class Rack::Auth::AbstractRequest

def authorization_key
  @authorization_key ||= AUTHORIZATION_KEYS.detect { |key| @env.has_key?(key) }
end

def initialize(env)
  @env = env
end

def params
  @params ||= parts.last
end

def parts
  @parts ||= @env[authorization_key].split(' ', 2)
end

def provided?
  !authorization_key.nil? && valid?
end

def request
  @request ||= Request.new(@env)
end

def scheme
  @scheme ||= parts.first&.downcase
end

def valid?
  !@env[authorization_key].nil?
end