Rails default middleware

middleware.rb

#!/usr/bin/env ruby
# http://guides.rubyonrails.org/v3.2.8/rails_on_rack.html
require 'rack'
require 'rails/all'

# Defaults are defined in railties/lib/rails/application/default_middleware_stack.rb
class Application < Rails::Application
  routes.draw do
    root to: Proc.new { [200, {'Content-Type' => 'text/html'}, ["Hello from app"]] }
  end

  configure do
    # if config.force_ssl
    middleware.use ActionDispatch::SSL
    middleware.use Rack::Sendfile
    # if config.public_file_server.enabled
    middleware.use ActionDispatch::Static
    # if config.action_dispatch.rack_cache
    # require "action_dispatch/http/rack_cache"
    # middleware.use ::Rack::Cache, rack_cache
    # if config.allow_concurrency == false
    middleware.use Rack::Lock
    # middleware.use ::ActionDispatch::Executor, app.executor
    middleware.use ::Rack::Runtime
    # if config.api_only == false
    # middleware.use ::Rack::MethodOverride
    middleware.use ActionDispatch::RequestId
    middleware.use Rails::Rack::Logger
    middleware.use ActionDispatch::ShowExceptions
    middleware.use ActionDispatch::DebugExceptions
    middleware.use ActionDispatch::RemoteIp
    # if config.cache_classes == false
    # middleware.use ActionDispatch::Reloader, app.reloader
    middleware.use ActionDispatch::Callbacks
    # if config.api_only == false
    middleware.use ::ActionDispatch::Cookies
    # if config.api_only == false and config.session_store
    # middleware.use config.session_store, config.session_options
    # middleware.use ::ActionDispatch::Flash
    # middleware.use ActionDispatch::Head
    middleware.use Rack::ConditionalGet
    middleware.use Rack::ETag, "no-cache"
  end
end

Rack::Handler::WEBrick.run Application.routes