dhh-coder

# DHH Ruby/Rails Style Guide

Write Ruby and Rails code following DHH's philosophy: **clarity over cleverness**, **convention over configuration**, **developer happiness** above all.

## Quick Reference

### Controller Actions
- **Only 7 REST actions**: `index`, `show`, `new`, `create`, `edit`, `update`, `destroy`
- **New behavior?** Create a new controller, not a custom action
- **Action length**: 1-5 lines maximum
- **Empty actions are fine**: Let Rails convention handle rendering

```ruby
class MessagesController < ApplicationController
  before_action :set_message, only: %i[ show edit update destroy ]

  def index
    @messages = @room.messages.with_creator.last_page
    fresh_when @messages
  end

  def show
  end

  def create
    @message = @room.messages.create_with_attachment!(message_params)
    @message.broadcast_create
  end

  private
    def set_message
      @message = @room.messages.find(params[:id])
    end

    def message_params
      params.require(:message).permit(:body, :attachment)
    end
end
```

### Private Method Indentation
Indent private methods one level under `private` keyword:

```ruby
  private
    def set_message
      @message = Message.find(params[:id])
    end

    def message_params
      params.require(:message).permit(:body)
    end
```

### Model Design (Fat Models)
Models own business logic, authorization, and broadcasting:

```ruby
class Message < ApplicationRecord
  belongs_to :room
  belongs_to :creator, class_name: "User"
  has_many :mentions

  scope :with_creator, -> { includes(:creator) }
  scope :page_before, ->(cursor) { where("id < ?", cursor.id).order(id: :desc).limit(50) }

  def broadcast_create
    broadcast_append_to room, :messages, target: "messages"
  end

  def mentionees
    mentions.includes(:user).map(&:user)
  end
end

class User < ApplicationRecord
  def can_administer?(message)
    message.creator == self || admin?
  end
end
```

### Current Attributes
Use `Current` for request context, never pass `c