Method telling whether an ActiveRecord has been newly created (and already persisted)?

rubyonrails-talk
1

Several times I found myself of need of a method that tells whether an ActiveRecord instance has just been created. For example, when writing generic activity logging code that needs to know whether model is newly created as opposed to updated, but the invocation is in a service outside of the model itself and thus I can’t just write after_create and after_update hooks, except perhaps just to set custom flags for the service to inspect.

It’s not the same as new_record? because new_record? is only true before record is saved, not after save. I’m thinking newly_created? or just_created? name. Calling it created? would be too ambiguous and higher chance to clash with similarly named method by application developers in their own code.

Essentially new_record? to newly_created? is the same as marked_for_destruction? is to destroyed?, or as changes is to previous_changes.

In my app I’ve implemented the code like this:

def newly_created? id_changes = previous_changes[‘id’] id_changes && id_changes.last && !id_changes.first end

Is this something anyone else found doing, and would it be helpful for ActiveRecord to provide this method?

2

Not entirely sure exactly what you mean by newly created. Do you mean not updated since created (in which case you could compare created_at and updated_at) or only just recently created (in which case you could compare created_at to time now) or created within the current request (in which case just remember in code that you have just created it) or something else.

Colin

3

First of all you should give a rigour definition of “newly_created?”. I mean, what should we consider “newly created”? A record created 1 second ago? 10 mins ago, or 1 day ago?