Ruby: Destructors?

Question

I need to occasionaly create images with rmagick in a cache dir.

To then get rid of them fast, without loosing them for the view, I want to delete the image-files wh

Answer 1

There is very simple solution for your problem. Ruby design encourage you to do all actions in definite and clear way. No need for magic actions in constructor/destructor. Yes, constructors are required as a convenient way to assign initial state of object but not for "magic" actions. Let me illustrate this approach on possible solution. Goal, to keep image objects available but clean cache files of images.

# you are welcome to keep an in memory copy of the image
# GC will take care of it.
class MyImage
  RawPNG data
end

# this is a worker that does operations on the file in cache directory.
# It knows presizely when the file can be removed (generate_image_final)
# no need to wait for destructor ;)
class MyImageGenerator
  MyImage @img

  def generate_image_step1
    @image_file = ImageLib.create_file
  end
  def generate_image_step2
    ImageLib.draw @image_file
  end
  def generate_image_final
    @img=ImageLib.load_image @image_file
    delete_that_file @image_file
  end

  def getImage
    # optional check image was generated
    return @img
  end
end