php获取CSS文件中图片地址并下载到本地的方法

/ 
获取CSS中图片地址,并且保存到本地 
/
class getInCssImage
{   
        / 
           图片保存下来
         @param $cssUrl css的url地址
         @param $dir 保存图片的目录
         @return void
         /
        static public function saveImage($cssUrl, $dir)
        {   
            $content = file_get_contents($cssUrl);  
            $patterns = '/images(.).(jpg|gif|png)/'; //正则根据不同地址需要变换
            preg_match_all($patterns, $content, $matches);
            $imagesUrls = $matches[0];
            if (!is_dir($dir))
                mkdir(dirname(__FILE__). '/'. $dir, 0777);
            foreach($imagesUrls as $image)
            {   
                ob_start();
                $imageUrl = "http://.xxxx./".$image; //这个地址填入你想要抓取的地址
                readfile($imageUrl);
                $img  = ob_get_contents();
                ob_end_clean();
                $size = strlen($img);
                $localImage = $dir. strchr($image, '/'); //存到本地的图片地址
                $fp = fopen($localImage, 'a');
                fwrite($fp, $img);
                fclose($fp);
            }   
        }   
}
$content = getInCssImage::saveImage('/css/css.css', 'image');