2018
The Case for before_validation callback: complex state normalization
Few months ago I wrote a blog post about ActiveRecord before_validation callback and how it is used for wrong reasons and concluded that in most cases this is not something we should be using routinely. However, I missed one appropriate use case for it which might be quite common in Rails apps, so this might be an excellent opportunity to get back to before_validation callback and show its other side.
2017
The Case Against Exotic Usage of :before_validate Callbacks
It’s nothing new that ActiveRecord callbacks are abused in many projects and used for the wrong reasons for many use cases where they can be easily avoided in favor of a much better alternative, like service objects. There is one callback though that is special and quite often used for pretty exotic reasons that have nothing to do with the process when it gets executed - it’s the before_validate callback.