Php小技巧备忘--获取域名

function get_domain($url){

    $pattern = "/[w-] .(com|net|org|gov|cc|biz|info|cn)(.(cn|hk))*/";

    preg_match($pattern, $url, $matches);

    if(count($matches) > 0) {

    return $matches[0];

    }else{

    $rs = parse_url($url);

     

    $main_url = $rs["host"];

 

    if(!strcmp(long2ip(sprintf("%u",ip2long($main_url))),$main_url)) {

    return $main_url;

    }else{

    $arr = explode(".",$main_url);

    $count=count($arr);

    $endArr = array("com","net","org","3322");//com.cn net.cn 等情况

    if (in_array($arr[$count-2],$endArr)){

        if(isset($arr[$count-4])){

            $domain = "http://".$arr[$count-4].".".$arr[$count-3].".".$arr[$count-2].".".$arr[$count-1];

        }else{

            $domain = $arr[$count-3].".".$arr[$count-2].".".$arr[$count-1];

        }

    }else{

        if(isset($arr[$count-3])){

            $domain = "http://".$arr[$count-3].".".$arr[$count-2].".".$arr[$count-1];

        }else{

            $domain = "http://".$arr[$count-2].".".$arr[$count-1];

        }

     

    }

    return $domain;

    }// end if(!strcmp...)

    }// end if(count...)

    }// end function

echo get_domain("http://blog.csd.com.hk")."<br>";

echo get_domain("http://www.csd.net/www")."<br>";

echo get_domain("http://csd.net/")."<br>";

echo get_domain("http://csd.net/fdfdfd")."<br>";