Rails call same action code from two controllers (with a small difference)

I have two different routes that need to output the same page with only minor differences (title, open graph tags, etc.)

routes.rb

match 'referral/:ref' => 'referral#home'
root :to => "home#index"

I'm not willing to copy the exact same code from the HomeController to the ReferralController and I don't want a redirect, because the title and OG tags must be different (in order to have a special referral title when the page is shared)

With an express.js app (which I'm more familiar with), I would add a middleware in the referral route and then call the HomeController#index action. So everything would be done at the routing level.

What's the idiomatic approach in Rails?

Thanks, Laurent