class Rack::Defaults
  def initialize(app, **options)
    @app = app
    @options = options
  end

  attr :options

  def call(env)
    env.merge!(@options)
    @app.call(env)
  end
end

And:

• Documentation/standards for all the currently "global configurations" that we have.
• Changes to code to use these configuration values where possible.

Notable Cases

• Multipart parser / configuration.
• Query string parser / configuration.
• Handling of IP addresses and forwarded headers.
• ... please edit and add more ...