This content originally appeared on DEV Community and was authored by Ivan Ilyukhin
Everything there is related the Rails 6 but also actual for 5 and 4.
- Do not use callbacks if you can - callbacks are incredibly helpful when you need to add a function that should run before/after/around specific lifecycle events. If they do not depend from the context it is possible the best choice. But if the model is used almost everywhere and there are a lot of create/update/destroy events adding new callbacks can drastically reduce the application performance. So I recommend to add them only if you absolutely confident and aware about consequences.
Despite the upper warning, you are decided to add a callback to your model. There are a few things that I recommend to keep in mind.
- Use saved_change_to_attribute? in
after_save/after_updateto except unnecessary calls. - If your callback should be called only after changes in a limited set of attributes, this method can help with it. For example, you have the model User with fields: email, password, first_name and last_name. The goal is to update related certificates only when the first_name or last_name changed.
class User < ApplicationRecord
after_update :update_certifcates,
if: Proc.new{ saved_change_to_first_name? || saved_change_to_last_name? }
private
def update_certificates
User::UpdateCertificates.call(self)
end
end
Use more suitable methods whenever possible - instead of using common methods like:
*_save,*_commit,*_validateis better to use more specific:*_updateor*_create. It will also reduce the count of calls.Use
after_commitinstead ofafter_savewhen you want to complete the action - If something went wrong in theafter_commitcallback there will be an error but the action will be finished because it is called when changes are already flushed to the database. Other callbacks will rollback changes, sometimes it can be useful.Do not run expensive operations in callbacks - better to move them into ActiveJobs
If you know other problems with callbacks or know how to make live easier with them, please share in comments.
Some useful links
- Rails guide about callbacks — Active Record Callbacks
- Rails 6 Callbacks API - ActiveRecord::Callbacks
- Kelly Sutton — 5 Rails Callbacks Best Practices Used at Gusto
This content originally appeared on DEV Community and was authored by Ivan Ilyukhin
Ivan Ilyukhin | Sciencx (2021-05-28T20:06:09+00:00) Small tips that will help you to use ActiveRecord callbacks more efficiently. Retrieved from https://www.scien.cx/2021/05/28/small-tips-that-will-help-you-to-use-activerecord-callbacks-more-efficiently/
Please log in to upload a file.
There are no updates yet.
Click the Upload button above to add an update.