7 Patterns to Refactor Rails Models 7 years later
You may have read the following excellent blogpost by Brian Helmkamp of CodeClimate. It nicely describes 7 types of objects that can be extracted from models and controllers in a Rails-app.
7 Patterns to Refactor Fat ActiveRecord Models https://codeclimate.com/blog/7-ways-to-decompose-fat-activerecord-models/ Brian Helmkamp on Oct 17, 2012.
Here are my thoughts on it, reading it as an experienced rails developer, 7 years later
Don’t Extract Mixins from Fat Models
Be careful about extracting code into app/model/concerns.
Any application with an app/concerns directory is concerning. :thinking_face: I've heard that quote before, probably repeated on an episode of Ruby Rogues.
1. Extract Value Objects
We need to practise this more @standout projects.
2. Extract Service Objects
These are often put in app/services and are pretty common. The name is not the best.
3. Extract Form Objects
These days you can use include ActiveModel::Model` to make it easier.
Check out the "Form Objects in Rails" blogpost by Chris Jeon https://typefast.blog/form-objects-rails/)
4. Extract Query Objects
When scope isn't enough.
5. Introduce View Objects
Helpers are terribly global.
You can't really have private methods since including a module in ruby
will expose all its methods even if they're private.
And by default all helpers are available everywhere
How about view objects then, do they solve the problem?
Yes I think so. But where should they be put? Everything needs to have it's place app/view_models.
6. Extract Policy Objects
The gem pundit by Varvet is very popular for this,
at least within my bubble @standout.
7. Extract Decorators
As Dan Croak of thoughtbot concluded in Evaluating Alternative Decorator Implementations In Ruby.
- Start by wrapping an object with a plain old ruby object
- If you need a transparent interface you can reach for SimpleDelegator and friends