Service layer

base.rb

# app/services/pages/base.rb
module Pages
	class Base
		include Service
		
		def self.call(account: nil, user: nil, page: nil, param: nil)
			new(account: account, user: user, page: page).call( param: param)
		end
		
		def initialize(account: nil, user: nil, page: nil)
			@account = account
			@user = user
			@page = page || Page.new(account: @account)
		end
		
		# some methods
	end
end

create.rb

# app/services/pages/create.rb
module Pages
	class Create < Base
		def call(param)
			#some logic
			@page
		end
	end
end

pages_controller.rb

# app/controllers/pages_controller.rb
class PagesController < ApplicationController 
	# some methods
	
	def create
		@page = Pages::Create.call(account: current_account, user: current_user, params: page_params)
		respond_to do |format|
			if @page.persisted? && @page.errors.empty?
				format.json {}
			else
				format.json{ render json: @page.errors, status: :unprocessable_entity}
			end
		end
	end
	
	#....
end

service.rb

# app/services/service.rb
module Service
	extend ActiveSupport::Concern
	
	included do 
		def round_to_i(num)
			num.round.to_i
		end
		
		def allow_state_update?(object)
			if object.respond_to?('workflow_state_changed?') && object.workflow_state_changed?
				if Pundit.policy(@user, object).allow_state_update?
					true
				else
					object.errors.add(:state, "You don't have permissions to update this attribute to #{object.workflow_state.try(:humanize)}")
					false
				end
			else
				true
			end
		end
		# ....
	end