?? 意思是，判断前面的值是否存在，存在则使用前面的值，不存在，则使用??后面的值。两个问好之间不可以有空格
$res = isset($_GET['name']) ?$_GET['name']: 'long';
$res = $_GET['name'] ?? 'long';
/**
* Get client ip.
*
* @return string
*/
function get_client_ip()
{
if (!empty($_SERVER['REMOTE_ADDR'])) {
$ip = $_SERVER['REMOTE_ADDR'];
} else {
// for php-cli(phpunit etc.)
$ip = defined('PHPUNIT_RUNNING') ? '127.0.0.1' : gethostbyname(gethostname());
}
return filter_var($ip, FILTER_VALIDATE_IP) ?: '127.0.0.1';
}
/**
* Get current server ip.
*
* @return string
*/
function get_server_ip()
{
if (!empty($_SERVER['SERVER_ADDR'])) {
$ip = $_SERVER['SERVER_ADDR'];
} elseif (!empty($_SERVER['SERVER_NAME'])) {
$ip = gethostbyname($_SERVER['SERVER_NAME']);
} else {
// for php-cli(phpunit etc.)
$ip = defined('PHPUNIT_RUNNING') ? '127.0.0.1' : gethostbyname(gethostname());
}
return filter_var($ip, FILTER_VALIDATE_IP) ?: '127.0.0.1';
}
/**
* Return current url.
*
* @return string
*/
function current_url()
{
$protocol = 'http://';
if (!empty($_SERVER['HTTPS']) || ($_SERVER['HTTP_X_FORWARDED_PROTO'] ?? 'http') === 'https') {
$protocol = 'https://';
}
return $protocol.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
}
