Commands, Events, Dependency Injection

overview.md

class MyCommand
  include Wisper::Publisher

  def initialize(dependencies = {})
    @token_generator = depdendencies.fetch(:token_generator) do
       require 'generate_token'
       GenerateToken.new
     end
  end

  def call(params, &block)
    yield if block_given?
    
    if all_good?
      broadcast(:successful, { id: id })
    else
      broadcast(:failure, { errors: errors })
    end
  end
  
  private
  
  def on(event, handler)
    # ...
  end
end

# app initalization process
System = {}
System[:my_command] = MyCommand.new

# handle request from UI (e.g. in a controller)
System[:my_command].call(params) do
  on(:success) { }
  on(failure) { }
end

The command must be stateless so one instance can be invoked many times over the lifetime of the application.

TODO: The on subscribers need to be temporary since we are using one instance.