Trigger email send when a rails model boolean field is set to true instead of false

Question

I have two models in my application. Families has_many Individuals's. individuals's belongs_to Families.

I'm trying to make it so that when a boolean field in the Families model is set to "true" an email is sent to all of the email addresses stored against Individuals when the family is "updated".

Can anyone help with this? I've been able to get ActiveMailer sending an email when an Individual is created easily enough, but cannot find a way to trigger on the update of a specific field?

Any help would be greatly appreciated!

Answer 1

Maybe you could use an after filter?

on the Family model

after_update :email_individuals


private
def email_individuals
  if boolean_field_changed?
    individuals.each do |i|
      // send out emails here
    end
  end
end

The next step would be to move this out of the request cycle and into a queue.

Hope I grokked your question properly.

Answer 2

Toby has the right idea but I disagree that this should be implemented in the controller... this is much better suited to a model after_update callback. something like this:

def update_fired
  if yourfield_changed?
     #send mail here
  end
end

Then just make sure in your model you set the method to be the after_update callback

Answer 3

Easiest way would be to add something to the update action of your controller

if individual.boolean_field_changed? and individual.boolean_field
  individuals.each do |ind|
    Mailer.deliver_mail(ind)
  end
end

Rails has an API for detecting changes in model fields (in the above case you add _changed? to the field name and it will tell you if the field has been changed.