Unit Measurements Rails

A Rails adaptor that encapsulate measurements and their units in Ruby on Rails.

Harshal V. Ladhe, Master of Computer Science.

Introduction

This gem is designed as a Rails integration for the unit_measurements gem. It provides an ActiveRecord adapter for persisting and retrieving measurement quantity along with its unit, simplifying complex measurement handling within your Rails applications.

Minimum Requirements

Ruby 3.2+ (Download Ruby)
Rails 7.0.0+ (RubyGems - Rails Versions)

Installation

To use unit_measurements-rails in your Rails application, add the following line to your Gemfile:

gem "unit_measurements-rails"

And then execute:

$ bundle install

Or otherwise simply install it yourself as:

$ gem install unit_measurements-rails

Usage

ActiveRecord

This gem provides an ActiveRecord integration allowing you to declare measurement attributes along with their corresponding units in your database schema:

class CreateCubes < ActiveRecord::Migration[7.0]
  def change
    create_table :cubes do |t|
      t.decimal :length_quantity, precision: 10, scale: 2
      t.string :length_unit, limit: 12
      t.timestamps
    end
  end
end

Next, declare an atribute as measurement using measured with its associated unit group class:

class Cube < ActiveRecord::Base
  measured UnitMeasurements::Length, :length
end

This setup allows you to access and assign measurement attributes conveniently:

cube = Cube.new
cube.length = UnitMeasurements::Length.new(5, "ft")
cube.length_quantity   #=> 0.5e1
cube.length_unit       #=> "ft"
cube.length            #=> 5.0 ft

Attribute accessor names are expected to have the _quantity and _unit suffix, and be DECIMAL and VARCHAR types, respectively, and defaults values are accepted.

You can specify multiple measurement attributes simultaneously:

class Cube < ActiveRecord::Base
  measured UnitMeasurements::Length, :length, :width
end

You can customize the quantity and unit accessors of the measurement attribute by specifying them in the quantity_attribute_name and unit_attribute_name options, respectively.

class CubeWithCustomAccessor < ActiveRecord::Base
  measured UnitMeasurements::Length, :length, :width, :height, unit_attribute_name: :size_uom
  measured UnitMeasurements::Weight, :weight, quantity_attribute_name: :width_quantity
end

For a more streamlined approach, predefined methods are available for commonly used types:

#	Unit group	Method name
1	Length or distance	measured_length
2	Weight or mass	measured_weight
3	Time or duration	measured_time
4	Temperature	measured_temperature
5	Area	measured_area
6	Volume	measured_volume
7	Density	measured_density

class CubeWithPredefinedMethods < ActiveRecord::Base
  measured_length :size
  measured_volume :volume
  measured_weight :weight
  measured_density :density
end

Contributing

Contributions to this project are welcomed! To contribute:

Fork this repository
Create a new branch (git checkout -b my-new-feature)
Commit your changes (git commit -am "Add some feature")
Push the changes to your branch (git push origin my-new-feature)
Create new Pull Request