Mediators

Pliny encourages the use of the Mediator pattern to keep your endpoints lean and your models focused.

The basic idea is very simple: move any workflow or interaction between objects into a new class. You want to avoid things like a Sinatra post block starting a transaction, after_save hooks sending emails, etc.

Create a new mediator like:

$ pliny-generate mediator artists/creator
created mediator file ./lib/mediators/artists/creator.rb
created test ./spec/mediators/artists/creator_spec.rb

The basic class is trivial:

module Mediators::Artists
  class Creator < Mediators::Base
    def initialize
    end

    def call
    end
  end
end

The only thing Pliny sets in the base mediator class is a shortcut to initialize and call. So you can trigger the code above with:

Mediators::Artists::Creator.run

Needless to say mediators only exist to wrap complex workflows and interactions. Do not create a mediator for every single endpoint in your API – if all you need is to call User.create then do that directly.

Further reading:

• The Mediator Pattern