如何使用api获取城市名称

Below url is the api for getting the api for getting city and country name using the ip. But i have used the different parameters like json

$json = file_get_contents(" http://api.ipinfodb.com/v3/ip-city/?key=a2f2062d64fd705bbb32ce4c44e8ebb508d080990528d7cb4f1a0c5e7ddf5c1e&ip=".$ip."&format=json"); 
$json = json_decode($json,true); 
$city=$json['CityName'];

example url below for ip

 http://api.ipinfodb.com/v3/ip-city/?key=a2f2062d64fd705bbb32ce4c44e8ebb508d080990528d7cb4f1a0c5e7ddf5c1e&ip=74.125.45.100&format=json

The c in cityName is lowercase.

$city = $json['cityName'];