# File lib/rack/request.rb, line 226
    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