Plone: reacting to object removal

Question

I\'m wanting to redirect to a container\'s parent after deleting an item within it. To this end, I\'ve tried subscribing to zope.lifecycleevent\'s IObjectRemovedEvent<

Answer 1

Here's another possibility, again from the same genius co-worker:

from zope.interface import implements
from transaction.interfaces import ISavepointDataManager
from transaction._transaction import AbortSavepoint
import transaction

class RedirectDataManager(object):

    implements(ISavepointDataManager)

    def __init__(self, request, url):
        self.request = request
        self.url = url
        # Use the default thread transaction manager.
        self.transaction_manager = transaction.manager

    def tpc_begin(self, transaction):
        pass

    def tpc_finish(self, transaction):
        self.request.response.redirect(self.url)

    def tpc_abort(self, transaction):
        self.request.response.redirect(self.url)

    def commit(self, transaction):
        pass

    def abort(self, transaction):
        pass

    def tpc_vote(self, transaction):
        pass

    def sortKey(self):
        return id(self)

    def savepoint(self):
        """
        This is just here to make it possible to enter a savepoint with this manager active.
        """
        return AbortSavepoint(self, transaction.get())

def redirect_to_trial(obj, event):
    request = getattr(obj, 'REQUEST', None)
    if request:
        trial_url = obj.__parent__.__parent__.absolute_url()
        transaction.get().join(RedirectDataManager(request, trial_url))

I'm now using zcml for subscription to more easily bind it to multiple content types:

This is the solution I've ended up going with, as I find it more explicit about what's happening than doing manual checks to work out if the event I've caught is the event I really want.