SlackBuildsOrg/ruby/wisper

A micro library providing Ruby objects with Publish-Subscribe
capabilities

  Decouple core business logic from external concerns in Hexagonal
  style architectures
  Use as an alternative to ActiveRecord callbacks and Observers in
  Rails apps
  Connect objects based on context without permanence
  Publish events synchronously or asynchronously

Note: Wisper was originally extracted from a Rails codebase but is not
dependant on Rails.