PHP获取当前页面的完整url地址

function get_url()
    {
        $sys_protocal = isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == '443' ? 'https://' : 'http://';
        $php_self = $_SERVER['PHP_SELF'] ? $_SERVER['PHP_SELF'] : $_SERVER['SCRIPT_NAME'];
        $path_info = isset($_SERVER['PATH_INFO']) ? $_SERVER['PATH_INFO'] : '';
        $relate_url = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : $php_self . (isset($_SERVER['QUERY_STRING']) ? '?' . $_SERVER['QUERY_STRING'] : $path_info);
        return $sys_protocal . (isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : '') . $relate_url;
    }