attr-gather

# define a workflow
class EnhanceProfile
  include Attr::Gather::Workflow

  # contains all the task implementations
  container TasksContainer

  # filter out invalid data using a Dry::Validation::Contract
  # anything that doesn't match this schema will be filtered out
  filter_with_contract do
    params do
      required(:user_id).filled(:integer)

      optional(:user).hash do
        optional(:name).filled(:string)
        optional(:email).filled(:string)
        optional(:gravatar).filled(:string)
        optional(:email_info).hash do
          optional(:deliverable).filled(:bool?)
          optional(:free).filled(:bool?)
        end
      end
    end
  end

  # each task returns a hash of data that will be merged into the result
  task :fetch_post do |t|
    t.depends_on = []
  end

  # will run in parallel
  task :fetch_user do |t|
    t.depends_on = [:fetch_post]
  end

  # will run in parallel
  task :fetch_email_info do |t|
    t.depends_on = [:fetch_user]
  end
end

class PostFetcher
  def call(attrs)
    res = HTTP.get("https://jsonplaceholder.typicode.com/posts/#{attrs[:id]}")
    post = JSON.parse(res.to_s, symbolize_names: true)

    { title: post[:title], user_id: post[:userId], body: post[:body] }
  end
end

class UserFetcher
  # will have access to the PostFetcher attributes here
  def call(attrs)
    res = HTTP.get("https://jsonplaceholder.typicode.com/users/#{attrs[:user_id]}")
    user = JSON.parse(res.to_s, symbolize_names: true)

    { user: { name: user[:name], email: user[:email] } }
  end
end

class EmailInfoFetcher
  # will have access to the PostFetcher attributes here
  def call(user:)
    res = HTTP.timeout(3).get("https://api.trumail.io/v2/lookups/json?email=#{user[:email]}")
    info = JSON.parse(res.to_s, symbolize_names: true)

    # will deep merge with the final result
    { user: { email_info: { deliverable: info[:deliverable], free: info[:free] } } }
  end
end

class MyContainer
  extend Dry::Container::Mixin
  
  register :fetch_post, PostFetcher
  register :fetch_user, UserFetcher
  register :fetch_email_info, EmailInfoFetcher
end

enhancer = EnhanceUserProfile.new
enhancer.call(id: 12).value!

{
  :id => 12,
  :user_id => 2,
  :user => {
    :email => "Shanna@melissa.tv",
    :name => "Ervin Howell",
    :email_info => { :deliverable => true, :free => true },
    :gravatar => "https://www.gravatar.com/avatar/241af7d19a0a7438794aef21e4e19b79"
  }
}

enhancer.to_dot(preview: true) # requires graphviz (brew install graphviz)

gem 'attr-gather'