dynamic_callbacks

⏰ Building a Callback System

Implement custom callbacks to hook into your object’s lifecycle. Use metaprogramming to register and trigger callback methods dynamically.

module Callbackable
  def self.included(base)
    base.extend ClassMethods
  end

  module ClassMethods
    def define_callback(name)
      @callbacks ||= {}
      @callbacks[name] = []

      define_method("on_#{name}") do |&block|
        self.class.instance_variable_get(:@callbacks)[name] << block
      end
    end

    def callbacks
      @callbacks || {}
    end
  end

  def trigger(name)
    self.class.callbacks[name].each { |cb| cb.call(self) }
  end
end

class Task
  include Callbackable
  define_callback :start

  on_start { |task| puts "Task started: \\#{task}" }

  def run
    trigger(:start)
  end
end

Task.new.run  # => "Task started: #<Task:0x...>"