# File lib/selenium/webdriver/remote/http/common.rb, line 21
          def call(verb, url, command_hash)
            url      = server_url.merge(url) unless url.kind_of?(URI)
            headers  = DEFAULT_HEADERS.dup
            headers['Cache-Control'] = "no-cache" if verb == :get

            if command_hash
              payload                   = WebDriver.json_dump(command_hash)
              headers["Content-Type"]   = "#{CONTENT_TYPE}; charset=utf-8"
              headers["Content-Length"] = payload.bytesize.to_s if [:post, :put].include?(verb)

              if $DEBUG
                puts "   >>> #{url} | #{payload}"
                puts "     > #{headers.inspect}"
              end
            elsif verb == :post
              payload = "{}" # work around http://code.google.com/p/selenium/issues/detail?id=1396
              headers["Content-Length"] = "2"
            end

            request verb, url, headers, payload
          end