Rails ActiveRecord conditionally protect an attribute from modification

Question

I have a Message model with a content attribute (string) and a sent attribute (boolean). A message's content should be modifiable until it's been sent, after which that field should become read only. (Other attributes can still be modifiable, such as message_opened).

How can I accomplish this? I've looked into overriding readonly? (only applies at the record level), attr_readonly (not conditional), and validations (don't know how to make the validation of the content depend on both its old value and the sent field).

Community · Accepted Answer · 2017-05-23 12:10:39Z

3

Turns out validations are the right approach: create a custom validation that uses attribute_changed? ("attribute" is the name of the attribute, in this case, "content") and a conditional validation.

Message.rb:

validate_on_update :reject_modifying_content, if: :sent?

def reject_modifying_content
 errors[:content] << "can not be changed!" if self.content_changed?
end

See Rails 3 check if attribute changed, Setting a field to read-only in Rails after it's created and http://api.rubyonrails.org/classes/ActiveModel/Dirty.html for more information.

edited May 23, 2017 at 12:10

CommunityBot

11 silver badge

answered May 1, 2013 at 11:39

Sherwin Yu

3,2403 gold badges27 silver badges42 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

JAR.JAR.beans · Accepted Answer · 2015-09-13 05:13:52Z

0

Going over possible answers, I think setting the field as:

attr_readonly

Is the best option is it will totally protect that field without custom code needed.

Attributes listed as readonly will be used to create a new record but update operations will ignore these fields.

answered Sep 13, 2015 at 5:13

JAR.JAR.beans

10.1k5 gold badges47 silver badges61 bronze badges

Collectives™ on Stack Overflow

Rails ActiveRecord conditionally protect an attribute from modification

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related