Question

I have a Model like this:

class MyModel
  attr_accessor :size
end

Now i want to display the size in a human readable format. I could do this by adding the following code:

class MyModel

  attr_accessor :size

  def size_hr(bytes = nil, counter = -1)
    counter += 1
    bytes ||= size
    if bytes < 1024
      return "#{bytes.round(2)} #{unit_for(counter)}"
    else
      size_hr bytes/1024, counter
    end
  end

  def unit_for(counter)
    case counter
    when 0 then "B"
    when 1 then "KiB"
    when 2 then "MiB"
    when 3 then "GiB"
    end
  end
end

But I feel somehow bad about this as I would mix view stuff into the model. I’m looking for a design pattern which would be the right approach to do this. I read about decorator and presenter, but I don’t think they fit in here. What would be the right approach for this?

Answer 1

You can use Rails View Helpers, which is the simple and straight forward way. IMHO the Helpers tend to end up as junk drawer for all sorts of things. Thus, we prefer do work with the Deocrator Pattern. A good gem to do this would be draper.