Ruby on Rails Guide

Applies to: Rails 7+, Ruby 3.2+, Hotwire/Turbo, ActiveRecord, Action Cable

Core Principles

1. Convention over Configuration: Follow Rails conventions -- naming, directory structure, RESTful routes
2. Fat Models, Thin Controllers: Business logic in models and service objects, controllers handle request/response only
3. DRY: Use concerns, partials, helpers, and shared services to avoid repetition
4. RESTful by Default: Design resources around standard CRUD actions before adding custom routes
5. Security by Default: CSRF, XSS protection, strong parameters, and parameterized queries are built in

When to Use Rails

Good fit: Full-stack web apps, MVPs, CMS, e-commerce, SaaS, Hotwire/Turbo SPA-like UX, API backends.

Consider alternatives: Minimal microservices (Sinatra, Hanami), heavy real-time streaming, strict type safety needs (Rust, Go).

Project Structure