# File lib/chef/rest.rb, line 326
    def authentication_headers(method, url, json_body=nil)
      request_params = {:http_method => method, :path => url.path, :body => json_body, :host => "#{url.host}:#{url.port}"}
      request_params[:body] ||= ""
      auth_credentials.signature_headers(request_params)
    end