在 PHP 中通过 IP 地址获取城市国家

如何在 PHP 中通过 IP 地址获取城市国家？代码如下：

<?php /*Get user ip address*/
$ip_address=$_SERVER['REMOTE_ADDR'];
/*Get user ip address details with geoplugin.net*/
$geopluginURL='http://www.geoplugin.net/php.gp?ip='.$ip_address;
$addrDetailsArr = unserialize(file_get_contents($geopluginURL));
/*Get City name by return array*/
$city = $addrDetailsArr['geoplugin_city'];
/*Get Country name by return array*/
$country = $addrDetailsArr['geoplugin_countryName'];
/*Comment out these line to see all the posible details*/
/*echo '<pre>';
print_r($addrDetailsArr);
die();*/
if(!$city){
   $city='Not Define';
}if(!$country){
   $country='Not Define';
}
echo '<strong>IP Address</strong>:- '.$ip_address.'<br/>';
echo '<strong>City</strong>:- '.$city.'<br/>';
echo '<strong>Country</strong>:- '.$country.'<br/>';
?>