Using ActiveModel::Callbacks

activemodel_callbacks.rb

# ./Gemfile
# $ bundle
source "https://rubygems.org"
gem "activemodel"

###############################################

# foo.rb
# $ bundle exec ruby foo.rb

require 'active_model'

class Foo
  extend ActiveModel::Callbacks

  define_model_callbacks :my_method

  def my_method(raise_zomg = false)
    run_callbacks(:my_method) do
      puts "this is :my_method!"
      raise("ZOMG") if raise_zomg
    end
  end

  before_my_method :before_my_method
  around_my_method :around_my_method
  after_my_method :after_my_method

  def around_my_method
    puts "around_my_method (prepend)"
    begin
      yield
    rescue RuntimeError => e
      puts "Caught that RuntimeError '#{e.message}'"
    end
    puts "around_my_method (append)"
  end

  def after_my_method
    puts "after_my_method"
  end

  def before_my_method
    puts "before_my_method"
  end
end

foo = Foo.new
# foo.my_method
#  Output:
#
#    before_my_method
#    around_my_method (prepend)
#    this is :my_method!
#    around_my_method (append)
#    after_my_method

# Exceptions are reraised!
foo.my_method(:raise_zomg)
#  Output:
#
#    before_my_method
#    around_my_method (prepend)
#    this is :my_method!
#    Caught that RuntimeError 'ZOMG'
#    around_my_method (append)
#    after_my_method