class Grape::Request

def build_headers
  Grape::Util::Lazy::Object.new do
    env.each_pair.with_object(Grape::Util::Header.new) do |(k, v), headers|
      next unless k.to_s.start_with? HTTP_PREFIX
      transformed_header = Grape::Http::Headers::HTTP_HEADERS[k] || transform_header(k)
      headers[transformed_header] = v
    end
  end
end

def grape_routing_args
  args = env[Grape::Env::GRAPE_ROUTING_ARGS].dup
  # preserve version from query string parameters
  args.delete(:version)
  args.delete(:route_info)
  args
end

def headers
  @headers ||= build_headers
end

def initialize(env, build_params_with: nil)
  extend build_params_with || Grape.config.param_builder
  super(env)
end

def params
  @params ||= build_params
rescue EOFError
  raise Grape::Exceptions::EmptyMessageBody.new(content_type)
rescue Rack::Multipart::MultipartPartLimitError
  raise Grape::Exceptions::TooManyMultipartFiles.new(Rack::Utils.multipart_part_limit)
end

def transform_header(header)
  -header[5..].tr('_', '-').downcase
end