1 files changed, 119 insertions, 2 deletions
diff --git a/src/mailman/workflows/common.py b/src/mailman/workflows/common.py
index 79d57d0ae..d6c372b1e 100644
--- a/src/mailman/workflows/common.py
+++ b/src/mailman/workflows/common.py
@@ -23,15 +23,19 @@ import logging
 from datetime import timedelta
 from email.utils import formataddr
 from enum import Enum
+
+from mailman.app.membership import delete_member
 from mailman.core.i18n import _
 from mailman.email.message import UserNotification
 from mailman.interfaces.address import IAddress
 from mailman.interfaces.bans import IBanManager
 from mailman.interfaces.member import (AlreadySubscribedError, MemberRole,
-                                       MembershipIsBannedError)
+                                       MembershipIsBannedError,
+                                       NotAMemberError)
 from mailman.interfaces.pending import IPendable, IPendings
 from mailman.interfaces.subscriptions import (
-    SubscriptionConfirmationNeededEvent, SubscriptionPendingError, TokenOwner)
+    SubscriptionConfirmationNeededEvent, SubscriptionPendingError, TokenOwner,
+    UnsubscriptionConfirmationNeededEvent)
 from mailman.interfaces.template import ITemplateLoader
 from mailman.interfaces.user import IUser
 from mailman.interfaces.usermanager import IUserManager
@@ -331,3 +335,116 @@ class ModerationMixin:
         else:
             assert self.which is WhichSubscriber.user
             self.subscriber = self.user
+
+
+class UnsubscriptionBase(SubscriptionWorkflowCommon):
+
+    def __init__(self, mlist, subscriber):
+        super().__init__(mlist, subscriber)
+        if IAddress.providedBy(subscriber) or IUser.providedBy(subscriber):
+            self.member = self.mlist.regular_members.get_member(
+                self.address.email)
+
+    def _step_subscription_checks(self):
+        assert self.mlist.is_subscribed(self.subscriber)
+
+    def _step_do_unsubscription(self):
+        try:
+            delete_member(self.mlist, self.address.email)
+        except NotAMemberError:
+            # The member has already been unsubscribed.
+            pass
+        self.member = None
+        assert self.token is None and self.token_owner is TokenOwner.no_one, (
+            'Unexpected active token at end of subscription workflow')
+
+
+class UnRequestMixin:
+
+    def _step_send_confirmation(self):
+        self._set_token(TokenOwner.subscriber)
+        self.push('do_confirm_verify')
+        self.save()
+        notify(UnsubscriptionConfirmationNeededEvent(
+            self.mlist, self.token, self.address.email))
+        raise StopIteration
+
+    def _step_do_confirm_verify(self):
+        # Restore a little extra state that can't be stored in the database
+        # (because the order of setattr() on restore is indeterminate), then
+        # continue with the confirmation/verification step.
+        if self.which is WhichSubscriber.address:
+            self.subscriber = self.address
+        else:
+            assert self.which is WhichSubscriber.user
+            self.subscriber = self.user
+        # Reset the token so it can't be used in a replay attack.
+        self._set_token(TokenOwner.no_one)
+        # Restore the member object.
+        self.member = self.mlist.regular_members.get_member(self.address.email)
+        # It's possible the member was already unsubscribed while we were
+        # waiting for the confirmation.
+        if self.member is None:
+            return
+        # The user has confirmed their unsubscription request
+        self.confirmed = True
+
+
+class UnConfirmationMixin(UnRequestMixin):
+
+    def __init__(self, pre_confirmed=False):
+        self.confirmed = pre_confirmed
+
+    def _step_confirmation_checks(self):
+        # If the unsubscription has been pre-confirmed, then we can skip the
+        # confirmation check can be skipped.
+        if self.confirmed:
+            return
+        # The user must confirm their unsubscription.
+        self.push('send_confirmation')
+
+
+class UnModerationMixin(UnRequestMixin):
+
+    def __init__(self, pre_approved=False):
+        self.approved = pre_approved
+
+    def _step_moderation_checks(self):
+        # Does the moderator need to approve the unsubscription request?
+        if not self.approved:
+            self.push('get_moderator_approval')
+
+    def _step_get_moderator_approval(self):
+        self._set_token(TokenOwner.moderator)
+        self.push('unsubscribe_from_restored')
+        self.save()
+        log.info('{}: held unsubscription request from {}'.format(
+            self.mlist.fqdn_listname, self.address.email))
+        if self.mlist.admin_immed_notify:
+            subject = _(
+                'New unsubscription request to $self.mlist.display_name '
+                'from $self.address.email')
+            username = formataddr(
+                (self.subscriber.display_name, self.address.email))
+            template = getUtility(ITemplateLoader).get(
+                'list:admin:action:unsubscribe', self.mlist)
+            text = wrap(expand(template, self.mlist, dict(
+                member=username,
+                )))
+            # This message should appear to come from the <list>-owner so as
+            # to avoid any useless bounce processing.
+            msg = UserNotification(
+                self.mlist.owner_address, self.mlist.owner_address,
+                subject, text, self.mlist.preferred_language)
+            msg.send(self.mlist)
+        # The workflow must stop running here
+        raise StopIteration
+
+    def _step_unsubscribe_from_restored(self):
+        # Prevent replay attacks.
+        self._set_token(TokenOwner.no_one)
+        if self.which is WhichSubscriber.address:
+            self.subscriber = self.address
+        else:
+            assert self.which is WhichSubscriber.user
+            self.subscriber = self.user