Rails: check if the model was really saved in after_save
ActiveRecord use to call after_save callback each time save method is called even if the model was not changed and no insert/update query spawned.
This is the default behaviour actually. And that is ok in most cases.
But some of the after_save callbacks are sensitive to the thing that if the model was actually saved or not.
Is there a way to determine if the model was actually saved in the after_save?
I am running the following test code:
开发者_如何学编程class Stage < ActiveRecord::Base
after_save do
pp changes
end
end
s = Stage.first
s.name = "q1"
s.save!
ActiveRecord use to call after_save callback each time save method is called even if the model was not changed and no insert/update query spawned.
ActiveRecord executes :after_save callbacks each time the record is successfully saved regardless it was changed.
# record invalid, after_save not triggered
Record.new.save
# record valid, after_save triggered
r = Record.new(:attr => value)
# record valid and not changed, after_save triggered
r.save
What you want to know is if the record is changed, not if the record is saved.
You can easily accomplish this using record.changed?
class Record
after_save :do_something_if_changed
protected
def do_something_if_changed
if changed?
# ...
end
end
end
After a save, check to see if the object saved is a new object
a = ModelName.new
a.id = 1
a.save
a.new_record?
#=> false
For anyone else landing here, latest rails 5 has a model method saved_changes?
and a corresponding method saved_changes
which shows those changes.
book = Book.first
book.saved_changes?
=> false
book.title = "new"
book.save
book.saved_changes?
=> true
book.saved_changes
=> {"title" => ["old", "new"]},
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