Persisted users across vendors

If you would like the current_spree_user to persist across subdomains, change this line in config/initializers/session_store.rb:

 Rails.application.config.session_store :cookie_store, key: '_your_app_session', domain: :all, tld_length: 2

Furthermore, to persist the cart across subdomains and to add items smoothly, there is a little more work you have to do. The cart/checkout does accept multiple vendor items at once out of the box, but you will encounter problems of it a) not persisting the cart across subdomains correctly and b) raising an error once you do persist it correctly.

To overcome the first problem, you need to override the default behavior for setting the guest_token. Create a file under app/helpers/spree/auth_decorator.rb:

Spree::Core::ControllerHelpers::Auth.class_eval do
  def set_guest_token
    unless cookies.signed[:guest_token].present?
      cookies.permanent.signed[:guest_token] = {
        value: SecureRandom.urlsafe_base64(nil, false),
        domain: :all,
        tld_length: 2
      }
    end
  end
end

This change makes it so all the domains are under the same guest_token cookies, instead of having unique guest_token cookies for each.

The second change requires patching how the order params are set in order.rb. Under app/helpers/spree/order_decorator.rb, patch it with the following:

Spree::Core::ControllerHelpers::Order.class_eval do
  def current_order_params
    { currency: current_currency, guest_token: cookies.signed[:guest_token], user_id: try_spree_current_user.try(:id) }
  end
end

This change prevents the cart from only including items specific to a subdomain/store. You will also need to comment out

raise ProductDoesNotBelongToStoreError if order.store.present? && !product.stores.include?(order.store)

in app/models/spree_multi_domain/line_item_concerns.rb in order to add items without raising this error.