Fast OpenStruct

It was inspired by DynamicClass gem.

The main purpose of this gem is to behave like OpenStruct, but with some extra powers.

Motivation

It's well known that OpenStruct suffers with performance issues and its use is not advised by Rubocop by default. The main issue happens because for each attribute of the instance, it has to create each accessor dynamically.

With this in mind, FastOpenStruct was designed to solve it by caching the accessor methods created for each attribute on the first time. This way FastOpenStruct can be up to 40x faster.

Diferences from OpenStruct

It is 40x faster
It has a cache of the methods that are created
It does not uses @table instance variable
It comes with dig method that works like Hash#dig to access nested attributes
It comes with slice method to slice attributes from FastOpenStruct
It implements some methods of ActiveModel::API and ActiveModel::Serialization, making it useful for some cases (i.e. using it as :class for FactoryBot factories)
It makes a deep initialization of the attributes, converting Hash into FastOpenStruct

Installation

Add this line to your application's Gemfile:

gem 'fast_ostruct'

And then execute:

$ bundle

Or install it yourself as:

$ gem install fast_ostruct

Usage

require 'fast_ostruct'

# INITIALIZATION

my_struct = FastOpenStruct.new(name: 'John')


# ASSIGNMENT 

my_struct.nickname = 'JD'
my_struct['lastname'] = 'Doe'
my_struct[:age] = 30


# ACCESS 

my_struct.name 
# => 'John'
my_struct[:nickname] 
# => 'JD'
my_struct['lastname'] 
# => 'Doe'
my_struct.dig(:age) 
# => 30
my_struct.slice(:name, :age) 
# => { name: 'John', age: 30 }


# ATTRIBUTES HASH

my_struct.attributes 
# => { name: 'John', nickname: 'JD', lastname: 'Doe', age: 30 }

my_struct.attributes(symbolize_keys: true) 
# => { :name => 'John', :nickname => 'JD', :lastname => 'Doe', :age => 30 }

# alias for attributes method:
my_struct.to_h 
my_struct.as_json
my_struct.serializable_hash


# SERIALIZATION

my_struct.to_json 
# => "{\"name\":\"John\",\"nickname\":\"JD\",\"lastname\":\"Doe\",\"age\":30}"


# COMPARISON
 
struct_1 = FastOpenStruct.new(name: 'John')
struct_2 = FastOpenStruct.new(name: 'John')

struct_1 == struct_2 
# => true
struct_1.eql?(struct_2) 
# => true

Configuration

It comes with some default configurations that can be replaced. In Rails applications, create an initializer config/initializers/fast_ostruct.rb and add the following code:

FastOpenStruct.configure do |config|
  config.initialize_options = {
    # It tells if it should make a deep initialization of the attributes, converting Hash to FastOpenStruct. Default: true 
    deep_initialize: true
  }
  
  config.attributes_options = { 
    # It tells if it should symbolize the keys of the attributes. Default: false
    symbolize_keys: false 
  }
end

Benchmarks

Initialization Benchmark

Warming up --------------------------------------
          OpenStruct     4.974k i/100ms
      FastOpenStruct    31.969k i/100ms
Calculating -------------------------------------
          OpenStruct     45.560k (± 8.3%) i/s -    223.830k in   5.058119s
      FastOpenStruct    322.596k (± 3.1%) i/s -      1.630M in   5.071891s
                  with 100.0% confidence

Comparison:
      FastOpenStruct:   322596.0 i/s
          OpenStruct:    45560.0 i/s - 7.09x  (± 0.68) slower
                  with 100.0% confidence

Shared at: https://ips.fastruby.io/62B

Assignment Benchmark

Assignment Benchmark

Warming up --------------------------------------
          OpenStruct   286.228k i/100ms
      FastOpenStruct     1.380M i/100ms
Calculating -------------------------------------
          OpenStruct      2.758M (± 1.6%) i/s -     14.025M in   5.090527s
      FastOpenStruct     13.743M (± 2.5%) i/s -     69.012M in   5.031214s
                  with 100.0% confidence

Comparison:
      FastOpenStruct: 13742868.7 i/s
          OpenStruct:  2758336.0 i/s - 4.98x  (± 0.13) slower
                  with 100.0% confidence

Shared at: https://ips.fastruby.io/62C

Access Benchmark

Warming up --------------------------------------
          OpenStruct   405.434k i/100ms
      FastOpenStruct     1.281M i/100ms
Calculating -------------------------------------
          OpenStruct      4.151M (± 1.0%) i/s -     21.083M in   5.080825s
      FastOpenStruct     12.749M (± 1.1%) i/s -     64.064M in   5.028477s
                  with 100.0% confidence

Comparison:
      FastOpenStruct: 12748892.6 i/s
          OpenStruct:  4151211.2 i/s - 3.07x  (± 0.05) slower
                  with 100.0% confidence

Shared at: https://ips.fastruby.io/62D

All-Together Benchmark

Warming up --------------------------------------
          OpenStruct     4.765k i/100ms
      FastOpenStruct   191.309k i/100ms
Calculating -------------------------------------
          OpenStruct     46.667k (± 3.0%) i/s -    233.485k in   5.020000s
      FastOpenStruct      2.009M (± 1.9%) i/s -     10.139M in   5.054678s
                  with 100.0% confidence

Comparison:
      FastOpenStruct:  2008775.4 i/s
          OpenStruct:    46666.7 i/s - 43.04x  (± 1.60) slower
                  with 100.0% confidence

Shared at: https://ips.fastruby.io/62E

Contributing

Bug reports and pull requests are welcome on GitHub

License

The gem is available as open source under the terms of the MIT License.

revelotech/fast_ostruct