lulalala

class Banner < ActiveRecord::Base
  attr_accessor :image_width, :image_height
  mount_uploader :image, ImageUploader
  
  validate :check_dimensions, :on => :create
  def check_dimensions
    if !image_cache.nil? && (image.width < 300 || image.height < 300)
      errors.add :image, "Dimension too small."
    end
  end

lulalala

#
# At CoverHound, we use conditional validations all over the form. However, there is no proper way to do
# this in Rails. Instead, we can provide an array of attributes (validated_fields attribute)
# and ensure they are the only ones to get validated.
#

module ConditionalValidations
  attr_accessor :validated_fields

  def field_is_required?(field)