server.rb

    def serialize(key, value, options=nil)
      marshalled = false
      value = unless options && options[:raw]
        marshalled = true
        begin
          Marshal.dump(value)
        rescue => ex
          # Marshalling can throw several different types of generic Ruby exceptions.
          # Convert to a specific exception so we can special case it higher up the stack.
          exc = Dalli::MarshalError.new(ex.message)
          exc.set_backtrace ex.backtrace
          raise exc
        end
      else
        value.to_s
      end
      compressed = false
      if @options[:compression] && value.bytesize >= COMPRESSION_MIN_SIZE
        value = Zlib::Deflate.deflate(value)
        compressed = true
      end
      raise Dalli::DalliError, "Value too large, memcached can only store #{@options[:value_max_bytes]} bytes per key [key: #{key}, size: #{value.bytesize}]" if value.bytesize > @options[:value_max_bytes]
      flags = 0
      flags |= FLAG_COMPRESSED if compressed
      flags |= FLAG_MARSHALLED if marshalled
      [value, flags]
    end