Make blank params[] nil

Question

When a user submits a form and leaves certain fields blank, they get saved as blank in the DB. I would like to iterate through the params[:user] collection (for example) an

Answer 1

before_save seems like the wrong location to me, what if you want to use the value before saving. So I overrode the setters instead:

# include through module or define under active_record
def self.nil_if_blank(*args)
  args.each do |att|
    define_method att.to_s + '=' do |val|
      val = nil if val.respond_to?(:empty?) && val.empty?
      super(val)
    end
  end
end

#inside model
nil_if_blank :attr1, :attr2

---

Just to be complete I put the following in lib/my_model_extensions.rb

module MyModelExtensions
  def self.included(base)
    base.class_eval do
      def self.nil_if_blank(*args)
        args.each do |att|
          define_method att.to_s + '=' do |val|
            val = nil if val.respond_to?(:empty?) && val.empty?
            super(val)
          end
        end
      end
    end
  end
end

and use it like this:

class MyModel
  include MyModelExtensions
  nil_if_blank :attr1, :attr2
end