如何在 Rails 6 中使用rescue_from？

Question

Apparently rescue_from is supposed to catch Exceptions, but this does not work as expected:

class ApplicationController < ActionController::Base
  rescue_from ActionController::RoutingError, with: :not_found

  def not_found
    text: 'Not found'
  end
end

Spec:

specify 'Not found' do
  visit '/zzz'
  expect(page.status_code).to eq 200
end

Failure/Error: visit '/zzz'

     ActionController::RoutingError:
       No route matches [GET] "/zzz"

Same behavior in development environment.

However, rescuing other errors such as RuntimeError does work as expected.

Docs: https://apidock.com/rails/v6.0.0/ActiveSupport/Rescuable/ClassMethods/rescue_from

Rails 6.0.2

Why can't RoutingError be used with rescue_from ? Is RoutingError raised in middleware or by the router before the controller is called? Is there another way to catch RoutingError ?

Answer 1

Router errors are raised before reaching a controller, you could have a wildcard route to match anything that's not matched by other routes at the end of the routes.rb file an point that route to a specific controller action.

Something like:

match '*foo', to: 'application#not_found'

(Didn't try that, you may need to tweak it a little but I think the idea is clear)