Trackable extension


The GobiertoCommon::Trackable module extends the current Form class by
providing a way to track changes in a specific resource, which can
correspond to a well-known ActiveRecord model.

Note: This is still under development.


An implementation sample can be found at
GobiertoAdmin::GobiertoBudgetConsultations::ConsultationForm. There are just a few sections to highlight:

First of all, the GobiertoCommon::Trackable extension must be loaded
by prepending the module in the corresponding class. e.g.:

module GobiertoAdmin
  module GobiertoBudgetConsultations
    class ConsultationForm

      prepend ::GobiertoCommon::Trackable

After having loaded the extension, its behavior can be configured
through a quite simple DSL. We would need to specify which will
be the main resource to watch (it should correspond to a ActiveRecord
model for now) to produce the notification events. In this case, we're
delegating it in the consultation method, as follows:

trackable_on :consultation

It also provides syntax to limit the attributes that are going to be
tracked. In this case, only changes in title, visibility_level,
opens_on and closes_on attributes will be notified:

notify_changed :title
notify_changed :visibility_level
notify_changed :opens_on
notify_changed :closes_on

To let the extension track those changes, it is also required to wrap
the saving action within a run_callbacks(:save) block since it makes
use of the ActiveModel::Dirty
feature. The model's callbacks are already defined so this is the only
needed change:

run_callbacks(:save) do

Finally, there is a method that can be defined at class level to limit
notifications based on its own business logic. It is not required so the
notification will be performed if no notify? method is defined. e.g.:

def notify?