Compressed fields in Mongoid 6.4

compressed.rb

require 'zlib'

class CompressedString < String
  def mongoize
    BSON::Binary.new(Zlib::Deflate.deflate(self))
  end

  class << self
    # Get the object as it was stored in the database, and instantiate
    # this custom class from it.
    def demongoize(object)
      case object
      when BSON::Binary then CompressedString.new(Zlib::Inflate.inflate(object.data))
      when String then CompressedString.new(object)
      else object
      end
    end

    # Takes any possible object and converts it to how it would be
    # stored in the database.
    def mongoize(object)
      case object
      when CompressedString then object.mongoize
      when String then CompressedString.new(object).mongoize
      else object
      end
    end

    # Converts the object that was supplied to a criteria and converts it
    # into a database friendly form.
    alias_method :evolve, :mongoize
  end
end