Ruby on Rails, while being an opinionated framework, promotes several design patterns to make the development process more efficient and maintainable. Here are some prominent design patterns in Rails:
- MVC (Model-View-Controller):
This is the core architectural pattern behind Rails. The `Model` handles the data and business logic, the `View` is responsible for displaying the data, and the `Controller` sits between the Model and View, receiving user input and deciding what to render.
- ActiveRecord:
This pattern is all about object-relational mapping (ORM). It allows developers to interact with database entries using object-oriented syntax. Each database table corresponds to a Rails model, and records in the table map to objects of that model.
- Convention Over Configuration (CoC):
Rails assumes sensible defaults, allowing developers to write less code. If you follow the conventions, such as naming and file placements, Rails will handle many configurations for you.
- Skinny Controller, Fat Model:
It’s advisable to keep controllers lightweight and place more business logic in models. Controllers should mainly be responsible for handling web requests and delegating the heavy lifting to models.
- Decorator Pattern:
Used to add or modify responsibilities of an object dynamically. In Rails, the Draper gem is a popular choice for implementing decorators. It allows adding view-specific logic to models without cluttering them.
- Service Objects:
When business logic becomes too complex for models, service objects come into play. They encapsulate specific pieces of business logic, ensuring models don’t become overly bloated.
- Singleton Pattern:
Ensures a class has only one instance and provides a global point to access it. Rails uses this in its configuration, like `Rails.application`.
- Observer Pattern:
Allows an object (known as the subject) to publish changes to other objects (observers). Though Rails previously had built-in support for this, it’s now extracted as a gem.
Rails employs and promotes numerous design patterns to structure code in a maintainable and efficient manner. Adhering to these patterns not only makes your Rails application more consistent but also easier to understand and scale.
