how to communicate which of multiple before_* callbacks halts execution

Question

before_* callbacks can halt execution by returning false.

I have 3 before_destroy callbacks on a model to halt destruction for several possible reasons. I'd like to tell the user which reason it is, but I'll I get back from the model.destroy is false. How can I send a message out of the model, or determine from the controller which before_destroy callback halted execution?

score 1 · Accepted Answer · answered Aug 24 '11 at 16:30

1

This is a nice question. I don't know if there is a good way to do it. The only thing that comes to my mind is using errors[:base] but it sounds a bit of a hack.

answered Aug 24 '11 at 16:30

lucapette

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1

This doesn't sound like a hack at all. I'd consider this the exactly right way to do this. – Brian Glick Aug 24 '11 at 16:42

score 1 · Answer 2 · edited May 23 '17 at 11:55

There are few good answers here - How do I 'validate' on destroy in rails.

Basicly the solutions will be

errors.add_to_base "Name of the error"

OR

You can define attr_accessor in the model and set them appropriately , even thought I think that this is not the most DRY way , because the object already has the errors attribute hash which should hold the errors.

EX is:

attr_accessor :before_save_error1
attr_accessor :before_save_error2
attr_accessor :before_save_error3

before_destroy :check_for_errors

def check_for_errors 
  error = false
  if error1 # some condition here 
    self.before_save_error1 = true
    error = true 
  elsif error2 # some condition here 
    self.before_save_error2 = true
    error = true
  elseif error3 # some condition here 
    self.before_save_error3 = true
    error = true   
  end 

  error
end

add_to_base is depricated, but I like the accessor idea – pixelearth Aug 24 '11 at 19:08 — pixelearth, Aug 24 '11 at 19:08

score 0 · Answer 3 · answered Aug 24 '11 at 16:52

0

Found the answer. Use:

errors.add :my_key, 'my msg'

Errors is just a hash and can handle any key. Just make sure you don't have name collisions with your attributes.

answered Aug 24 '11 at 16:52

pixelearth

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Yep... it's what I was suggesting ;) – lucapette Aug 24 '11 at 16:58

how to communicate which of multiple before_* callbacks halts execution

3 Answers3