Question

This means app-name.heroku.com.

Note this is different from Rails.application.class.parent_name.

Rails.application.class.parent_name is defined in the application.

Working in Rails 3.

Answer 1

Heroku actually sets a URL variable in the environment by default

app_name = ENV['URL'].split(".").first

Referenced here: http://devcenter.heroku.com/articles/config-vars and http://ididitmyway.heroku.com/past/2010/11/9/sinatra_settings_and_configuration/

update: actually the URL variable might not be there by default, but you could always add an environment variable “app name” a priori, unless you were trying to avoid that approach all together.

update 2: indeed, the other, obvious but limiting approach, would be to grab the domain off the request variable, but this limits you to your controller. http://guides.rubyonrails.org/action_controller_overview.html#the-request-object