20120709

When a state has a required attribute, Lino will automatically add a corresponding StateAction. This allows for more concise code when defining simple workflows.

For example, the code to define calendar events workflow is now as this:

add = EventState.add_item
add('10', _("Draft"), 'draft')
add('20', _("Scheduled"), 'scheduled',required=dict(states=['','draft']))
add('30', _("Notified"),'notified',required=dict(states=['scheduled']))
add('40', _("Confirmed"),'confirmed',required=dict(states=['scheduled','notified']))
add('50', _("Took place"),'took_place',required=dict(states=['scheduled','notified','confirmed']))
add('60', _("Rescheduled"),'rescheduled',required=dict(states=['scheduled','notified','confirmed']))
add('70', _("Cancelled"),'cancelled',required=dict(states=['scheduled','notified','confirmed']))
add('80', _("Absent"),'absent',required=dict(states=['scheduled','notified','confirmed']))
add('90', _("Obsolete"),'obsolete',required=dict(states=[]))

Previously we had to write, for each line in above code, a whole method similar to the following:

@dd.action(EventState.notified.text,sort_index=11,required=dict(states=['scheduled']))
def mark_notified(self,ar):
    self.state = EventState.notified
    self.save()
    return ar.ui.success_response(refresh=True)

Since application developers will now try to avoid writing complete actions, a workflowed model can now define methods allow_state_FOO that can put additional requirements on a state. For example the following method on lino.modlib.cal.Event causes the “Scheduled” action not to appear as long as the start_time field is empty:

def allow_state_scheduled(self,user):
    if not self.start_time: return False
    return True

The “Register” and “Unregister” actions in the lino.modlib.courses module however are an example of more complex actions that must be defined “by hand”.

TODO:

  • replace before_state_change by state_changed?
  • StateAction would currently not work if workflow_state_field is something else than “state”.
  • The choicelist that opens for Subscription.calendar still ignores the query string. One new feature is lino.core.modeltools.Model.quick_search_fields, though that wasn’t yet the solution.