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

A bit late to the party but here's what I used in older versions of rails.

subdomain = request.subdomains.join('.')

It should be backwards compatible in newer versions