How to detect if a paperclip attachment was changed in after_save callback?

Question

It looks like Paperclip doesn't honor the ActiveRecord dirty model. How do I detect the change in after_save callback.

class User

  has_attachment :avatar    
  after_save :do_something

  def do_something
    if name_changed?
      #
    end

    # How to determine avatar was changed?
    #if avatar_changed?
    #  #
    #end

  end
end

Note

I know I can detect the change in before_save callback using avatar.dirty? call, but the dirty flag is set to false after save.

I can add a processor, but I need to perform my actions after the model data is saved.

score 29 · Accepted Answer · answered Jan 27 '12 at 05:29

29

You could try accessing the _changed? method for one of the attributes:

if avatar_updated_at_changed?
  # do something
end

answered Jan 27 '12 at 05:29

Dylan Markow

123,080
26
284
201

1

This is what I am doing right now. I am wondering if there is a better method. – Harish Shetty Jan 27 '12 at 06:00
2

Did you ever come up with a better solution? – Mark Boulder Mar 30 '15 at 17:19

score 5 · Answer 2 · answered Aug 16 '12 at 19:39

5

When I need access to this data after save, I typically take this approach:

class Foo

  has_attachment :avatar
  before_save :check_for_avatar_changes
  after_save :do_something

  def do_something
    if @avatar_has_changes
      #
    end
  end

  def check_for_avatar_changes
    @avatar_has_changes = self.avatar.dirty?
  end

end

answered Aug 16 '12 at 19:39

josht

51
1
1

To improve the quality of your post please include how/why your post will solve the problem. – Mick MacCallum Oct 06 '12 at 06:48
There's a problem in the code of check_for_avatar_changes... If the funtion returns false, the model won't get saved, because it's a before_save callback. – Christian Sep 21 '16 at 14:50

How to detect if a paperclip attachment was changed in after_save callback?

2 Answers2