Ruby on Rails Q & A


What are the Rails design patterns?

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:


  1. 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.


  1. 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.


  1. 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.


  1. 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.


  1. 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.


  1. 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.


  1. 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`.


  1. 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.

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Senior Software Engineer with a focus on remote work. Proficient in Ruby on Rails. Expertise spans y6ears in Ruby on Rails development, contributing to B2C financial solutions and data engineering.