Swap RAILS middleware before initialized

Question

Let's say this is my RAILS middleware stack after the app is completely booted up:

> Rails.application.middleware

#<ActionDispatch::MiddlewareStack:0x007f9d1636e970
 @middlewares=
  [FooMiddleware,
   ...
   ...
   ...
   SomeEngine::SomeMiddleware]>

Before the initialization process finishes and the middleware stack is frozen, I need to swap SomeEngine::SomeMiddleware with MyProxyMiddleware.

How do you delay inserting or swapping a middleware until all other initializations have been completed, from both the application and the engines it incorporates?

I can't find a place to hook into where the middleware stack is unfrozen but all SomeEngine has been initialized.

If it matters, this is on RAILS 4.2.

Thanks!

Answer 1

Figured it out:

# config/application.rb

module MyApplication
  class Application < Rails::Application
    # ...

    initializer :foo do |app|
      app.middleware.swap SomeEngine::SomeMiddleware, BarMiddleware
    end
  end
end

Hope this helps other people. Cheers.