Rails Idioms

Rails Idioms and Patterns

Rails rewards convention over configuration, Active Record, and RESTful design. Idiomatic Rails = conventional, tested, Hotwire-aware.

Scope: Rails-specific patterns. For Ruby: @.gemini/skills/ruby-idioms/SKILL.md.

Active Record

1. Scopes for reusable queries:

   class Task < ApplicationRecord
     scope :active, -> { where(status: :active) }
     scope :by_priority, -> { order(priority: :desc) }
   end
   

2. Validations in models, not controllers:

   class Task < ApplicationRecord
     validates :title, presence: true, length: { maximum: 200 }
     validates :priority, inclusion: { in: %w[low medium high] }
   end
   

3. includes/preload for eager loading — avoid N+1.

Controllers

1. RESTful actions — only standard 7 actions per controller. Custom actions = new controller.
2. Strong parameters — never mass-assign without permit.
3. Service objects for complex business logic.

Hotwire (7+)

1. Turbo Frames for partial page updates.
2. Turbo Streams for real-time updates.
3. Stimulus for JavaScript sprinkles — minimal JS.

Testing

1. RSpec (preferred):

   RSpec.describe TasksController, type: :request do
     describe 'POST /tasks' do
       it 'creates a task' do
         post tasks_path, params: { task: { title: 'Test', priority: 'high' } }
         expect(response).to have_http_status(:created)
       end
     end
   end
   

2. FactoryBot for test data. Database Cleaner for isolation.

Formatting and Static Analysis

Related

• Ruby Idioms @.gemini/skills/ruby-idioms/SKILL.md
• Database Design Principles @.gemini/skills/database-design-principles/SKILL.md