php 網域名稱處理函數

下面這款個一個是判斷輸入的網域名稱是不是合法的，然後再把http,https,ftp進行處理，分析再發送

function _scan_url()
   {
       $req = $this->_url;
      
       $pos = strpos($req, '://');
       $this->_protocol = strtolower(substr($req, 0, $pos));
      
       $req = substr($req, $pos+3);
       $pos = strpos($req, '/');
       if($pos === false)
           $pos = strlen($req);
       $host = substr($req, 0, $pos);
      
       if(strpos($host, ':') !== false)
       {
           list($this->_host, $this->_port) = explode(':', $host);
       }
       else
       {
           $this->_host = $host;
           $this->_port = ($this->_protocol == 'https') ? 443 : 80;
       }
      
       $this->_uri = substr($req, $pos);
       if($this->_uri == '')
           $this->_uri = '/';
   }

function cleanDomain($q,$w=0){ //整理網域名稱 $w=1過濾www.首碼 $w=0不過濾
 $q = htmlspecialchars(strtolower(trim($q)));
 if(substr($q,0,7) == "http://" || substr($q,0,8) == "https://" || substr($q,0,6) == "ftp://"){
  $q = str_replace("http:/","",$q);
  $q = str_replace("https:/","",$q);
  $q = str_replace("ftp:/","",$q);
 }
 if(substr($q,0,4) == "www." && $w==1) {
  $q = str_replace("www.","",$q);
 }
 $q = trim($q,"/");
 return $q;
}