dhh-rails-style

<objective> Apply 37signals/DHH Rails conventions to Ruby and Rails code. This skill provides comprehensive domain expertise extracted from analyzing production 37signals codebases (Fizzy/Campfire) and DHH's code review patterns. </objective> <essential_principles> ## Core Philosophy "The best code is the code you don't write. The second best is the code that's obviously correct." **Vanilla Rails is plenty:** - Rich domain models over service objects - CRUD controllers over custom actions - Concerns for horizontal code sharing - Records as state instead of boolean columns - Database-backed everything (no Redis) - Build solutions before reaching for gems **What they deliberately avoid:** - devise (custom ~150-line auth instead) - pundit/cancancan (simple role checks in models) - sidekiq (Solid Queue uses database) - redis (database for everything) - view_component (partials work fine) - GraphQL (REST with Turbo sufficient) - factory_bot (fixtures are simpler) - rspec (Minitest ships with Rails) - Tailwind (native CSS with layers) **Development Philosophy:** - Ship, Validate, Refine - prototype-quality code to production to learn - Fix root causes, not symptoms - Write-time operations over read-time computations - Database constraints over ActiveRecord validations </essential_principles> <intake> What are you working on? 1. **Controllers** - REST mapping, concerns, Turbo responses, API patterns 2. **Models** - Concerns, state records, callbacks, scopes, POROs 3. **Views & Frontend** - Turbo, Stimulus, CSS, partials 4. **Architecture** - Routing, multi-tenancy, authentication, jobs, caching 5. **Testing** - Minitest, fixtures, integration tests 6. **Gems & Dependencies** - What to use vs avoid 7. **Code Review** - Review code against DHH style 8. **General Guidance** - Philosophy and conventions **Specify a number or describe your task.** </intake> <routing> | Response | Reference to Read | |----------|-------------------| | 1, controller | [controllers.md](./references/controllers.md) | | 2, model | [models.md](./references/models.md) | | 3, view, frontend, turbo, stimulus, css | [frontend.md](./references/frontend.md) | | 4, architecture, routing, auth, job, cache | [architecture.md](./references/architecture.md) | | 5, test, testing, minitest, fixture | [testing.md](./references/testing.md) | | 6, gem, dependency, library | [gems.md](./references/gems.md) | | 7, review | Read all references, then review code | | 8, general task | Read relevant references based on context | **After reading relevant references, apply patterns to the user's code.** </routing> <quick_reference> ## Naming Conventions **Verbs:** `card.close`, `card.gild`, `board.publish` (not `set_style` methods) **Predicates:** `card.closed?`, `card.golden?` (derived from presence of related record) **Concerns:** Adjectives describing capability (`Closeable`, `Publishable`, `Watchable`) **Controllers:** Nouns matching resources (`Cards::ClosuresController`) **Scopes:** - `chronologically`, `reverse_chronologically`, `alphabetically`, `latest` - `preloaded` (standard eager loading name) - `indexed_by`, `sorted_by` (parameterized) - `active`, `unassigned` (business terms, not SQL-ish) ## REST Mapping Instead of custom actions, create new resources: ``` POST /cards/:id/close → POST /cards/:id/closure DELETE /cards/:id/close → DELETE /cards/:id/closure POST /cards/:id/archive → POST /cards/:id/archival ``` ## Ruby Syntax Preferences ```ruby # Symbol arrays with spaces inside brackets before_action :set_message, only: %i[ show edit update destroy ] # Private method indentation private def set_message @message = Message.find(params[:id]) end # Expression-less case for conditionals case when params[:before].present? messages.page_before(params[:before]) else messages.last_page end # Bang methods for fail-fast @message = Message.create!(params) # Ternaries for simple conditionals @room.direct? ? @room.users : @message.mentionees ``` ## Key Patterns **State as Records:** ```ruby Card.joins(:closure) # closed cards Card.where.missing(:closure) # open cards ``` **Current Attributes:** ```ruby belongs_to :creator, default: -> { Current.user } ``` **Authorization on Models:** ```ruby class User < ApplicationRecord def can_administer?(message) message.creator == self || admin? end end ``` </quick_reference> <reference_index> ## Domain Knowledge All detailed patterns in `references/`: | File | Topics | |------|--------| | [controllers.md](./references/controllers.md) | REST mapping, concerns, Turbo responses, API patterns, HTTP caching | | [models.md](./references/models.md) | Concerns, state records, callbacks, scopes, POROs, authorization, broadcasting | | [frontend.md](./references/frontend.md) | Turbo Streams, Stimulus controllers, CSS layers, OKLCH colors, partials | | [architecture.md](./references/architecture.md) | Routing, authentication, jobs, Current attributes, caching, database patterns | | [testing.md](./references/testing.md) | Minitest, fixtures, unit/integration/system tests, testing patterns | | [gems.md](./references/gems.md) | What they use vs avoid, decision framework, Gemfile examples | </reference_index> <success_criteria> Code follows DHH style when: - Controllers map to CRUD verbs on resources - Models use concerns for horizontal behavior - State is tracked via records, not booleans - No unnecessary service objects or abstractions - Database-backed solutions preferred over external services - Tests use Minitest with fixtures - Turbo/Stimulus for interactivity (no heavy JS frameworks) - Native CSS with modern features (layers, OKLCH, nesting) - Authorization logic lives on User model - Jobs are shallow wrappers calling model methods </success_criteria> <credits> Based on [The Unofficial 37signals/DHH Rails Style Guide](https://github.com/marckohlbrugge/unofficial-37signals-coding-style-guide) by [Marc Köhlbrugge](https://x.com/marckohlbrugge), generated through deep analysis of 265 pull requests from the Fizzy codebase. **Important Disclaimers:** - LLM-generated guide - may contain inaccuracies - Code examples from Fizzy are licensed under the O'Saasy License - Not affiliated with or endorsed by 37signals </credits>