Support callbacks

[tfausak]

We should support ActiveSupport::Callbacks. Tentatively, I want to say we should provide them for:

• initialize
• validate
• execute (or run)

That way you could have code like this:

class Interaction < ActiveInteraction::Base
  set_callback :run, :before, -> (o)     { ... }
  set_callback :run, :after,  -> (o)     { ... }
  set_callback :run, :around, -> (o, &b) { ... }
end

[tfausak]

I wrote an MVP for this feature:

Class.new(ActiveInteraction::Base) do
  include ActiveSupport::Callbacks

  define_callbacks :initialize

  alias_method :_initialize, :initialize

  def initialize(*args, &block)
    run_callbacks(:initialize) { _initialize(*args, &block) }
  end

  set_callback :initialize, :before, -> (_)     { puts 'before' }
  set_callback :initialize, :after,  -> (_)     { puts 'after' }
  set_callback :initialize, :around, -> (_, &b) { puts '(', b.call, ')' }

  def execute; end
end.run

That returns:

before
(
{}
)
after

[tfausak]

Turns out we already support callbacks! ActiveModel gives use :validate callbacks for free.

class Interaction < ActiveInteraction::Base
  set_callback :validate, :before, lambda { |_|
    puts 'before'
  }
  set_callback :validate, :after, lambda { |_|
    puts 'after'
  }
  set_callback :validate, :around, lambda { |_, &block|
    puts 'around'
    block.call
    puts 'around'
  }

  def execute
    puts 'execute'
  end
end

Interaction.run

before
around
around
after
execute