Rails 3: Model After Filter causing infinite loop

Question

I have the following After Filters:

User Model:

  def check_for_custom_district
    unless self.custom_district.blank?
      district = District.new(:name => custom_district, :state_id => state_id, :school_type_id => school_type_id)

      if district.save(false)
        school = School.new(:name => custom_school, :state_id => state_id, :country_id => 1, :source => "User")
        if school.save(false)
          district.schools << school
          update_attribute(:school_id, school.id)
        end
      end
    end
  end

  def check_for_custom_school
    if self.custom_district.blank? and self.custom_school.present?
      school = School.new(:name => custom_school, :state_id => state_id, :country_id => 1, :source => "User", :school_district_id => district_id)
      school.save(false)
      update_attribute(:school_id, school.id)
    end
  end

I ran some debugging to output the results to the console and the code is hitting the check_for_custom_district method and causing an infinite loop for some reason. Not sure how to stop this... any ideas?

Answer 1

I'm assuming it's an after_save filter.

So lets say you just saved your model.

It triggers the after_save filter. But, in your filter, you actually call update_attribute(:school_id, school.id), which also saves the current model, which triggers your after_save filter again.

That's where your infinite loop is coming from.

One way to get around this might be not to use the after_save filter at all. For example, just re-implement the save method:

def save(*)
  # your custom logic goes here
  super
end