    # File lib/action_controller/vendor/rack-1.0/rack/request.rb, line 221
        def accept_encoding
          @env["HTTP_ACCEPT_ENCODING"].to_s.split(/,\s*/).map do |part|
            m = /^([^\s,]+?)(?:;\s*q=(\d+(?:\.\d+)?))?$/.match(part) # From WEBrick

            if m
              [m[1], (m[2] || 1.0).to_f]
            else
              raise "Invalid value for Accept-Encoding: #{part.inspect}"
            end
          end
        end