You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: action_controller_request.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/oauth-0.5.3/lib/oauth/request_proxy
    
    the code of the file until where you have to start completion: require 'active_support'
require "active_support/version"
require 'action_controller'
require 'uri'

if
  Gem::Version.new(ActiveSupport::VERSION::STRING) < Gem::Version.new("3")
then # rails 2.x
  requ
    
    def parameters_for_signature
      params = []
      params << options[:parameters].to_query if options[:parameters]

      unless options[:clobber_request]
        params << header_params.to_query
        params << request.query_string unless query_string_blank?

        if request.post? && request.content_type.to_s.downcase.start_with?("application/x-www-form-urlencoded")
          params << request.raw_post
        end