ruby-rails

This skill covers Ruby and Ruby on Rails development, including Rails conventions, ActiveRecord patterns, frontend integration, security, and testing.

Core Principles

• Write concise, idiomatic Ruby code with accurate examples
• Adhere to Rails conventions (Convention over Configuration)
• Follow the Ruby Style Guide for formatting consistency
• Leverage Ruby 3.x features like pattern matching and endless methods
• Prefer Rails command-line generators (bin/rails generate ...) over hand-written boilerplate — they keep files consistent with framework conventions and wire up tests/routes automatically
• Use bin/dev to run the local development server (it boots the web process plus any configured watchers) and check logs after significant changes

Naming Conventions

• Use snake_case for files, methods, and variables
• Use CamelCase for classes and modules
• Follow Rails naming conventions for models, controllers, views

Architecture & Performance

• Utilize ActiveRecord for database operations with proper indexing
• Use PostgreSQL in production, with proper indexes, connection pooling, and safe/reversible migrations
• Implement eager loading to prevent N+1 query problems
• Apply fragment caching and Russian Doll caching strategies
• Use service objects for complex business logic
• Follow MVC architecture strictly
• Keep controllers RESTful and focused

Rails 8 Defaults

Rails 8 ships with a "no PaaS needed" stack — favor these built-ins over adding external services unless there's a specific reason not to:

• Solid Queue — database-backed ActiveJob adapter; use it as the default background job backend instead of standing up Redis/Sidekiq unless job volume or feature needs (e.g., Sidekiq Pro batches) require it
• Solid Cache — database-backed cache store; a reasonable default for Rails.cache without a separate Redis/Memcached deployment
• Solid Cable — database-backed Action Cable adapter for WebSockets without Redis
• Propshaft — the default asset pipeline; simpler than Sprockets, just serves fingerprinted files without a bundling step
• Kamal — the default deployment tool for shipping containerized Rails apps to your own servers

Frontend & UI

• Employ Hotwire (Turbo and Stimulus) for standard Rails interactivity and dynamic interactions without full page reloads
• Reach for a Vite-managed JS pipeline (e.g., vite_rails) only when you actually need npm-managed JavaScript (React/Vue components, complex bundling) — don't add it by default
• Design responsively with Tailwind CSS
• Maintain DRY views through helpers and partials
• Use ViewComponents for reusable UI components

Security

• Implement authentication/authorization via Devise or Pundit
• Use strong parameters in controllers to prevent mass assignment vulnerabilities
• Sanitize user inputs appropriately
• Use CSRF protection tokens
• Implement proper session management

Testing

• Write comprehensive Minitest or RSpec coverage for models, controllers, and integration flows, following TDD practices
• Use FactoryBot for test data generation rather than fixtures
• Mock external services; stub predefined return values
• Use shared examples for common behaviors across different contexts
• Ensure each test is independent; avoid shared state between tests

Best Practices

• Keep controllers thin, models fat (but not too fat)
• Use concerns for shared functionality
• Implement background jobs with Sidekiq or ActiveJob
• Use proper database migrations
• Follow RESTful routing conventions