A simple, custom Rails middleware class

service_worker_manager.rb

# app/middleware/service_worker_manager.rb

class ServiceWorkerManager
  # We’ll pass 'service_workers' when we register this middleware.
  def initialize(app, service_workers)
      @app = app
      @service_workers = service_workers
  end
  
  def call(env)
    # Let the next middleware classes & app do their thing first…
    status, headers, response = @app.call(env)
    dont_cache = @service_workers.any? { |worker_name| env['REQUEST_PATH'].include?(worker_name) }
  
    # …and modify the response if a service worker was fetched.
    if dont_cache
      headers['Cache-Control'] = 'no-cache'
    end
    [status, headers, response]
  end
end