Rails View Adapters

This gem provides a DSL for defining adapters that map your model's representations to those of your views, and vice versa.

Adapters are presenters

The adapters can be used to convert a model to its public representation, including associated models, as well as support for arbitrary operations.

FooAdapter.from_model(Foo.find(id)).to_public_hash

Adapters wrap input parameters

The adapters also understand how to "undo" the presentation logic, converting the public representation back to the model or models that (may have) generated it.

Bar.new(BarAdapter.from_public(params).to_params_hash)

Usage

Basics

Define your adapter using the DSL.

# lib/adapters/team_member_adapter.rb
require "rails_view_adapters"
RailsViewAdapters::Adapter.define(:team_member_adapter) do
  map_simple :name, :author
  map_date :join_date, :member_since, date_format
  map_date :created_at, :created_at, date_format
  map_date :updated_at, :updated_at, date_format
  map_bool :admin, :super_user
  hidden_field :secret
  map_from_public :secret do |token|
    { secret: token }
  end
  map_belongs_to :team, :favorite_team, model_class: Team
  map_has_many :posts, :all_posts, sub_method: :body
end

Then require and use it like you would any other class.

require "lib/adapters/team_member_adapter"
TeamMemberAdapter.from_model(TeamMember.find(params[:id])).to_public_hash

Rails

I've found it convenient to create a concern that gets invoked in a controller before_action to automatically grab the right adapter, instantiate it, and use it to modify the params hash. Something like this:

module Adaptation
  extend ActiveSupport::Concern

  included do
    append_before_action :adapt_params
  end

  private
  def adapt_params
    adapter = "#{controller_path.classify.gsub("Controller", "")}Adapter".constantize
    params.merge!(adapter.from_public(params).to_params_hash) {|key,lhs,rhs| rhs}
  end
end

Testing Adapters

Individual needs will vary, but for a reasonable integration test take a look at spec/integration/an_adapter_spec.rb

Do note that the above relies on your controllers and adapters being named predictably.

Documentation

http://www.rubydoc.info/github/mlibrary/rails_view_adapters/