Improvements around the waiting list (#2219)

* Waiting list: Support for seated events, pre-fill customer email address

* Allow people to remove themselves

* Update src/pretix/base/settings.py

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/control/views/waitinglist.py

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/control/views/waitinglist.py

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/control/views/waitinglist.py

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Update src/pretix/presale/views/waiting.py

Co-authored-by: Richard Schreiber <schreiber@rami.io>

* Resolve a review note

* Review notes

* Fix linter issues

* Fix import

Co-authored-by: Richard Schreiber <schreiber@rami.io>

src/pretix/base/email.py

@@ -462,6 +462,16 @@ def base_placeholders(sender, **kwargs):
             lambda waiting_list_entry, event: (waiting_list_entry.subevent or event).get_date_from_display(),
             lambda event: (event if not event.has_subevents or not event.subevents.exists() else event.subevents.first()).get_date_from_display()
         ),
+        SimpleFunctionalMailTextPlaceholder(
+            'url_remove', ['waiting_list_entry', 'event'],
+            lambda waiting_list_entry, event: build_absolute_uri(
+                event, 'presale:event.waitinglist.remove'
+            ) + '?voucher=' + waiting_list_entry.voucher.code,
+            lambda event: build_absolute_uri(
+                event,
+                'presale:event.waitinglist.remove',
+            ) + '?voucher=68CYU2H6ZTP3WLK5',
+        ),
         SimpleFunctionalMailTextPlaceholder(
             'url', ['waiting_list_entry', 'event'],
             lambda waiting_list_entry, event: build_absolute_uri(

src/pretix/base/models/waitinglist.py

@@ -21,8 +21,9 @@
 #
 from datetime import timedelta
 
-from django.core.exceptions import ValidationError
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.db import models, transaction
+from django.db.models import F, Q, Sum
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_scopes import ScopedManager
@@ -114,9 +115,12 @@ class WaitingListEntry(LoggedModel):
         return '%s waits for %s' % (str(self.email), str(self.item))
 
     def clean(self):
-        WaitingListEntry.clean_duplicate(self.email, self.item, self.variation, self.subevent, self.pk)
-        WaitingListEntry.clean_itemvar(self.event, self.item, self.variation)
-        WaitingListEntry.clean_subevent(self.event, self.subevent)
+        try:
+            WaitingListEntry.clean_duplicate(self.email, self.item, self.variation, self.subevent, self.pk)
+            WaitingListEntry.clean_itemvar(self.event, self.item, self.variation)
+            WaitingListEntry.clean_subevent(self.event, self.subevent)
+        except ObjectDoesNotExist:
+            raise ValidationError('Invalid input')
 
     def save(self, *args, **kwargs):
         update_fields = kwargs.get('update_fields', [])
@@ -147,6 +151,34 @@ class WaitingListEntry(LoggedModel):
         )
         if availability[1] is None or availability[1] < 1:
             raise WaitingListException(_('This product is currently not available.'))
+
+        ev = self.subevent or self.event
+        if ev.seat_category_mappings.filter(product=self.item).exists():
+            # Generally, we advertise the waiting list to be based on quotas only. This makes it dangerous
+            # to use in combination with seating plans. If your event has 50 seats and a quota of 50 and
+            # default settings, everything is fine and the waiting list will work as usual. However, as soon
+            # as those two numbers diverge, either due to misconfiguration or due to intentional features such
+            # as our COVID-19 minimum distance feature, things get ugly. Theoretically, there could be
+            # significant quota available but not a single seat! The waiting list would happily send out vouchers
+            # which do not work at all. Generally, we consider this a "known bug" and not fixable with the current
+            # design of the waiting list and seating features.
+            # However, we've put in a simple safeguard that makes sure the waiting list on its own does not screw
+            # everything up. Specifically, we will not send out vouchers if the number of available seats is less
+            # than the number of valid vouchers *issued through the waiting list*. Things can still go wrong due to
+            # manually created vouchers, manually blocked seats or the minimum distance feature,  but this reduces
+            # the possible damage a bit.
+            num_free_seats_for_product = ev.free_seats().filter(product=self.item).count()
+            num_valid_vouchers_for_product = self.event.vouchers.filter(
+                Q(valid_until__isnull=True) | Q(valid_until__gte=now()),
+                block_quota=True,
+                item_id=self.item_id,
+                subevent_id=self.subevent_id,
+                waitinglistentries__isnull=False
+            ).aggregate(free=Sum(F('max_usages') - F('redeemed')))['free'] or 0
+            free_seats = num_free_seats_for_product - num_valid_vouchers_for_product
+            if not free_seats:
+                raise WaitingListException(_('No seat with this product is currently available.'))
+
         if self.voucher:
             raise WaitingListException(_('A voucher has already been sent to this person.'))
         if '@' not in self.email:

src/pretix/base/services/waitinglist.py

@@ -22,12 +22,14 @@
 import sys
 from datetime import timedelta
 
-from django.db.models import Exists, OuterRef, Q
+from django.db.models import Exists, F, OuterRef, Q, Sum
 from django.dispatch import receiver
 from django.utils.timezone import now
 from django_scopes import scopes_disabled
 
-from pretix.base.models import Event, User, WaitingListEntry
+from pretix.base.models import (
+    Event, SeatCategoryMapping, User, WaitingListEntry,
+)
 from pretix.base.models.waitinglist import WaitingListException
 from pretix.base.services.tasks import EventTask
 from pretix.base.signals import periodic_task
@@ -43,6 +45,19 @@ def assign_automatically(event: Event, user_id: int=None, subevent_id: int=None)
 
     quota_cache = {}
     gone = set()
+    seats_available = {}
+
+    for m in SeatCategoryMapping.objects.filter(event=event).select_related('subevent'):
+        # See comment in WaitingListEntry.send_voucher() for rationale
+        num_free_seets_for_product = (m.subevent or event).free_seats().filter(product_id=m.product_id).count()
+        num_valid_vouchers_for_product = event.vouchers.filter(
+            Q(valid_until__isnull=True) | Q(valid_until__gte=now()),
+            block_quota=True,
+            item_id=m.product_id,
+            subevent_id=m.subevent_id,
+            waitinglistentries__isnull=False
+        ).aggregate(free=Sum(F('max_usages') - F('redeemed')))['free'] or 0
+        seats_available[(m.product_id, m.subevent_id)] = num_free_seets_for_product - num_valid_vouchers_for_product
 
     qs = WaitingListEntry.objects.filter(
         event=event, voucher__isnull=True
@@ -70,6 +85,11 @@ def assign_automatically(event: Event, user_id: int=None, subevent_id: int=None)
                 gone.add((wle.item, wle.variation, wle.subevent))
                 continue
 
+            if (wle.item_id, wle.subevent_id) in seats_available:
+                if seats_available[wle.item_id, wle.subevent_id] < 1:
+                    gone.add((wle.item, wle.variation, wle.subevent))
+                    continue
+
             quotas = (wle.variation.quotas.filter(subevent=wle.subevent)
                       if wle.variation
                       else wle.item.quotas.filter(subevent=wle.subevent))
@@ -91,6 +111,9 @@ def assign_automatically(event: Event, user_id: int=None, subevent_id: int=None)
                         quota_cache[q.pk][0] if quota_cache[q.pk][0] > 1 else 0,
                         quota_cache[q.pk][1] - 1 if quota_cache[q.pk][1] is not None else sys.maxsize
                     )
+
+                if (wle.item_id, wle.subevent_id) in seats_available:
+                    seats_available[wle.item_id, wle.subevent_id] -= 1
             else:
                 gone.add((wle.item, wle.variation, wle.subevent))
 

src/pretix/base/settings.py

@@ -1746,6 +1746,12 @@ Please note that this link is only valid within the next {hours} hours!
 We will reassign the ticket to the next person on the list if you do not
 redeem the voucher within that timeframe.
 
+If you do NOT need a ticket any more, we kindly ask you to click the
+following link to let us know. This way, we can send the ticket as quickly
+as possible to the next person on the waiting list:
+
+{url_remove}
+
 Best regards,
 Your {event} team"""))
     },

src/pretix/control/templates/pretixcontrol/event/settings.html

@@ -256,9 +256,22 @@
                 <div class="alert alert-info">
                     {% blocktrans trimmed %}
                         The waiting list currently is not compatible with some advanced features of pretix such as
-                        seating plans, add-on products or product bundles.
+                        add-on products or product bundles.
                     {% endblocktrans %}
                 </div>
+                <div class="alert alert-info">
+                    {% blocktrans trimmed %}
+                        The waiting list determines availability mainly based on quotas. If you use a seating plan and your
+                        number of available seats is less than the available quota, you might run into situations where
+                        people are sent an email from the waiting list but still are unable to book a seat.
+                    {% endblocktrans %}
+                    <strong>
+                        {% blocktrans trimmed %}
+                            Specifically, this means the waiting list is not safe to use together with the minimum distance
+                            feature of our seating plan module.
+                        {% endblocktrans %}
+                    </strong>
+                </div>
                 {% bootstrap_field sform.waiting_list_enabled layout="control" %}
                 {% bootstrap_field sform.waiting_list_auto layout="control" %}
                 {% bootstrap_field sform.waiting_list_hours layout="control" %}

src/pretix/control/views/waitinglist.py

@@ -50,7 +50,7 @@ from django.views import View
 from django.views.generic import ListView
 from django.views.generic.edit import DeleteView
 
-from pretix.base.models import Item, WaitingListEntry
+from pretix.base.models import Item, Quota, WaitingListEntry
 from pretix.base.models.waitinglist import WaitingListException
 from pretix.base.services.waitinglist import assign_automatically
 from pretix.base.views.tasks import AsyncAction
@@ -239,8 +239,24 @@ class WaitingListView(EventPermissionRequiredMixin, WaitingListQuerySetMixin, Pa
                         if wle.variation
                         else wle.item.check_quotas(count_waitinglist=False, subevent=wle.subevent, _cache=quota_cache)
                     )
+                if wle.availability[0] == Quota.AVAILABILITY_OK and ev.seat_category_mappings.filter(product=wle.item).exists():
+                    # See comment in WaitingListEntry.send_voucher() for rationale
+                    num_free_seats_for_product = ev.free_seats().filter(product=wle.item).count()
+                    num_valid_vouchers_for_product = self.request.event.vouchers.filter(
+                        Q(valid_until__isnull=True) | Q(valid_until__gte=now()),
+                        block_quota=True,
+                        item_id=wle.item_id,
+                        subevent=wle.subevent_id,
+                        waitinglistentries__isnull=False
+                    ).aggregate(free=Sum(F('max_usages') - F('redeemed')))['free'] or 0
+                    free_seats = num_free_seats_for_product - num_valid_vouchers_for_product
+                    wle.availability = (
+                        Quota.AVAILABILITY_GONE if free_seats == 0 else wle.availability[0],
+                        min(free_seats, wle.availability[1])
+                    )
+
                 itemvar_cache[(wle.item, wle.variation, wle.subevent)] = wle.availability
-            if wle.availability[0] == 100:
+            if wle.availability[0] == Quota.AVAILABILITY_OK:
                 any_avail = True
 
         ctx['any_avail'] = any_avail

src/pretix/presale/forms/waitinglist.py

@@ -20,6 +20,7 @@
 # <https://www.gnu.org/licenses/>.
 #
 from django import forms
+from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.utils.translation import gettext_lazy as _
 from phonenumber_field.formfields import PhoneNumberField
 from phonenumbers.data import _COUNTRY_CODE_TO_REGION_CODE
@@ -28,7 +29,8 @@ from pretix.base.forms.questions import (
     NamePartsFormField, WrappedPhoneNumberPrefixWidget, guess_country,
 )
 from pretix.base.i18n import get_babel_locale, language
-from pretix.base.models import WaitingListEntry
+from pretix.base.models import Quota, WaitingListEntry
+from pretix.presale.views.event import get_grouped_items
 
 
 class WaitingListForm(forms.ModelForm):
@@ -40,8 +42,35 @@ class WaitingListForm(forms.ModelForm):
 
     def __init__(self, *args, **kwargs):
         self.event = kwargs.pop('event')
+        self.channel = kwargs.pop('channel')
         super().__init__(*args, **kwargs)
 
+        choices = [
+            ('', '')
+        ]
+        items, display_add_to_cart = get_grouped_items(
+            self.event, self.instance.subevent, require_seat=None
+        )
+        for i in items:
+            if not i.allow_waitinglist:
+                continue
+
+            if i.has_variations:
+                for v in i.available_variations:
+                    if v.cached_availability[0] == Quota.AVAILABILITY_OK:
+                        continue
+                    choices.append((f'{i.pk}-{v.pk}', f'{i.name} – {v.value}'))
+
+            else:
+                if i.cached_availability[0] == Quota.AVAILABILITY_OK:
+                    continue
+                choices.append((f'{i.pk}', f'{i.name}'))
+
+        self.fields['itemvar'] = forms.ChoiceField(
+            label=_('Product'),
+            choices=choices,
+        )
+
         event = self.event
 
         if event.settings.waiting_list_names_asked:
@@ -73,3 +102,23 @@ class WaitingListForm(forms.ModelForm):
                 )
         else:
             del self.fields['phone']
+
+    def clean(self):
+        try:
+            iv = self.data.get('itemvar', '')
+            if '-' in iv:
+                itemid, varid = iv.split('-')
+            else:
+                itemid, varid = iv, None
+
+            self.instance.item = self.instance.event.items.get(pk=itemid)
+            if varid:
+                self.instance.variation = self.instance.item.variations.get(pk=varid)
+            else:
+                self.instance.variation = None
+
+        except ObjectDoesNotExist:
+            raise ValidationError(_("Invalid product selected."))
+
+        data = super().clean()
+        return data

src/pretix/presale/templates/pretixpresale/event/index.html

@@ -211,6 +211,30 @@
                         {% eventsignal event "pretix.presale.signals.render_seating_plan" request=request %}
                     {% endif %}
                 {% endif %}
+
+                {% if waitinglist_seated %}
+                    <aside class="front-page" aria-labelledby="waiting-list">
+                        <h3 id="waiting-list">{% trans "Waiting list" %}</h3>
+                        <div class="row">
+                            <div class="col-md-8 col-sm-6 col-xs-12">
+                                <p>
+                                    {% blocktrans trimmed %}
+                                        Some of the categories in the seating plan above are currently sold out. If you want, you can add yourself to the
+                                        waiting list. We will then notify if seats are available again.
+                                    {% endblocktrans %}
+                                </p>
+                            </div>
+                            <div class="col-md-4 col-sm-6 col-xs-12">
+                                <a href="{% eventurl event "presale:event.waitinglist" cart_namespace=cart_namespace|default_if_none:"" %}{% if subevent %}?subevent={{ subevent.pk }}{% endif %}" class="btn btn-default btn-block">
+                                    <span class="fa fa-plus-circle" aria-hidden="true"></span>
+                                    {% trans "Join waiting list" %}
+                                </a>
+                            </div>
+                            <div class="clearfix"></div>
+                        </div>
+                    </aside>
+                {% endif %}
+
                 {% include "pretixpresale/event/fragment_product_list.html" %}
                 {% if ev.presale_is_running and display_add_to_cart %}
                     <section class="front-page">

src/pretix/presale/templates/pretixpresale/event/waitinglist.html

@@ -6,13 +6,6 @@
     <form action="" method="post">
         {% csrf_token %}
         <div class="form-horizontal">
-            <div class="form-group">
-                <label class="col-md-3 control-label" for="id_email">{% trans "Product" %}</label>
-                <div class="col-md-9">
-                    <input class="form-control" readonly="readonly"
-                           value="{{ item.name }}{% if variation %} – {{ variation.value }}{% endif %}">
-                </div>
-            </div>
             {% if subevent %}
                 <div class="form-group">
                     <label class="col-md-3 control-label" for="id_email">{% trans "Event" %}</label>

src/pretix/presale/templates/pretixpresale/event/waitinglist_remove.html

@@ -0,0 +1,20 @@
+{% extends "pretixpresale/event/base.html" %}
+{% load i18n eventurl bootstrap3 %}
+{% block title %}{% trans "Waiting list" %}{% endblock %}
+{% block content %}
+    <h2>{% trans "Remove me from the waiting list" %}</h2>
+    <form action="" method="post">
+        {% csrf_token %}
+        <p>
+            {% blocktrans trimmed %}
+                You have been selected from our waiting list to buy a ticket. If you do not need the ticket any more, please be so kind and remove your ticket from the list
+                so we can pass it on to the next person waiting as quickly as possible!
+            {% endblocktrans %}
+        </p>
+        <p class="text-center">
+            <button type="submit" class="btn btn-danger btn-lg">
+                {% trans "Yes, remove my ticket" context "waitinglist" %}
+            </button>
+        </p>
+    </form>
+{% endblock %}

src/pretix/presale/urls.py

@@ -68,6 +68,7 @@ frame_wrapped_urls = [
     re_path(r'^(?P<subevent>[0-9]+)/seatingframe/$', pretix.presale.views.event.SeatingPlanView.as_view(),
             name='event.seatingplan'),
     re_path(r'^(?P<subevent>[0-9]+)/$', pretix.presale.views.event.EventIndex.as_view(), name='event.index'),
+    re_path(r'^waitinglist/remove$', pretix.presale.views.waiting.WaitingRemoveView.as_view(), name='event.waitinglist.remove'),
     re_path(r'^waitinglist', pretix.presale.views.waiting.WaitingView.as_view(), name='event.waitinglist'),
     re_path(r'^$', pretix.presale.views.event.EventIndex.as_view(), name='event.index'),
 ]

src/pretix/presale/views/event.py

@@ -180,7 +180,7 @@ def get_grouped_items(event, subevent=None, voucher=None, channel='web', require
     ).order_by('category__position', 'category_id', 'position', 'name')
     if require_seat:
         items = items.filter(requires_seat__gt=0)
-    else:
+    elif require_seat is not None:
         items = items.filter(requires_seat=0)
 
     if filter_items:
@@ -427,14 +427,38 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
             self.request.event.cache.set('vouchers_exist', vouchers_exist)
         context['show_vouchers'] = context['vouchers_exist'] = vouchers_exist
 
+        context['ev'] = self.subevent or self.request.event
+        context['subevent'] = self.subevent
+
+        context['allow_waitinglist'] = self.request.event.settings.waiting_list_enabled and context['ev'].presale_is_running
+
         if not self.request.event.has_subevents or self.subevent:
             # Fetch all items
             items, display_add_to_cart = get_grouped_items(
                 self.request.event, self.subevent,
                 filter_items=self.request.GET.getlist('item'),
                 filter_categories=self.request.GET.getlist('category'),
+                require_seat=None,
                 channel=self.request.sales_channel.identifier
             )
+
+            context['waitinglist_seated'] = False
+            if context['allow_waitinglist']:
+                for i in items:
+                    if not i.allow_waitinglist or not i.requires_seat:
+                        continue
+
+                    if i.has_variations:
+                        for v in i.available_variations:
+                            if v.cached_availability[0] != Quota.AVAILABILITY_OK:
+                                context['waitinglist_seated'] = True
+                                break
+                    else:
+                        if i.cached_availability[0] != Quota.AVAILABILITY_OK:
+                            context['waitinglist_seated'] = True
+                            break
+
+            items = [i for i in items if not i.requires_seat]
             context['itemnum'] = len(items)
             context['allfree'] = all(
                 item.display_price.gross == Decimal('0.00') for item in items if not item.has_variations
@@ -450,11 +474,8 @@ class EventIndex(EventViewMixin, EventListMixin, CartMixin, TemplateView):
             context['items_by_category'] = item_group_by_category(items)
             context['display_add_to_cart'] = display_add_to_cart
 
-        context['ev'] = self.subevent or self.request.event
-        context['subevent'] = self.subevent
         context['cart'] = self.get_cart()
         context['has_addon_choices'] = any(cp.has_addon_choices for cp in get_cart(self.request))
-        context['allow_waitinglist'] = self.request.event.settings.waiting_list_enabled and context['ev'].presale_is_running
 
         if self.subevent:
             context['frontpage_text'] = str(self.subevent.frontpage_text)

src/pretix/presale/views/waiting.py

@@ -19,21 +19,24 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
+from datetime import timedelta
+
 from django.conf import settings
 from django.contrib import messages
+from django.db import transaction
 from django.shortcuts import get_object_or_404, redirect, render
 from django.utils.decorators import method_decorator
-from django.utils.functional import cached_property
+from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
-from django.views.generic import FormView
+from django.views.generic import FormView, TemplateView
 
-from pretix.base.models.event import SubEvent
+from pretix.base.models import Quota, SubEvent
 from pretix.base.templatetags.urlreplace import url_replace
 from pretix.multidomain.urlreverse import eventreverse
 from pretix.presale.views import EventViewMixin
 
 from ...base.i18n import get_language_without_region
-from ...base.models import Item, ItemVariation, WaitingListEntry
+from ...base.models import Voucher, WaitingListEntry
 from ..forms.waitinglist import WaitingListForm
 from . import allow_frame_if_namespaced
 
@@ -47,17 +50,23 @@ class WaitingView(EventViewMixin, FormView):
         kwargs = super().get_form_kwargs()
         kwargs['event'] = self.request.event
         kwargs['instance'] = WaitingListEntry(
-            item=self.item_and_variation[0], variation=self.item_and_variation[1],
             event=self.request.event, locale=get_language_without_region(),
             subevent=self.subevent
         )
+        kwargs['channel'] = self.request.sales_channel.identifier
+        kwargs.setdefault('initial', {})
+        if 'var' in self.request.GET:
+            kwargs['initial']['itemvar'] = f'{self.request.GET.get("item")}-{self.request.GET.get("var")}'
+        else:
+            kwargs['initial']['itemvar'] = self.request.GET.get("item")
+        if getattr(self.request, 'customer', None):
+            kwargs['initial']['email'] = self.request.customer.email
         return kwargs
 
     def get_context_data(self, **kwargs):
         ctx = super().get_context_data(**kwargs)
         ctx['event'] = self.request.event
         ctx['subevent'] = self.subevent
-        ctx['item'], ctx['variation'] = self.item_and_variation
         return ctx
 
     def get(self, request, *args, **kwargs):
@@ -77,20 +86,6 @@ class WaitingView(EventViewMixin, FormView):
 
         return super().get(request, *args, **kwargs)
 
-    @cached_property
-    def item_and_variation(self):
-        try:
-            item = self.request.event.items.get(pk=self.request.GET.get('item'))
-            if 'var' in self.request.GET:
-                var = item.variations.get(pk=self.request.GET['var'])
-            elif item.has_variations:
-                return None
-            else:
-                var = None
-            return item, var
-        except (Item.DoesNotExist, ItemVariation.DoesNotExist, ValueError):
-            return None
-
     def dispatch(self, request, *args, **kwargs):
         self.request = request
 
@@ -106,14 +101,6 @@ class WaitingView(EventViewMixin, FormView):
             messages.error(request, _("The presale for this event has not yet started."))
             return redirect(self.get_index_url())
 
-        if not self.item_and_variation:
-            messages.error(request, _("We could not identify the product you selected."))
-            return redirect(self.get_index_url())
-
-        if not self.item_and_variation[0].allow_waitinglist:
-            messages.error(request, _("The waiting list is disabled for this product."))
-            return redirect(self.get_index_url())
-
         self.subevent = None
         if request.event.has_subevents:
             if 'subevent' in request.GET:
@@ -127,11 +114,11 @@ class WaitingView(EventViewMixin, FormView):
 
     def form_valid(self, form):
         availability = (
-            self.item_and_variation[1].check_quotas(count_waitinglist=True, subevent=self.subevent)
-            if self.item_and_variation[1]
-            else self.item_and_variation[0].check_quotas(count_waitinglist=True, subevent=self.subevent)
+            form.instance.variation.check_quotas(count_waitinglist=True, subevent=self.subevent)
+            if form.instance.variation
+            else form.instance.item.check_quotas(count_waitinglist=True, subevent=self.subevent)
         )
-        if availability[0] == 100:
+        if availability[0] == Quota.AVAILABILITY_OK:
             messages.error(self.request, _("You cannot add yourself to the waiting list as this product is currently "
                                            "available."))
             return redirect(self.get_index_url())
@@ -143,3 +130,43 @@ class WaitingView(EventViewMixin, FormView):
 
     def get_success_url(self):
         return self.get_index_url()
+
+
+@method_decorator(allow_frame_if_namespaced, 'dispatch')
+class WaitingRemoveView(EventViewMixin, TemplateView):
+    template_name = 'pretixpresale/event/waitinglist_remove.html'
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['event'] = self.request.event
+        ctx['voucher'] = self.voucher
+        return ctx
+
+    def dispatch(self, request, *args, **kwargs):
+        self.request = request
+
+        try:
+            self.voucher = self.request.event.vouchers.get(
+                code=request.GET.get("voucher", ""),
+                waitinglistentries__isnull=False,
+            )
+        except Voucher.DoesNotExist:
+            messages.error(request, _("We could not find you on our waiting list."))
+            return redirect(self.get_index_url())
+
+        if not self.voucher.is_active():
+            messages.error(request, _("Your waiting list spot is no longer valid or already used. There's nothing more to do here."))
+            return redirect(self.get_index_url())
+
+        return super().dispatch(request, *args, **kwargs)
+
+    @transaction.atomic()
+    def post(self, request, *args, **kwargs):
+        self.voucher.valid_until = now() - timedelta(seconds=1)
+        self.voucher.save(update_fields=['valid_until'])
+        self.voucher.log_action('pretix.voucher.expired.waitinglist')
+        messages.success(request, _("Thank you very much! We will assign your spot on the waiting list to someone else."))
+        return redirect(self.get_index_url())
+
+    def get_success_url(self):
+        return self.get_index_url()