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middleware_insertion_points

🛠️ Insert Middleware at Specific Points​

Rails lets you precisely position middleware relative to built‑in components using insert_before and insert_after. This is especially useful when you depend on data set up by another middleware or need to wrap its behavior.

# config/application.rb
module MyApp
  class Application < Rails::Application
    # Run custom auth check before Rack::Runtime sets X-Runtime
    config.middleware.insert_before Rack::Runtime, AuthCheckMiddleware

    # Or run a response sanitizer after ActionDispatch::Static serves files
    config.middleware.insert_after ActionDispatch::Static, ResponseSanitizer
  end
end

The order you inject matters: use insert_before to run yours earlier, and insert_after to wrap on the way out.