What is the best way to implement the work of the site for different cities?

Question

PHP

Hello!
There is a task to make one site on subdomains for each city. That is, there is a subdomain, for example, nn.site.ru - this is a site for Nizhny Novgorod, all content is shown for Nizhny Novgorod. Similarly, there is a subdomain kazan.site.ru, for it information for the city of Kazan.
What is the best way to determine the city in which a person is located and redirect him to the desired domain? It is also possible to choose a city on your own, as, for example, is done on avito.
Perhaps there are ready-made solutions?
Site running Joomla 3.

Answer 1

There are libraries that determine the city of the visitor, insert this city into cookies and display the necessary information
https://sypexgeo.net/

Answer 2

I recently made such an order for 80 cities based on one OpenCart.