php实现远程文件下载代码

class download
{
    var http://pic4.phprm.com/2010/07/22/http://pic4.phprm.com/2010/07/22/$url.jpg.jpg;//远程文件地址

    var $file_name = "hdwiki.zip";//下载来的文件名称

    var $save_path = "./www.phprm.com";//下载到本地的文件路径

    var $localfile;//下载到本地文件的路径和名称

    var $warning;//警告信息

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    var $redown=0;//是否重新下载

    /*初始化*/
    function seturl($url)
    {
         if(!empty($url))$this->url = $url;
    }

    function setfilename($file_name)
    {
     if(!empty($file_name))$this->file_name = $file_name;
    }

    function setsavepath($save_path)
    {
     if(!empty($save_path))$this->save_path = $save_path;
    }

    function setredown($redown)
    {
     if(!empty($redown))$this->redown = $redown;
    }

    function download($url, $redown = 0, $save_path = 0, $file_name = 0)
    {
        $this->seturl($url);
        $this->setfilename($file_name);
        $this->setsavepath($save_path);
        $this->setredown($redown);
        if(!file_exists($this->save_path))
        {
            $dir = explode("/",$this->save_path);
            foreach($dir as $p)
            mkdir($p);
        }
   }
  
    /* 检查url合法性函数 */
    function checkurl(){
        return preg_match("/^(http|ftp)(://)([a-za-z0-9-_]+[./]+[w-_/]+.*)+$/i", $this->url);
    }

    //下载文件到本地

    function downloadfile()
    {
        //检测变量

        $this->localfile = $this->save_path."/".$this->file_name;
         if($this->url == "" || $this->localfile == ""){
                 $this->warning = "error: 变量设置错误.";
             return $this->warning;
        }

        if (!$this->checkurl()){
            $this->warning = "error: url ". $this->url ." 不合法.";
               return $this->warning;
            }

        if (file_exists($this->localfile)){
            if($this->redown)
            {
                unlink($this->localfile);
            }
            else
            {
                $this->warning = "warning: 升级文件 ". $this->localfile ." 已经存在！ 重新下载";
                return $this->warning;
             //exit("error: 本地文件 ". $this->localfile ." 已经存在,请删除或改名后重新运行本程序.");

            }
        }

        //打开远程文件

        $fp = fopen($this->url, "rb");
        if (!$fp){
            $this->warning = "error: 打开远程文件 ". $this->url ." 失败.";
             return $this->warning;
        }

     //打开本地文件

     $sp = fopen($this->localfile, "wb");
     if (!$sp){
         $this->warning = "error: 打开本地文件 ". $this->localfile ." 失败.";
         return $this->warning;
     }

     //下载远程文件

     //echo "正在下载远程文件，请等待";

     while (!feof($fp)){
     $tmpfile .= fread($fp, 1024);
     //echo strlen($tmpfile);

     }
       //保存文件到本地

       fwrite($sp, $tmpfile);
     fclose($fp);
     fclose($sp);
    
     if($this->redown)
             $this->warning = "success: 重新下载文件 ". $this->file_name ." 成功";
     else
             $this->warning = "success: 下载文件 ". $this->file_name ." 成功";
             
     return $this->warning;
    }
}