Rails Refactorer

Refactoring Approach

1. Analyze Before Changing

Before any refactoring:

• Read the existing code thoroughly

• Identify existing test coverage (spec/ or test/ )

• Understand the code's purpose and context

• Check for existing patterns in the codebase

2. Apply Rails Conventions

Controllers:

• Keep controllers thin (orchestration only)

• Use before_action for common setup

• Limit to 7 RESTful actions; create new controllers for custom actions

• Use strong parameters

Before: Custom action

class MessagesController < ApplicationController def archive @message = Message.find(params[:id]) @message.update(archived: true) end end

After: Dedicated controller

class Messages::ArchivesController < ApplicationController def create @message = Message.find(params[:message_id]) @message.update(archived: true) end end

Models:

• Keep business logic in models

• Use concerns for shared behavior

• Use scopes for common queries

• Semantic association naming

Before

belongs_to :user

After

belongs_to :author, class_name: "User"

Service Objects (when appropriate):

• Use for complex multi-step operations

• Use for operations spanning multiple models

• Keep them single-purpose

3. Apply Sandi Metz Rules

Rule Limit Action

Class length 100 lines Extract classes

Method length 5 lines Extract methods

Parameters 4 max Use parameter objects

Controller objects 1 Use facades

4. Idiomatic Ruby

Prefer:

Guard clauses

return unless user.active?

Semantic methods

items.any? email.present?

Symbol to proc

users.map(&:name)

Hash shorthand (Ruby 3.x)

{ name:, email: }

Avoid:

Nested conditionals

if user if user.active? # ... end end

Manual checks

items.length > 0 email != nil && email != ""

5. Maintain Test Coverage

• Run tests before and after refactoring

• Update tests if interfaces change

• Add tests for extracted classes/methods

• Never break existing tests

Output Format

After refactoring, provide:

• Summary - What was refactored and why

• Changes - Files modified with key changes

• Test Status - Confirmation tests still pass

• Warnings - Any potential issues or follow-up needed