CSS update class instance implemented by php

<?php 
/** css update class, update the version of the picture in the css file
 * Date: 2013-02-05
 * Author: fdipzone
 * Ver: 1.1
 *
 * Func:
 * update();
 *
 * Ver: 1.1 Add search_child parameter to traverse subfolders
 */ 
 
class CSSUpdate{ 
 
  private $csstmpl_path = null; 
  private $css_path = null; 
  private $replacetags = array(); 
  private $search_child = false; 
  private $convert_num = 0; 
  private $is_ready = 0; 
 
  /** Initialization
   * @param String $csstmpl_path css template path
   * @param String $css_path css target path
   * @param Array $replacetags The type of image that needs to be replaced
   * @param boolean $search_child Whether to traverse subfolders, default false
   */ 
  public function __construct($csstmpl_path, $css_path, $replacetags=array(), $search_child=false){ 
    if(!is_dir($csstmpl_path) || !is_dir($css_path) || !$replacetags){ 
      $this->is_ready = 0; 
    }else{ 
      $this->csstmpl_path = $csstmpl_path; 
      $this->css_path = $css_path; 
      $this->replacetags = $replacetags; 
      $this->search_child = $search_child; 
      $this->is_ready = 1; 
    } 
  } 
 
  /** Update css file */ 
  public function update(){ 
    if($this->is_ready==0){ 
      $this->response('csstmpl or csspath or replacetags error'); 
      return ''; 
    } 
    $this->traversing($this->csstmpl_path); 
    $this->response('covert num:'.$this->convert_num); 
  } 
 
  /** traversal folders
   * @param String $path file path
   */ 
  private function traversing($path){ 
    $handle = opendir($path); 
    while(($file=readdir($handle))!==false){ 
      if($file!='..' && $file!='.'){ 
        $curfile = $path.'/'.$file; 
         
        if(is_dir($curfile)){  // folder 
          if($this->search_child){  // Requires traversal of subfolders            $this->traversing($curfile); 
          } 
        }elseif($this->checkExt($curfile)){ // css file 
          $dfile = str_replace($this->csstmpl_path, $this->css_path, $curfile); 
          $this->create($curfile, $dfile); 
          $this->response($curfile.' convert to '.$dfile.' success'); 
          $this->convert_num ++; 
        } 
      } 
    } 
    closedir($handle); 
  } 
 
  /** Check file suffix */ 
  private function checkExt($file){ 
    $name = basename($file); 
    $namefrag = explode('.', $name); 
    if(count($namefrag)>=2){ 
      if(strtolower($namefrag[count($namefrag)-1])=='css'){ // css file        return true; 
      } 
    } 
    return false; 
  } 
 
  /** Replace the template content and write to csspath
   * @param String $tmplfile template file
   * @param String $dfile target file
   */ 
  private function create($tmplfile, $dfile){ 
    $css_content = file_get_contents($tmplfile); 
    foreach($this->replacetags as $tag){ 
      $css_content = str_replace($tag, $tag."?".date('YmdHis'), $css_content); 
    } 
    if(!is_dir(dirname($dfile))){  // Generate target path      mkdir(dirname($dfile), 0755, true); 
    } 
    file_put_contents($dfile, $css_content, true); 
  } 
 
  /** Output */ 
  private function response($content){ 
    echo $content."<br>"; 
  } 
} 
?>

<?php 
require_once ""; 
 
define('ROOT_PATH', dirname(__FILE__)); 
$css_path = ROOT_PATH.'/css'; 
$csstmpl_path = ROOT_PATH.'/csstmpl'; 
$replacetags = array('.png', '.jpg', '.gif'); 
 
$cssobj = new CSSUpdate($csstmpl_path, $css_path, $replacetags); 
$cssobj->update(); 
?>