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If you have a form, you sometimes need special validation Rules not included in Yii. Here i share a special rule with you, i just wrote. Maybe you have the case, when a user needs to Fill ou Field A oder the Fields B, C and D.
This wiki shows how to get the geolocation info of the client using another server API
It could be write also as extension but there are a lots of APIs that change the below code
So, I wrote the below code that works for one of them (using www.geoplugin.net)
Once you have installed and configured the rights extension in your application, you can change the table name from 'User' to any table name you want and similarly for 'username' column to any other column name.