How to get the subdomain value from a url?

Question

how can I get the subdomain value in rails, is there a built-in way to do this?

e.g.

test123.example.com

I want the test123 part of

Answer 1

In case you are working with a string, and assuming it can be a true URI, you can do this to extract the subdomain.

require 'uri'

uri = URI.parse('http://test123.example.com')
uri.host.split('.').first
=> "test123"

https://stackoverflow.com/a/13243810/3407381