Question

I have an event table that contains start_at and ends_at. It also have a boolean for allday.

If the event is allday, then the user enters a field called hours. But, if they enter the start_at and ends_at, I’ld like to calculate and save in the hours field.

In English (not Ruby):

If event.allday = > true
  hours = ends_at - starts_at

This way, I wouldn’t have to calculate it during all the different display pages I have and it would be easier to sum.

OR – would this logic go into the model?

Thanks!

UPDATE———–

I tried putting this into the model:

  before_save :calculate_hours

  def calculate_hours
    if self.allday != true
      self.hours = ((self.ends_at - self.starts_at)/ 3600).to_f.round(2)
    end
 end

Answer 1

Business logic always belongs in the model.

class Event < ActiveRecord::Base
  before_validation :set_hours

  private
    def set_hours
      if allday?
        self.hours = ends_at - starts_at
      end
    end
end