php获取当前域名与url地址的例子

/**
* 获得网站的URL地址
*
* @return string
*/
function site_url()
{
return get_domain() . substr(PHP_SELF, 0, strrpos(PHP_SELF, '/'));
}

/**
* 获得当前的域名
*
* @return string
*/
function get_domain()
{
/* 协议 */
$protocol = (isset($_SERVER['HTTPS']) && (strtolower($_SERVER['HTTPS']) != 'off')) ? 'https://' : 'http://';

/* 域名或IP地址 */
if (isset($_SERVER['HTTP_X_FORWARDED_HOST']))
{
$host = $_SERVER['HTTP_X_FORWARDED_HOST'];
}
elseif (isset($_SERVER['HTTP_HOST']))
{
$host = $_SERVER['HTTP_HOST'];
}
else
{
/* 端口 */
if (isset($_SERVER['SERVER_PORT']))
{
$port = ':' . $_SERVER['SERVER_PORT'];

if ((':80' == $port && 'http://' == $protocol) || (':443' == $port && 'https://' == $protocol))
{
$port = '';
}
}
else
{
$port = '';
}

if (isset($_SERVER['SERVER_NAME']))
{
$host = $_SERVER['SERVER_NAME'] . $port;
}
elseif (isset($_SERVER['SERVER_ADDR']))
{
$host = $_SERVER['SERVER_ADDR'] . $port;
}
}
return $protocol . $host;
}