How to make a generic callback for any "event" in AASM

Question

I have a State Machine, in a Rails app (with ActiveRecord), defined with AASM and it has a lot of callbacks. Some of these callbacks contain repeated code. E.g, on every state change, we need to build and save a record and send a mail.

event :revision, after: :revision_event_callback do
  # ...
end

event :basic_submit, after: :basic_submit_event_callback do
  # ...
end

event :approve, after: :approve_event_callback do
  # ...
end

def revision_event_callback
  OrderStatusMailer.status_change_report(self, :revision)
  state_changes.build(transition: :revision)
end

def basic_submit_event_callback
  OrderStatusMailer.status_change_report(self, :basic_submit)
  state_changes.build(transition: :basic_submit)
  # ...
  # basic_submit-specific events
end

def approve_event_callback
  OrderStatusMailer.status_change_report(self, :approve)
  state_changes.build(transition: :approve)
end

Intead, I'd like to have one generic callback, and, for the events that need it, a specific in addition.

def event_callback(event_name)
  OrderStatusMailer.status_change_report(self, event_name)
  state_changes.build(transition: event_name)
end

def basic_submit_event_callback
  # basic_submit-specific events
end

Is this possible at all? And, quite important: how would that code have access to the name of the event that was triggered?

score 2 · Answer 1 · answered Oct 07 '16 at 07:27

2

How about doing this.

after_all_events : event_callback

and later define a method

 def event_callback(*args)
    # do stuff here
    after_callback = "after_#{current_event}"
    send(callback, *args) if respond_to?(callback)
 end

answered Oct 07 '16 at 07:27

Arpan Lepcha

176
2
4

score 0 · Accepted Answer · answered Mar 31 '15 at 08:35

0

It's possible. You can – in any callback like :after – request the current event which got triggered, like this:

def event_callback
  event_name = aasm.current_event # e.g. :revision or :revision!
  OrderStatusMailer.status_change_report(self, event_name)
  state_changes.build(transition: event_name)
end

answered Mar 31 '15 at 08:35

alto

609
4
8

And is `event_callback` a magic method that will be added to the calback-chain by default? Or do I still need to add it as `after: :event_callback` in the event-declarations? – berkes Mar 31 '15 at 09:40
No, that's your method from above. You still need to declare it to be called as :after callback (using event :revision, after: :event_callback do...) – alto Apr 01 '15 at 10:10

How to make a generic callback for any "event" in AASM

2 Answers2