PHP 获取顶级域名 获取域名的函数 parseHost()

2012-12-19补充：

1）最新的更新版在 http://blog.youkuaiyun.com/default7/article/details/8332612

2）第7行代码那个empty多显示了，可以直接点击看源码。

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写了一个测试了一下，很不错！

  function parseHost($httpurl)
  {
    $httpurl = strtolower( trim($httpurl) );
    if(empty($httpurl)) return ;
    $regx1 = '/https?:\/\/(([^\/\?#]+\.)?([^\/\?#-\.]+\.)(com\.cn|org\.cn|net\.cn|com\.jp|co\.jp|com\.kr|com\.tw)(\:[0-9]+)?)/i';
    $regx2 = '/https?:\/\/(([^\/\?#]+\.)?([^\/\?#-\.]+\.)(cn|com|org|net|cc|biz|hk|jp|kr|name|me|tw|la)(\:[0-9]+)?)/i';
    $host = $tophost = '';
    if(preg_match($regx1,$httpurl,$matches))
    {
      $host = $matches[1];
    } elseif(preg_match($regx2, $httpurl, $matches)) {
      $host = $matches[1];
    }
    if($matches) $tophost = $matches[2] == 'www.' ? $host:$matches[3].$matches[4].$matches[5];
    return array($host,$tophost);
  }

测试代码：

//test
$arr=array(
'http://www.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!',
'http://www.a.b.c.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!',
'http://www.a.b.c.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!',
'http://www.baidu.com/#asdfasdfasd',
'www.baidu.com',
'baidu',
'http://a.b.c.d.com.cn:3306/asdfasdfadsfasd.asp?3adf=&adsfa#dead!dfadf^gadgad',
);
echo "<pre>";
foreach ($arr as &$value) {
  echo $value."\n";
  print_r( parseHost($value));
  echo "\n\n";
}
echo "</pre>";

输出如下：

http://www.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!
Array
(
    [0] => www.baidu.com.cn:8080
    [1] => www.baidu.com.cn:8080
)


http://www.a.b.c.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!
Array
(
    [0] => www.a.b.c.baidu.com.cn:8080
    [1] => baidu.com.cn:8080
)


http://www.a.b.c.baidu.com.cn:8080/ABCDEFGH.PHP?A=1&B=2#0000!
Array
(
    [0] => www.a.b.c.baidu.com.cn:8080
    [1] => baidu.com.cn:8080
)


http://www.baidu.com/#asdfasdfasd
Array
(
    [0] => www.baidu.com
    [1] => www.baidu.com
)


www.baidu.com
Array
(
    [0] => 
    [1] => 
)


baidu
Array
(
    [0] => 
    [1] => 
)


http://a.b.c.d.com.cn:3306/asdfasdfadsfasd.asp?3adf=&adsfa#dead!dfadf^gadgad
Array
(
    [0] => a.b.c.d.com.cn:3306
    [1] => d.com.cn:3306
)