Rails 3 - Custom Validation

Question

I\'m somewhat confused by my options for custom validations in Rails 3, and i\'m hoping that someone can point me in the direction of a resource that can help with my current is

Answer 1

You can use the ActiveModel::Validator class like so:

class VehicleValidator < ActiveModel::Validator
  def validate(record)
    return true if # custom model_year and trip logic
    record.errors[:base] << # error message
  end
end

class Vehicle < ActiveRecord::Base
  attr_accessible :make_id, :model_id, :trim_id, :model_year_id
  belongs_to :trim
  belongs_to :model_year

  include ActiveModel::Validations
  validates_with VehicleValidator
end

Answer 2

you can use custom validation method, as described here:

class Vehicle < ActiveRecord::Base
  validate :model_year_valid_for_trim

  def model_year_valid_for_trim
    if #some validation code for model year and trim
      errors.add(:model_years, "some error")
    end
  end

end