ActionController::Metal is the simplest possible controller,
providing a valid Rack interface without the
additional niceties provided by ActionController::Base.
A sample metal controller might look like this:
class HelloController < ActionController::Metal
def index
self.response_body = "Hello World!"
end
end
And then to route requests to your metal controller, you would add
something like this to config/routes.rb:
get 'hello', to: HelloController.action(:index)
The action method returns a valid Rack application for the Rails router to dispatch
to.
Rendering Helpers
ActionController::Metal by default provides no utilities for
rendering views, partials, or other responses aside from explicitly calling
of response_body=, content_type=, and
status=. To add the render helpers you're used to having
in a normal controller, you can do the following:
class HelloController < ActionController::Metal
include AbstractController::Rendering
include ActionView::Layouts
append_view_path "#{Rails.root}/app/views"
def index
render "hello/index"
end
end
Redirection Helpers
To add redirection helpers to your metal controller, do the following:
class HelloController < ActionController::Metal
include ActionController::Redirecting
include Rails.application.routes.url_helpers
def index
redirect_to root_url
end
end
Other Helpers
You can refer to the modules included in
ActionController::Base to see other features you can bring
into your metal controller.