pn-ruby-scaffolding

Ruby backend scaffolding

When to use

• Starting a new Ruby API project (Rails --api or Sinatra).
• Adding a new controller, route, or domain service.
• Establishing service object and error handling patterns.

Rails API-only scaffold

# Create API-only Rails app
rails new my-api --api --database=postgresql
# Omit default Rails test framework only if you use an external test stack (see Rails docs)
cd my-api

# Gemfile essentials
bundle add rack-cors       # CORS
bundle add devise          # auth (optional)
bundle add kaminari        # pagination
bundle add rswag           # OpenAPI docs
bundle add standardrb --group development  # linting

Project structure

app/
  controllers/
    api/
      v1/
        users_controller.rb     # Thin: validate, call service, render
        application_controller.rb
  services/
    users/
      create_user.rb            # Plain Ruby: one public #call method
      find_user.rb
  serializers/
    user_serializer.rb          # Output shaping (blueprinter or JSONAPI)
  models/
    user.rb                     # ActiveRecord model: validations, scopes, associations
config/
  routes.rb

Controller scaffold

# app/controllers/api/v1/users_controller.rb
# frozen_string_literal: true

module Api
  module V1
    class UsersController < ApplicationController
      before_action :authenticate_user!
      before_action :set_user, only: [:show, :update, :destroy]

      def index
        users = User.active.page(params[:page]).per(params[:per_page] || 20)
        render json: { data: UserSerializer.render(users) }
      end

      def show
        render json: { data: UserSerializer.render(@user) }
      end

      def create
        result = Users::CreateUser.new(user_params, current_user).call
        if result.success?
          render json: { data: UserSerializer.render(result.user) }, status: :created
        else
          render json: { error: { code: "VALIDATION_FAILED", message: result.errors.full_messages.join(", ") } },
                 status: :unprocessable_entity
        end
      end

      private

      def set_user
        @user = User.find(params[:id])
      rescue ActiveRecord::RecordNotFound
        render json: { error: { code: "NOT_FOUND", message: "User not found" } }, status: :not_found
      end

      def user_params
        params.require(:user).permit(:email, :name, :role)
      end
    end
  end
end