Elasticsearch in RoR. Get rid of the 3rd level domain. How to correctly specify paths in routes?

Question

Ruby on Rails

In general, everything is fine for the 2nd level domain. - example.com/search?utf8=✓&query=example1
The 3rd level domain requires that the query redirect to the 2nd level domain and not stay on the 3rd level domain. - foo.example.com/search?utf8=✓&query=example2
And more, how and is it worth getting rid of the parameter in the utf8=✓ request? Because I know that it is kind of like for IE old versions.
using kaminari

Answer 1

For all subdomains

Rails.application.routes.draw do
  constraints subdomain: /.+/ do
    get '/(*uri)' => redirect { |params, request| "http://example.com#{request.original_fullpath}" }
  end

  root 'welcome#index'
end

For specific constraints subdomain: 'foo'
In general, maybe it makes sense to configure this in nginx?