active_model_serializers VS rabl

benchmark.rb

# frozen_string_literal: true

require 'oj'
require 'rabl'
require 'active_model_serializers'
require 'benchmark/memory'
require 'benchmark/ips'

Rabl.configure do |c|
  c.view_paths << 'app/views'
  c.json_engine = Oj if defined?(Oj)
end

ActiveModelSerializers.logger.level = Logger::Severity::UNKNOWN

class ArrayStruct
  def self.new(ary = [])
    ary.map { |hash| OpenStruct.new(hash) }
  end
end

users = [
  { name: 'Bob', age: 27, year: 1976 },
  { name: 'MMM', age: 21, year: 1996 },
  { name: 'NNN', age: 24, year: 1936 },
  { name: 'DDD', age: 25, year: 1978 },
]

class UserSerializer < ActiveModel::Serializer
  attributes :name, :age, :year

  def read_attribute_for_serialization(attr)
    try(attr) || object.send(attr)
  end

  def year
    '1980'
  end
end

def ruby_map(users)
  ActiveModelSerializers::SerializableResource.new(
    users,
    each_serializer: UserSerializer
  ).as_json
end

def rabl_render(users)
  Rabl.render(users, 'welcome/index', format: :hash)
end

puts "\n"
users = ArrayStruct.new(users)

Benchmark.memory do |x|
  x.report('Ruby') { 10_000.times { ruby_map(users) } }
  x.report('Rabl') { 10_000.times { rabl_render(users) } }
  x.compare!
end

puts "---------------------------------------------\n\n"

Benchmark.ips do |x|
  x.report('Ruby') { ruby_map(users) }
  x.report('Rabl') { rabl_render(users) }
  x.compare!
end

puts "\n"

users.json.rabl

# app/views/welcome/index.json.rabl
collection :users
attributes :name, :age

node :year do
  '1980'
end