解析php 版获取重定向后的地址(代码)

复制代码 代码如下:
//取重定向的地址
 class RedirectUrl{
     //地址
     var $url;
     //初始化地址
     function RedirectUrl($url){
         $this->url = $url;
     }
     /**
      * get_redirect_url()
      * 取重定向的地址
      *
      * @param string $url
      * @return string
      */
     private function get_redirect_url($url){
         $redirect_url = null;          $url_parts = @parse_url($url);
         if (!$url_parts) return false;
         if (!isset($url_parts["host"])) return false; //can"t process relative URLs
         if (!isset($url_parts["path"])) $url_parts["path"] = "/";          $sock = fsockopen($url_parts["host"], (isset($url_parts["port"]) ? (int)$url_parts["port"] : 80), $errno, $errstr, 30);
         if (!$sock) return false;          $request = "HEAD " . $url_parts["path"] . (isset($url_parts["query"]) ?"?".$url_parts["query"] : "") . " HTTP/1.1";
         $request .= "Host: " . $url_parts["host"] . "";
         $request .= "Connection: Close";
         fwrite($sock, $request);
         $response = "";
         while(!feof($sock)) $response .= fread($sock, 8192);
         fclose($sock);          if (preg_match("/^Location: (.+?)$/m", $response, $matches)){
             return trim($matches[1]);
         } else {
             return false;
         }
     }      /**
      * get_all_redirects()
      * 取所有重定向地址
      *
      * @param string $url
      * @return array
      */
     private function get_all_redirects($url){
         $redirects = array();
         while ($newurl = $this->get_redirect_url($url)){
             if (in_array($newurl, $redirects)){
                 break;
             }
             $redirects[] = $newurl;
             $url = $newurl;
         }
         return $redirects;
     }      /**
      * get_final_url()
      * 取实际地址
      *
      * @param string $url
      * @return string
      */
     function get_final_url(){
         $redirects = $this->get_all_redirects($this->url);          if (count($redirects)>0){
             return array_pop($redirects);
         } else {
             return $this->url;
         }
     }
 }  /**
  * get_show_pic
  * 取最终要显示的图片地址
  *
  * @param string $url
  * @return  string
  */
 function get_show_pic($url,$noimg ="noimg.gif",$newimg="http://special.ku6img.com/projects/2010/d-color/images/slt-1.jpg"){
     $obj = new RedirectUrl($url);      $realurl = $obj->get_final_url();      if(strpos($realurl,$noimg)>0){
         return $newimg;
     }
     return $url;
 }
 //参考
 echo "<img src="".get_show_pic("http://i2.ku6img.com/encode/picpath/2010/12/9/14/1294948410019/5.jpg").""/>";
 ?>