Support `relative_url_root`

[andyundso]

Feature Request

Is your feature request related to a problem?

yes and no. we have a Rails application which can run under a relative root url, configured with ActionController::Base.config.relative_url_root. what we noted is:

• the reflex is sent with the full path, including the value configured in config.relative_url_root.
• StimulusReflex is then unable to resolve the corresponding controller and action.

we had to adjust config.ru to make the relative root url work (prior to adding StimulusReflex)

# This file is used by Rack-based servers to start the application.

require_relative "config/environment"

map ActionController::Base.config.relative_url_root || "/" do
  run Rails.application
end

Rails.application.load_server

currently we use a small monkey-patch to make it work with StimulusReflex.

class StimulusReflex::ReflexData
  def url
    url = data[:url].to_s

    if ActionController::Base.config.relative_url_root
      url.gsub(ActionController::Base.config.relative_url_root, "")
    else
      url
    end
  end
end

Describe the solution you'd like

would be nice if relative_root_url is considered by StimulusReflex.

Additional context

nothing really to add

PR link

happy to send a PR if the monkey-patch is good enough :)