() {    if( ereg("^2",$this->GetHead("http-state")) ) {      return true;     } else {     $this->m_error .= $this->GetHead("http-state")." - ".$this->GetHead("http-describe")."<br>";     return false;    }   }      /**   * 看看返回的网页是否是text类型   */   public function IsText() {    if (ereg("^2",$this->GetHead("http-state")) && eregi("^text",$this->GetHead("content-type"))) {      return true;     } else {     $this->m_error .= "内容为非文本类型<br>";     return false;    }   }   /**   * 判断返回的网页是否是特定的类型   */   public function IsContentType($ctype) {    if (ereg("^2",$this->GetHead("http-state")) && $this->GetHead("content-type") == strtolower($ctype)) {      return true;     } else {     $this->m_error .= "类型不对 ".$this->GetHead("content-type")."<br>";     return false;    }   }      /**   * 用 HTTP 协议下载文件   */   public function SaveToBin($savefilename) {    if (!$this->IsGetOK()) return false;    if (@feof($this->m_fp)) {      $this->m_error = "连接已经关闭！";      return false;     }    $fp = fopen($savefilename,"w") or die("写入文件 $savefilename 失败！");    while (!feof($this->m_fp)) {     @fwrite($fp,fgets($this->m_fp,256));    }    @fclose($this->m_fp);    return true;   }      /**   * 保存网页内容为 Text 文件   */   public function SaveToText($savefilename) {    if ($this->IsText()) {     $this->SaveBinFile($savefilename);    } else {     return "";    }   }      /**   * 用 HTTP 协议获得一个网页的内容   */   public function GetHtml() {    if (!$this->IsText()) return "";    if ($this->m_html!="") return $this->m_html;    if (!$this->m_fp||@feof($this->m_fp)) return "";    while(!feof($this->m_fp)) {     $this->m_html .= fgets($this->m_fp,256);    }    @fclose($this->m_fp);    return $this->m_html;   }      /**   * 开始 HTTP 会话   */   public function PrivateStartSession() {    if (!$this->PrivateOpenHost()) {     $this->m_error .= "打开远程主机出错!";     return false;    }    if ($this->GetHead("http-edition")=="HTTP/1.1") {     $httpv = "HTTP/1.1";    } else {     $httpv = "HTTP/1.0";    }    fputs($this->m_fp,"GET ".$this->m_urlpath." $httpv\r\n");    fputs($this->m_fp,"Host: ".$this->m_host."\r\n");    fputs($this->m_fp,"Accept: */*\r\n");    fputs($this->m_fp,"User-Agent: Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.2)\r\n");    #HTTP1.1协议必须指定文档结束后关闭链接,否则读取文档时无法使用feof判断结束    if ($httpv=="HTTP/1.1") {     fputs($this->m_fp,"Connection: Close\r\n\r\n");    } else {     fputs($this->m_fp,"\r\n");    }    $httpstas = fgets($this->m_fp,256);    $httpstas = split(" ",$httpstas);    $this->m_httphead["http-edition"] = trim($httpstas[0]);    $this->m_httphead["http-state"] = trim($httpstas[1]);    $this->m_httphead["http-describe"] = "";    for ($i=2;$i<count($httpstas);$i++) {     $this->m_httphead["http-describe"] .= " ".trim($httpstas[$i]);    }    while (!feof($this->m_fp)) {     $line = str_replace("\"","",trim(fgets($this->m_fp,256)));     if($line == "") break;     if (ereg(":",$line)) {      $lines = split(":",$line);      $this->m_httphead[strtolower(trim($lines[0]))] = trim($lines[1]);     }    }   }      /**   * 获得一个Http头的值   */   public function GetHead($headname) {    $headname = strtolower($headname);    if (isset($this->m_httphead[$headname])) {     return $this->m_httphead[$headname];    } else {     return "";    }   }      /**   * 打开连接   */   public function PrivateOpenHost() {    if ($this->m_host=="") return false;    $this->m_fp = @fsockopen($this->m_host, $this->m_port, &$errno, &$errstr,10);    if (!$this->m_fp){     $this->m_error = $errstr;     return false;    } else {     return true;    }   }      /**   * 关闭连接   */   public function Close(){    @fclose($this->m_fp);   }  }    #两种使用方法，分别如下：    #打开网页  $httpdown = new HttpDownload();  $httpdown->OpenUrl("http://www.google.com.hk");  echo $httpdown->GetHtml();  $httpdown->Close();      #下载文件  $file = new HttpDownload(); # 实例化类  $file->OpenUrl("http://www.ti.com.cn/cn/lit/an/rust020/rust020.pdf"); # 远程文件地址  $file->SaveToBin("rust020.pdf"); # 保存路径及文件名  $file->Close(); # 释放资源  ?>