Add / Remove Plone object subscribers and send a notification email on state change

add_subscriber.py

# Add a subscriber email to Plone object with Subscribers field

def add_subscriber(self,plone_object,email):

    from Products.PythonScripts.standard import html_quote
    from Products.CMFCore.utils import getToolByName

    plone_utils = getToolByName(self, 'plone_utils', None)
    workflowTool = getToolByName(self, "portal_workflow")

    urltool = getToolByName(self, 'portal_url')
    section_path = urltool.getPortalPath()+ '/'

    obj_query = self.portal_catalog({'meta_type':{'query':['Content Type']},
                                     'review_state':'published',
                                     'id':object_id
                                   })[:1]

    obj_to_subscribe = obj_query.getObject()

    actual_subscribers = list(obj_to_subscribe.getSubscribers())

    if validateEmail(email):
        if email in actual_subscribers:
            message = "Email alreaxy exists."
        else:
            new_subscribers       = actual_subscribers.append(email)
            new_subscribers_tuple = tuple(actual_subscribers)
            obj_to_subscribe.setSubscribers(new_subscribers_tuple)
            obj_to_subscribe.reindexObject()
            message = "Subscriber added to list"
    else:
        message = "Invalid Email."

    return message

def validateEmail(email):
    import re
    if email==None: return False
    return re.match(r"^[a-zA-Z0-9._%-+]+\@[a-zA-Z0-9._%-]+\.[a-zA-Z]{2,}$", email)!=None

send_email.py

# This function can be used to send a notification email when a object state changes.
# It also creates a specific user hash that can be used to unsubscribe from this notifications
# See: do_unsubscribe on unsubscribe.py

def sendEmail(self,state_change):

    import sha

    obj = state_change.object
    mship = self.portal_membership
    mhost = self.MailHost
    adminEmail = self.email_from_address
    administratorEmailAddress = 'put_yout@email.here'

    # Get a list of subscribers on this particular object
    subscribers = obj.getSubscribers()

    for subscriber in subscribers:

        to_string = subscriber

        message = """
        From: %s
        To: %s
        Subject: <SUBJECT LINE>

        <EMAIL TEXT CONTENT>

        --
        To unsubscribe from this notification, click here:
        http://<URL>/unsubscribe?op=%s&email=%s&s=%s
        """

        string_secret = "<YOUR SECRET RANDOM STRING>"
        mail_secret   = sha.new(to_string + obj.getId() + string_secret).hexdigest()

        msg = message % (
            administratorEmailAddress,
            to_string,
            obj.absolute_url(),
            obj.getId(),
            to_string,
            mail_secret
        )

        mh = self.MailHost
        mh.send(msg,
                mto=to_string,
                mfrom=administratorEmailAddress,
                subject="<SUBJECT LINE>")

        print "Notification sent."

    return True

unsubscribe.py

# In this example, the subscribed object must have a field with a list of subscribed people (getSubscribers)
# See: sendEmail on send_email.py

def do_unsubscribe(self,object_id,email,s):

    import sha

    from Products.PythonScripts.standard import html_quote
    from Products.CMFCore.utils import getToolByName

    plone_utils = getToolByName(self, 'plone_utils', None)
    workflowTool = getToolByName(self, "portal_workflow")

    urltool = getToolByName(self, 'portal_url')
    section_path = urltool.getPortalPath()+ '/'

    # Search the object where user is subscribed to
    obj_query = self.portal_catalog({'meta_type':{'query':['Content Type']},
                                     'review_state':'published',
                                     'id':object_id
                                   })[:1]

    obj_to_unsubscribe = obj_query.getObject()

    if (obj_to_unsubscribe):
        actual_subscribers = list(obj_to_unsubscribe.getSubscribers())
        if email in actual_subscribers:
            string_secret = "<YOUR SECRET RANDOM STRING>"
            subscription_secret = sha.new(email + obj_to_unsubscribe.getId() + string_secret).hexdigest()

            # Check if the secret is correct, then we can unsubscribe the user from our field list
            # "s" is the secret we receive from the email URL
            if (subscription_secret == s):
                if (email in actual_subscribers):
                    actual_subscribers.remove(email)
                    new_subscribers_tuple = tuple(actual_subscribers)
                    obj_oposicion.setSubscribers(new_subscribers_tuple)
                    obj_oposicion.reindexObject()
                    message = 'Successfully unsubscribed from this object.'
                else:
                    message = 'You are no longer subscribed.'
    else:
        # Object doesn't exist
        message = 'The object you want to unsubscribe no longer exists.'

    return message