OmniContacts Rails

Question

Task: import contacts from Gmail.

I use gem omnicontacts.

omnicontacts.rb:

Rails.application.middleware.use OmniContacts::Builder do
  importer :gmail, ENV['API_KEY'], ENV['API_SECRET'], {:redirect_path => '/contacts/gmail/callback'}

My controller:

def callback
    provider = params[:importer]
    @contacts = request.env['omnicontacts.contacts']
    @user = request.env['omnicontacts.user']
    if @contacts.nil?
      session[:message] = {
          :text => "Sorry, we didn't find any of your friends at this time. Please try again later.",
          :type => 'notice'
      }
    else
    ...
end

My routes.rb:

get '/contacts/:importer'  => 'contacts_importer#callback', as: :import_contacts
get '/contacts/:importer/callback' => 'contacts_importer#callback'
get '/contacts/failure' => 'contacts_importer#failure'

I do everything as indicated in the documentation https://github.com/Diego81/omnicontacts

But @contacts and @user is always nil.

Why?