ModestModel

Inspired by Crafting Rails Applications, ModestModel provides an ActiveModel-compliant class that allows you to quickly create simple, table-less models. The intended use is to back interactions with external APIs with Ruby-friendly models rather than raw structured data (such as hashes).

json = MyExternalApi.call('/some/path.json')
attributes_hash = JSON.decode(json)

# => {'name' => 'Michael', 'email' => 'michael@example.com'}

class SampleModel < ModestModel::Base
  attributes :name, :email
end

SampleModel.new(attributes_hash)

# => #<SampleModel @name="Michael"...

ModestModel has been tested and works on MRI 1.8.7 and 1.9.2.

gem install modest_model

gem 'modest_model'

Similar to ActiveRecord models, simply create a class which inherits from ModestModel::Base. You'll need to define some attributes - this is achieved by calling the attributes method passing in the attribute names you require:

class SampleModel < ModestModel::Base
  attributes :name, :email
end

ModestModel includes the following ActiveModel modules:

• ActiveModel::Conversion
• ActiveModel::Naming
• ActiveModel::Translation
• ActiveModel::Serialization
• ActiveModel::Validations
• ActiveModel::AttributeMethods

These allow your ModestModel models to act almost the same as an ActiveRecord model, but without the database. You can mass-assign attributes, add validations, add translations, and call familiar methods like model_name.human and to_json.

ModestModel was extracted from the Mail Form gem described in chapter 2, "Building Models with Active Model", of Crafting Rails Applications by Jose Valim. This chapter therefore provides an excellent in-depth explanation of the inner workings of ModestModel.

This code has been derived from Crafting Rails Applications by Jose Valim, so all credit goes to Jose and Plataforma for granting permission to release this gem.