Refactor a view by a decorator, a presenter, an helper or something else?

Rails
1

Hi,

In a view, I have this code :

<% MeasureUnitDecorator.all.each do |mu| %>
  <p>
    <b>Dimensions in <%= mu.title %> :</b> <%=

painting.convert(:width,
mu) %> x <%= painting.convert(:height, mu) %>
<% if painting.depth %>
x <%= painting.convert(:depth, mu) %>
<% end %>


<% end %>

<% MeasureUnitDecorator.all.each do |mu| %>
  <p>
    <b>Dimensions with frame in <%= mu.title %> :</b> <%=

painting.convert(:width_with_frame, mu) %> x <%=
painting.convert(:height_with_frame, mu) %>
<% if painting.depth %>
x <%= painting.convert(:depth_with_frame, mu) %>
<% end %>


<% end %>

The result is this this :

<p><b>Dimensions in cm :</b> 10 x 14 x 16</p>
<p><b>Dimensions with frame in cm :</b> 12 x 16 x 18</p>

It work but I think there is too many logic in a view and I have a lot
of
duplications.

I tried to refactor this code with a decorator like this (in this view :
) :

<% MeasureUnitDecorator.all.each do |mu| %>
  <%= painting.dimensions_in(mu) %>
<% end %>

And in a decorator :

#....
def dimensions_in(mu)
  properties = [:width, :height, :depth]
  dimensions = formated_dimensions(properties)
  h.content_tag(:p, "<b>Dimensions in #{mu.title} :</b>

#{dimensions}".html_safe)
end

def dimensions_with_frame_in(mu)
  properties = [:width_with_frame, :height_with_frame,

:depth_with_frame]
dimensions = formated_dimensions(properties)
h.content_tag(:p, “Dimensions with frame in #{mu.title} :
#{dimensions}”.html_safe)
end

private
def formated_dimensions(properties)
  properties.map { |p| convert(p, mu) }.compact.join(" x ")
end

def convert(property, unit)
  source_unit = model.measure_unit.title
  target_unit = unit.title.to_sym
  depth.send(source_unit).convert(target_unit).to_f.round(2)
end
#....

It’s cleaner but I think the decorator have too many responsabilities so
I
did this (in a presenter file) :

class DimensionPresenter
  attr_accessor :painting, :measure_unit, :source_unit, :target_unit

  def initialize(painting, measure_unit)
    @painting = painting
    @measure_unit = measure_unit
  end

  def format(properties)
    properties.map { |p| convert(p, mu) }.compact.join(" x ")
  end

  def source_unit
    @source_unit ||= painting.measure_unit.title
  end

  def target_unit
    @target_unit ||= measure_unit.unit.title.to_sym
  end

  def convert(property, unit)
    depth.send(source_unit).convert(target_unit).to_f.round(2)
  end
end

And I use it in my decorator like this :

def dimensions_in(mu)
  properties = [:width, :height, :depth]
  formated_dimensions = DimensionPresenter.new(painting,

mu).format(properties)
h.content_tag(:p, “Dimensions in #{mu.title} :
#{dimensions}”.html_safe)
end

def dimensions_with_frame_in(mu)
  properties = [:width_with_frame, :height_with_frame,

:depth_with_frame]
formated_dimensions = DimensionPresenter.new(painting,
mu).format(properties)
h.content_tag(:p, “Dimensions with frame in #{mu.title} :
#{dimensions}”.html_safe)
end

It’s ok but I don’t like to pass a model as argument in a decorator
function. A decorator function should use only the decorated model.

I can also use a presenter like this :

<% MeasureUnitDecorator.all.each do |mu| %>
  <%= DimensionPresenter.new(painting, mu).format %>
<% end %>

<% MeasureUnitDecorator.all.each do |mu| %>
  <%= DimensionPresenter.new(painting, mu).format_with_frame %>
<% end %>

But I don’t like to initialize an object in a view. I can also create an
instance variable in the controller but I don’t want to pass many
instance
variable. It’s not in the Sandy Metz best practices (

).

I also think to an helper by I think an help method but be generic and
should can be used by every models. This is not the case for this
because
the is only a painting with this attributes.

So… I don’t know what to do. It’s a very little thing but I don’t find
the solution.

What do you think? Do you have a better solution?

Thanks!