Callback object problem

Rails
1

I’m trying to create a separate class to do validation so that about 10
models can use the same date validation. I have tried to use the
example from the agile book but it’s not working. Here’s what I have:

app/models/date_callbacks.rb
class DateCallbacks

def before_validation(model)
	if model.start_date > Date.today
		model.errors.add(:start_date, "must be before today")
	end
	if !model.end_date.nil?
		if model.end_date > Date.today
			model.errors.add(:end_date, "must be before today")
		end
   end
	if !model.end_date.nil?
		if model.end_date < model.start_date
			model.errors.add(:end_date, "must be later than start date")
		end
	end
end

end

app/models/address_history.rb
class PostgradTraining < ActiveRecord::Base
before_validation DateCallbacks.new
…
end

the error i get is:
Callbacks must be a symbol denoting the method to call, a string to be
evaluated, a block to be invoked, or an object responding to the
callback method.

thanks for any help,

Nate

2

I’m sorry to bump this; but, i am still having trouble with it.