The idea of an object that validates its own state has been made very popular by Rails’ ActiveRecord. We can see this pattern in many places, not only in ORM libraries but in many other gems whenever some sort of validation is needed. Have you ever thought about why we’re allowing invalid state just to…validate data? It doesn’t seem to be a good idea, in fact, it feels like a huge anti-pattern....
We started experimenting with a new validation library under dry-rb organization a couple of months ago, and last month I released the first version of dry-validation. Since then I worked hard on improving it and adding support for i18n. Today, I released dry-validation 0.3.0 with a couple of bug fixes, new features and a complete support for i18n. Before I tell you what it is and how it can help you, let me start by explaining the reasoning behind this project....
I don’t have exact numbers but I believe TDD isn’t really popular amongst rails developers. This shouldn’t be a surprise given that the two of the most complex elements in the rails stack, models and controllers, are very convoluted concepts and are simply hard to test. When you’re building a typical rails application most of the business logic lives in the active record models and controllers. Testing controllers in rails is a bit cumbersome but I still encourage people to write tests for them....
UPDATE: DataMapper 2 was renamed to Ruby Object Mapper (ROM). For more info check out rom-rb.org We have a lot of different Object-Relational Mapper implementations in Ruby (and a ton and a half of Mongo mappers ;)) and it’s probably a good thing. It seems like the only ORM that really matters right now is ActiveRecord although in “the background” we still have DataMapper and Sequel with growing communities. So I’m wondering…what’s the state of these ORMs?...
“Skinny Controller, Fat Model” is a well known best practice in Ruby community. Everybody seems to agree with it and follows it. It’s pretty clear what a skinny controller is. The question is what is a fat model and what should we do if it gets too fat? Even better, what should we do to avoid too fat model? I think many people still confuse Domain Model with ActiveRecord. It’s something more and in this post I will try to explain my new approach to writing Ruby on Rails applications....