Fix #526 -- Add a webhook system (#1073)

- [x] Data model
- [x] UI
- [x] Fire hooks
- [x] Unit tests
- [x] Display logs
- [x] API to modify hooks
- [x] Documentation
- [x] More hooks!

src/pretix/api/__init__.py

@@ -5,5 +5,8 @@ class PretixApiConfig(AppConfig):
     name = 'pretix.api'
     label = 'pretixapi'
 
+    def ready(self):
+        from . import signals, webhooks  # noqa
+
 
 default_app_config = 'pretix.api.PretixApiConfig'

src/pretix/api/migrations/0003_webhook_webhookcall_webhookeventlistener.py

@@ -0,0 +1,79 @@
+# Generated by Django 2.1.1 on 2018-11-07 10:46
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0102_auto_20181017_0024'),
+        ('pretixapi', '0002_auto_20180604_1120'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='WebHook',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('enabled', models.BooleanField(default=True, verbose_name='Enable webhook')),
+                ('target_url', models.URLField(verbose_name='Target URL')),
+                ('all_events', models.BooleanField(default=False, verbose_name='All events (including newly created ones)')),
+                ('limit_events', models.ManyToManyField(blank=True, to='pretixbase.Event', verbose_name='Limit to events')),
+                ('organizer', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='pretixbase.Organizer')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='WebHookCall',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('datetime', models.DateTimeField(auto_now_add=True)),
+                ('target_url', models.URLField()),
+                ('is_retry', models.BooleanField(default=False)),
+                ('execution_time', models.FloatField(null=True)),
+                ('return_code', models.PositiveIntegerField(default=0)),
+                ('payload', models.TextField()),
+                ('response_body', models.TextField()),
+                ('webhook', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='pretixapi.WebHook')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='WebHookEventListener',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('action_type', models.CharField(max_length=255)),
+                ('webhook', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='pretixapi.WebHook')),
+            ],
+        ),
+        migrations.AddField(
+            model_name='webhookcall',
+            name='success',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AlterField(
+            model_name='webhook',
+            name='all_events',
+            field=models.BooleanField(default=True, verbose_name='All events (including newly created ones)'),
+        ),
+        migrations.AlterField(
+            model_name='webhook',
+            name='organizer',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='webhooks', to='pretixbase.Organizer'),
+        ),
+        migrations.AlterField(
+            model_name='webhookcall',
+            name='webhook',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='calls', to='pretixapi.WebHook'),
+        ),
+        migrations.AlterField(
+            model_name='webhookeventlistener',
+            name='webhook',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='listeners', to='pretixapi.WebHook'),
+        ),
+        migrations.AddField(
+            model_name='webhookcall',
+            name='action_type',
+            field=models.CharField(default='', max_length=255),
+            preserve_default=False,
+        ),
+    ]

src/pretix/api/models.py

@@ -68,3 +68,41 @@ class OAuthRefreshToken(AbstractRefreshToken):
         OAuthAccessToken, on_delete=models.SET_NULL, blank=True, null=True,
         related_name="refresh_token"
     )
+
+
+class WebHook(models.Model):
+    organizer = models.ForeignKey('pretixbase.Organizer', on_delete=models.CASCADE, related_name='webhooks')
+    enabled = models.BooleanField(default=True, verbose_name=_("Enable webhook"))
+    target_url = models.URLField(verbose_name=_("Target URL"))
+    all_events = models.BooleanField(default=True, verbose_name=_("All events (including newly created ones)"))
+    limit_events = models.ManyToManyField('pretixbase.Event', verbose_name=_("Limit to events"), blank=True)
+
+    @property
+    def action_types(self):
+        return [
+            l.action_type for l in self.listeners.all()
+        ]
+
+
+class WebHookEventListener(models.Model):
+    webhook = models.ForeignKey('WebHook', on_delete=models.CASCADE, related_name='listeners')
+    action_type = models.CharField(max_length=255)
+
+    class Meta:
+        ordering = ("action_type",)
+
+
+class WebHookCall(models.Model):
+    webhook = models.ForeignKey('WebHook', on_delete=models.CASCADE, related_name='calls')
+    datetime = models.DateTimeField(auto_now_add=True)
+    target_url = models.URLField()
+    action_type = models.CharField(max_length=255)
+    is_retry = models.BooleanField(default=False)
+    execution_time = models.FloatField(null=True)
+    return_code = models.PositiveIntegerField(default=0)
+    success = models.BooleanField(default=False)
+    payload = models.TextField()
+    response_body = models.TextField()
+
+    class Meta:
+        ordering = ("-datetime",)

src/pretix/api/serializers/webhooks.py

@@ -0,0 +1,71 @@
+from django.core.exceptions import ValidationError
+from rest_framework import serializers
+
+from pretix.api.models import WebHook
+from pretix.api.serializers.i18n import I18nAwareModelSerializer
+from pretix.api.webhooks import get_all_webhook_events
+from pretix.base.models import Event
+
+
+class EventRelatedField(serializers.SlugRelatedField):
+    def get_queryset(self):
+        return self.context['organizer'].events.all()
+
+
+class ActionTypesField(serializers.Field):
+    def to_representation(self, instance: WebHook):
+        return instance.action_types
+
+    def to_internal_value(self, data):
+        types = get_all_webhook_events()
+        for d in data:
+            if d not in types:
+                raise ValidationError('Invalid action type "%s".' % d)
+        return {'action_types': data}
+
+
+class WebHookSerializer(I18nAwareModelSerializer):
+    limit_events = EventRelatedField(
+        slug_field='slug',
+        queryset=Event.objects.none(),
+        many=True
+    )
+    action_types = ActionTypesField(source='*')
+
+    class Meta:
+        model = WebHook
+        fields = ('id', 'enabled', 'target_url', 'all_events', 'limit_events', 'action_types')
+
+    def validate(self, data):
+        data = super().validate(data)
+
+        full_data = self.to_internal_value(self.to_representation(self.instance)) if self.instance else {}
+        full_data.update(data)
+
+        for event in full_data.get('limit_events'):
+            if self.context['organizer'] != event.organizer:
+                raise ValidationError('One or more events do not belong to this organizer.')
+
+        if full_data.get('limit_events') and full_data.get('all_events'):
+            raise ValidationError('You can set either limit_events or all_events.')
+
+        return data
+
+    def create(self, validated_data):
+        action_types = validated_data.pop('action_types')
+        inst = super().create(validated_data)
+        for l in action_types:
+            inst.listeners.create(action_type=l)
+        return inst
+
+    def update(self, instance, validated_data):
+        action_types = validated_data.pop('action_types', None)
+        instance = super().update(instance, validated_data)
+        if action_types is not None:
+            current_listeners = set(instance.listeners.values_list('action_type', flat=True))
+            new_listeners = set(action_types)
+            for l in current_listeners - new_listeners:
+                instance.listeners.filter(action_type=l).delete()
+            for l in new_listeners - current_listeners:
+                instance.listeners.create(action_type=l)
+        return instance

src/pretix/api/signals.py

@@ -0,0 +1,21 @@
+from datetime import timedelta
+
+from django.dispatch import Signal, receiver
+from django.utils.timezone import now
+
+from pretix.api.models import WebHookCall
+from pretix.base.signals import periodic_task
+
+register_webhook_events = Signal(
+    providing_args=[]
+)
+"""
+This signal is sent out to get all known webhook events. Receivers should return an
+instance of a subclass of pretix.api.webhooks.WebhookEvent or a list of such
+instances.
+"""
+
+
+@receiver(periodic_task)
+def cleanup_webhook_logs(sender, **kwargs):
+    WebHookCall.objects.filter(datetime__lte=now() - timedelta(days=30)).delete()

src/pretix/api/urls.py

@@ -8,7 +8,7 @@ from pretix.api.views import cart
 
 from .views import (
     checkin, device, event, item, oauth, order, organizer, voucher,
-    waitinglist,
+    waitinglist, webhooks,
 )
 
 router = routers.DefaultRouter()
@@ -17,6 +17,7 @@ router.register(r'organizers', organizer.OrganizerViewSet)
 orga_router = routers.DefaultRouter()
 orga_router.register(r'events', event.EventViewSet)
 orga_router.register(r'subevents', event.SubEventViewSet)
+orga_router.register(r'webhooks', webhooks.WebHookViewSet)
 
 event_router = routers.DefaultRouter()
 event_router.register(r'subevents', event.SubEventViewSet)

src/pretix/api/views/checkin.py

@@ -244,7 +244,9 @@ class CheckinListPositionViewSet(viewsets.ReadOnlyModelViewSet):
                 ignore_unpaid=ignore_unpaid,
                 nonce=nonce,
                 datetime=dt,
-                questions_supported=self.request.data.get('questions_supported', True)
+                questions_supported=self.request.data.get('questions_supported', True),
+                user=self.request.user,
+                auth=self.request.auth,
             )
         except RequiredQuestionsError as e:
             return Response({

src/pretix/api/views/webhooks.py

@@ -0,0 +1,49 @@
+from rest_framework import viewsets
+
+from pretix.api.models import WebHook
+from pretix.api.serializers.webhooks import WebHookSerializer
+from pretix.helpers.dicts import merge_dicts
+
+
+class WebHookViewSet(viewsets.ModelViewSet):
+    serializer_class = WebHookSerializer
+    queryset = WebHook.objects.none()
+    permission = 'can_change_organizer_settings'
+    write_permission = 'can_change_organizer_settings'
+
+    def get_queryset(self):
+        return self.request.organizer.webhooks.prefetch_related('listeners')
+
+    def get_serializer_context(self):
+        ctx = super().get_serializer_context()
+        ctx['organizer'] = self.request.organizer
+        return ctx
+
+    def perform_create(self, serializer):
+        inst = serializer.save(organizer=self.request.organizer)
+        self.request.organizer.log_action(
+            'pretix.webhook.created',
+            user=self.request.user,
+            auth=self.request.auth,
+            data=merge_dicts(self.request.data, {'id': inst.pk})
+        )
+
+    def perform_update(self, serializer):
+        inst = serializer.save(organizer=self.request.organizer)
+        self.request.organizer.log_action(
+            'pretix.webhook.changed',
+            user=self.request.user,
+            auth=self.request.auth,
+            data=merge_dicts(self.request.data, {'id': serializer.instance.pk})
+        )
+        return inst
+
+    def perform_destroy(self, instance):
+        self.request.organizer.log_action(
+            'pretix.webhook.changed',
+            user=self.request.user,
+            auth=self.request.auth,
+            data={'id': instance.pk, 'enabled': False}
+        )
+        instance.enabled = False
+        instance.save(update_fields=['enabled'])

src/pretix/api/webhooks.py

@@ -0,0 +1,252 @@
+import json
+import logging
+import time
+from collections import OrderedDict
+
+import requests
+from celery.exceptions import MaxRetriesExceededError
+from django.db.models import Exists, OuterRef, Q
+from django.dispatch import receiver
+from django.utils.translation import ugettext_lazy as _
+from requests import RequestException
+
+from pretix.api.models import WebHook, WebHookCall, WebHookEventListener
+from pretix.api.signals import register_webhook_events
+from pretix.base.models import LogEntry
+from pretix.base.services.tasks import ProfiledTask, TransactionAwareTask
+from pretix.celery_app import app
+
+logger = logging.getLogger(__name__)
+_ALL_EVENTS = None
+
+
+class WebhookEvent:
+    def __init__(self):
+        pass
+
+    def __repr__(self):
+        return '<WebhookEvent: {}>'.format(self.action_type)
+
+    @property
+    def action_type(self) -> str:
+        """
+        The action_type string that this notification handles, for example
+        ``"pretix.event.order.paid"``. Only one notification type should be registered
+        per action type.
+        """
+        raise NotImplementedError()  # NOQA
+
+    @property
+    def verbose_name(self) -> str:
+        """
+        A human-readable name of this notification type.
+        """
+        raise NotImplementedError()  # NOQA
+
+    def build_payload(self, logentry: LogEntry) -> dict:
+        """
+        This is the main function that you should override. It is supposed to turn a log entry
+        object into a dictionary that can be used as the webhook payload.
+        """
+        raise NotImplementedError()  # NOQA
+
+
+def get_all_webhook_events():
+    global _ALL_EVENTS
+
+    if _ALL_EVENTS:
+        return _ALL_EVENTS
+
+    types = OrderedDict()
+    for recv, ret in register_webhook_events.send(None):
+        if isinstance(ret, (list, tuple)):
+            for r in ret:
+                types[r.action_type] = r
+        else:
+            types[ret.action_type] = ret
+    _ALL_EVENTS = types
+    return types
+
+
+class ParametrizedOrderWebhookEvent(WebhookEvent):
+    def __init__(self, action_type, verbose_name):
+        self._action_type = action_type
+        self._verbose_name = verbose_name
+        super().__init__()
+
+    @property
+    def action_type(self):
+        return self._action_type
+
+    @property
+    def verbose_name(self):
+        return self._verbose_name
+
+    def build_payload(self, logentry: LogEntry):
+        order = logentry.content_object
+
+        return {
+            'notification_id': logentry.pk,
+            'organizer': order.event.organizer.slug,
+            'event': order.event.slug,
+            'code': order.code,
+            'action': logentry.action_type,
+        }
+
+
+class ParametrizedOrderPositionWebhookEvent(ParametrizedOrderWebhookEvent):
+
+    def build_payload(self, logentry: LogEntry):
+        d = super().build_payload(logentry)
+        d['orderposition_id'] = logentry.parsed_data.get('position')
+        d['orderposition_positionid'] = logentry.parsed_data.get('positionid')
+        d['checkin_list'] = logentry.parsed_data.get('list')
+        d['first_checkin'] = logentry.parsed_data.get('first_checkin')
+
+
+@receiver(register_webhook_events, dispatch_uid="base_register_default_webhook_events")
+def register_default_webhook_events(sender, **kwargs):
+    return (
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.placed',
+            _('New order placed'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.paid',
+            _('Order marked as paid'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.canceled',
+            _('Order canceled'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.expired',
+            _('Order expired'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.modified',
+            _('Order information changed'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.contact.changed',
+            _('Order contact address changed'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.changed.*',
+            _('Order changed'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.refund.created.externally',
+            _('External refund of payment'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.refunded',
+            _('Order refunded'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.approved',
+            _('Order approved'),
+        ),
+        ParametrizedOrderWebhookEvent(
+            'pretix.event.order.denied',
+            _('Order denied'),
+        ),
+        ParametrizedOrderPositionWebhookEvent(
+            'pretix.event.checkin',
+            _('Ticket checked in'),
+        ),
+        ParametrizedOrderPositionWebhookEvent(
+            'pretix.event.checkin.reverted',
+            _('Ticket check-in reverted'),
+        ),
+    )
+
+
+@app.task(base=TransactionAwareTask)
+def notify_webhooks(logentry_id: int):
+    logentry = LogEntry.all.get(id=logentry_id)
+
+    if not logentry.organizer:
+        return  # We need to know the organizer
+
+    types = get_all_webhook_events()
+    notification_type = None
+    typepath = logentry.action_type
+    while not notification_type and '.' in typepath:
+        notification_type = types.get(typepath + ('.*' if typepath != logentry.action_type else ''))
+        typepath = typepath.rsplit('.', 1)[0]
+
+    if not notification_type:
+        return  # Ignore, no webhooks for this event type
+
+    # All webhooks that registered for this notification
+    event_listener = WebHookEventListener.objects.filter(
+        webhook=OuterRef('pk'),
+        action_type=notification_type.action_type
+    )
+
+    webhooks = WebHook.objects.annotate(has_el=Exists(event_listener)).filter(
+        organizer=logentry.organizer,
+        has_el=True,
+        enabled=True
+    )
+    if logentry.event_id:
+        webhooks = webhooks.filter(
+            Q(all_events=True) | Q(limit_events__pk=logentry.event_id)
+        )
+
+    for wh in webhooks:
+        send_webhook.apply_async(args=(logentry_id, notification_type.action_type, wh.pk))
+
+
+@app.task(base=ProfiledTask, bind=True, max_retries=9)
+def send_webhook(self, logentry_id: int, action_type: str, webhook_id: int):
+    # 9 retries with 2**(2*x) timing is roughly 72 hours
+    logentry = LogEntry.all.get(id=logentry_id)
+    webhook = WebHook.objects.get(id=webhook_id)
+
+    types = get_all_webhook_events()
+    event_type = types.get(action_type)
+    if not event_type or not webhook.enabled:
+        return  # Ignore, e.g. plugin not installed
+
+    payload = event_type.build_payload(logentry)
+    t = time.time()
+
+    try:
+        try:
+            resp = requests.post(
+                webhook.target_url,
+                json=payload,
+                allow_redirects=False
+            )
+            WebHookCall.objects.create(
+                webhook=webhook,
+                action_type=logentry.action_type,
+                target_url=webhook.target_url,
+                is_retry=self.request.retries > 0,
+                execution_time=time.time() - t,
+                return_code=resp.status_code,
+                payload=json.dumps(payload),
+                response_body=resp.text[:1024 * 1024],
+                success=200 <= resp.status_code <= 299
+            )
+            if resp.status_code == 410:
+                webhook.enabled = False
+                webhook.save()
+            elif resp.status_code > 299:
+                raise self.retry(countdown=2 ** (self.request.retries * 2))
+        except RequestException as e:
+            WebHookCall.objects.create(
+                webhook=webhook,
+                action_type=logentry.action_type,
+                target_url=webhook.target_url,
+                is_retry=self.request.retries > 0,
+                execution_time=time.time() - t,
+                return_code=0,
+                payload=json.dumps(payload),
+                response_body=str(e)[:1024 * 1024]
+            )
+            raise self.retry(countdown=2 ** (self.request.retries * 2))
+    except MaxRetriesExceededError:
+        pass

src/pretix/base/models/base.py

@@ -53,6 +53,7 @@ class LoggingMixin:
         from .organizer import TeamAPIToken
         from ..notifications import get_all_notification_types
         from ..services.notifications import notify
+        from pretix.api.webhooks import get_all_webhook_events, notify_webhooks
 
         event = None
         if isinstance(self, Event):
@@ -80,8 +81,21 @@ class LoggingMixin:
         if save:
             logentry.save()
 
-            if action in get_all_notification_types():
+            no_types = get_all_notification_types()
+            wh_types = get_all_webhook_events()
+
+            no_type = None
+            wh_type = None
+            typepath = logentry.action_type
+            while (not no_type or not wh_types) and '.' in typepath:
+                wh_type = wh_type or wh_types.get(typepath + ('.*' if typepath != logentry.action_type else ''))
+                no_type = no_type or no_types.get(typepath + ('.*' if typepath != logentry.action_type else ''))
+                typepath = typepath.rsplit('.', 1)[0]
+
+            if no_type:
                 notify.apply_async(args=(logentry.pk,))
+            if wh_type:
+                notify_webhooks.apply_async(args=(logentry.pk,))
         return logentry
 
 

src/pretix/base/models/log.py

@@ -63,6 +63,16 @@ class LogEntry(models.Model):
                 return response
         return self.action_type
 
+    @cached_property
+    def organizer(self):
+        if self.event:
+            return self.event.organizer
+        elif hasattr(self.content_object, 'event'):
+            return self.content_object.event.organizer
+        elif hasattr(self.content_object, 'organizer'):
+            return self.content_object.organizer
+        return None
+
     @cached_property
     def display_object(self):
         from . import Order, Voucher, Quota, Item, ItemCategory, Question, Event, TaxRule, SubEvent

src/pretix/base/notifications.py

@@ -225,7 +225,7 @@ def register_default_notification_types(sender, **kwargs):
         ),
         ParametrizedOrderNotificationType(
             sender,
-            'pretix.event.order.changed',
+            'pretix.event.order.changed.*',
             _('Order changed'),
             _('Order {order.code} has been changed.')
         ),

src/pretix/base/services/checkin.py

@@ -59,7 +59,8 @@ def _save_answers(op, answers, given_answers):
 
 @transaction.atomic
 def perform_checkin(op: OrderPosition, clist: CheckinList, given_answers: dict, force=False,
-                    ignore_unpaid=False, nonce=None, datetime=None, questions_supported=True):
+                    ignore_unpaid=False, nonce=None, datetime=None, questions_supported=True,
+                    user=None, auth=None):
     """
     Create a checkin for this particular order position and check-in list. Fails with CheckInError if the check in is
     not valid at this time.
@@ -133,7 +134,7 @@ def perform_checkin(op: OrderPosition, clist: CheckinList, given_answers: dict,
                 'forced': op.order.status != Order.STATUS_PAID,
                 'datetime': dt,
                 'list': clist.pk
-            })
+            }, user=user, auth=auth)
     else:
         if not force:
             raise CheckInError(
@@ -147,4 +148,4 @@ def perform_checkin(op: OrderPosition, clist: CheckinList, given_answers: dict,
             'forced': force,
             'datetime': dt,
             'list': clist.pk
-        })
+        }, user=user, auth=auth)

src/pretix/base/services/notifications.py

@@ -17,9 +17,15 @@ def notify(logentry_id: int):
     if not logentry.event:
         return  # Ignore, we only have event-related notifications right now
     types = get_all_notification_types(logentry.event)
-    notification_type = types.get(logentry.action_type)
+
+    notification_type = None
+    typepath = logentry.action_type
+    while not notification_type and '.' in typepath:
+        notification_type = types.get(typepath + ('.*' if typepath != logentry.action_type else ''))
+        typepath = typepath.rsplit('.', 1)[0]
+
     if not notification_type:
-        return  # Ignore, e.g. plugin not active for this event
+        return  # No suitable plugin
 
     # All users that have the permission to get the notification
     users = logentry.event.get_users_with_permission(
@@ -33,7 +39,7 @@ def notify(logentry_id: int):
         (ns.user, ns.method): ns.enabled
         for ns in NotificationSetting.objects.filter(
             event=logentry.event,
-            action_type=logentry.action_type,
+            action_type=notification_type.action_type,
             user__pk__in=users.values_list('pk', flat=True)
         )
     }
@@ -41,7 +47,7 @@ def notify(logentry_id: int):
         (ns.user, ns.method): ns.enabled
         for ns in NotificationSetting.objects.filter(
             event__isnull=True,
-            action_type=logentry.action_type,
+            action_type=notification_type.action_type,
             user__pk__in=users.values_list('pk', flat=True)
         )
     }
@@ -49,20 +55,20 @@ def notify(logentry_id: int):
     for um, enabled in notify_specific.items():
         user, method = um
         if enabled:
-            send_notification.apply_async(args=(logentry_id, user.pk, method))
+            send_notification.apply_async(args=(logentry_id, notification_type.action_type, user.pk, method))
 
     for um, enabled in notify_global.items():
         user, method = um
         if enabled and um not in notify_specific:
-            send_notification.apply_async(args=(logentry_id, user.pk, method))
+            send_notification.apply_async(args=(logentry_id, notification_type.action_type, user.pk, method))
 
 
 @app.task(base=ProfiledTask)
-def send_notification(logentry_id: int, user_id: int, method: str):
+def send_notification(logentry_id: int, action_type: str, user_id: int, method: str):
     logentry = LogEntry.all.get(id=logentry_id)
     user = User.objects.get(id=user_id)
     types = get_all_notification_types(logentry.event)
-    notification_type = types.get(logentry.action_type)
+    notification_type = types.get(action_type)
     if not notification_type:
         return  # Ignore, e.g. plugin not active for this event
 

src/pretix/control/forms/organizer.py

@@ -2,9 +2,12 @@ from django import forms
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.core.validators import RegexValidator
-from django.utils.translation import ugettext_lazy as _
+from django.utils.safestring import mark_safe
+from django.utils.translation import pgettext_lazy, ugettext_lazy as _
 from i18nfield.forms import I18nFormField, I18nTextarea
 
+from pretix.api.models import WebHook
+from pretix.api.webhooks import get_all_webhook_events
 from pretix.base.forms import I18nModelForm, SettingsForm
 from pretix.base.models import Device, Organizer, Team
 from pretix.control.forms import ExtFileField, MultipleLanguagesWidget
@@ -222,3 +225,32 @@ class OrganizerDisplaySettingsForm(SettingsForm):
         self.fields['primary_font'].choices += [
             (a, a) for a in get_fonts()
         ]
+
+
+class WebHookForm(forms.ModelForm):
+    events = forms.MultipleChoiceField(
+        widget=forms.CheckboxSelectMultiple,
+        label=pgettext_lazy('webhooks', 'Event types')
+    )
+
+    def __init__(self, *args, **kwargs):
+        organizer = kwargs.pop('organizer')
+        super().__init__(*args, **kwargs)
+        self.fields['limit_events'].queryset = organizer.events.all()
+        self.fields['events'].choices = [
+            (
+                a.action_type,
+                mark_safe('{} – <code>{}</code>'.format(a.verbose_name, a.action_type))
+            ) for a in get_all_webhook_events().values()
+        ]
+        if self.instance:
+            self.fields['events'].initial = list(self.instance.listeners.values_list('action_type', flat=True))
+
+    class Meta:
+        model = WebHook
+        fields = ['target_url', 'enabled', 'all_events', 'limit_events']
+        widgets = {
+            'limit_events': forms.CheckboxSelectMultiple(attrs={
+                'data-inverse-dependency': '#id_all_events'
+            }),
+        }

src/pretix/control/logdisplay.py

@@ -123,13 +123,13 @@ def _display_checkin(event, logentry):
 
     if data.get('first'):
         if show_dt:
-            return _('Position #{posid} has been scanned at {datetime} for list "{list}".').format(
+            return _('Position #{posid} has been checked in at {datetime} for list "{list}".').format(
                 posid=data.get('positionid'),
                 datetime=dt_formatted,
                 list=checkin_list
             )
         else:
-            return _('Position #{posid} has been scanned for list "{list}".').format(
+            return _('Position #{posid} has been checked in for list "{list}".').format(
                 posid=data.get('positionid'),
                 list=checkin_list
             )
@@ -321,6 +321,7 @@ def pretixcontrol_logentry_display(sender: Event, logentry: LogEntry, **kwargs):
         return _display_checkin(sender, logentry)
 
     if logentry.action_type == 'pretix.control.views.checkin':
+        # deprecated
         dt = dateutil.parser.parse(data.get('datetime'))
         tz = pytz.timezone(sender.settings.timezone)
         dt_formatted = date_format(dt.astimezone(tz), "SHORT_DATETIME_FORMAT")
@@ -344,7 +345,7 @@ def pretixcontrol_logentry_display(sender: Event, logentry: LogEntry, **kwargs):
             list=checkin_list
         )
 
-    if logentry.action_type == 'pretix.control.views.checkin.reverted':
+    if logentry.action_type in ('pretix.control.views.checkin.reverted', 'pretix.event.checkin.reverted'):
         if 'list' in data:
             try:
                 checkin_list = sender.checkin_lists.get(pk=data.get('list')).name

src/pretix/control/templates/pretixcontrol/organizers/base.html

@@ -46,6 +46,13 @@
                 </a>
             </li>
         {% endif %}
+        {% if 'can_change_organizer_settings' in request.orgapermset %}
+            <li {% if "organizer.webhook" in url_name %}class="active"{% endif %}>
+                <a href="{% url "control:organizer.webhooks" organizer=organizer.slug %}">
+                    {% trans "Webhooks" %}
+                </a>
+            </li>
+        {% endif %}
         {% for nav in nav_organizer %}
             <li {% if nav.active %}class="active"{% endif %}>
                 <a href="{{ nav.url }}">

src/pretix/control/templates/pretixcontrol/organizers/webhook_edit.html

@@ -0,0 +1,24 @@
+{% extends "pretixcontrol/organizers/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% block inner %}
+    {% if webhook %}
+        <legend>{% trans "Modify webhook" %}</legend>
+    {% else %}
+        <legend>{% trans "Create a new webhook" %}</legend>
+    {% endif %}
+    <form class="form-horizontal" action="" method="post">
+        {% csrf_token %}
+        {% bootstrap_form_errors form %}
+        {% bootstrap_field form.target_url layout="control" %}
+        {% bootstrap_field form.enabled layout="control" %}
+        {% bootstrap_field form.events layout="control" %}
+        {% bootstrap_field form.all_events layout="control" %}
+        {% bootstrap_field form.limit_events layout="control" %}
+        <div class="form-group submit-group">
+            <button type="submit" class="btn btn-primary btn-save">
+                {% trans "Save" %}
+            </button>
+        </div>
+    </form>
+{% endblock %}

src/pretix/control/templates/pretixcontrol/organizers/webhook_logs.html

@@ -0,0 +1,67 @@
+{% extends "pretixcontrol/organizers/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% block inner %}
+    <legend>{% blocktrans with url=webhook.target_url %}Logs for webhook {{ url }}{% endblocktrans %}</legend>
+    <p>
+        {% trans "This page shows all calls to your webhook in the past 30 days." %}
+    </p>
+    {% for c in calls %}
+        <details class="panel panel-default">
+            <summary class="panel-heading">
+                <div class="row">
+                    <div class="col-md-4 col-sm-12 col-xs-12">
+                        {% if c.is_retry %}
+                            <span class="fa fa-repeat fa-fw" data-toggle="tooltip" title="{% trans "This webhook was retried since it previously failed." %}"></span>
+                        {% else %}
+                            <span class="fa fa-clock-o fa-fw"></span>
+                        {% endif %}
+                        {{ c.datetime|date:"SHORT_DATETIME_FORMAT" }}
+                    </div>
+                    <div class="col-md-4 col-sm-12 col-xs-12">
+                        <span class="fa fa-tag fa-fw"></span>
+                        {{ c.action_type }}
+                    </div>
+                    <div class="col-md-2 col-sm-2 col-xs-4">
+                        <span class="fa fa-hourglass fa-fw"></span>
+                        {{ c.execution_time|floatformat:2 }}s
+                    </div>
+                    <div class="col-md-2 col-xs-8 text-right">
+                        {% if c.success %}
+                            <span class="label label-success">
+                                <span class="fa fa-check-circle fa-fw"></span>
+                                {{ c.return_code }}
+                            </span>
+                        {% else %}
+                            {% if c.return_code %}
+                                <span class="label label-danger">
+                                    <span class="fa fa-warning fa-fw"></span>
+                                    {{ c.return_code }}
+                                </span>
+                            {% else %}
+                                <span class="label label-danger">
+                                    <span class="fa fa-warning fa-fw"></span>
+                                    {% trans "Failed" %}
+                                </span>
+                            {% endif %}
+                        {% endif %}
+                    </div>
+                </div>
+            </summary>
+            <div id="{{ c.pk }}">
+
+                <div class="panel-body">
+                    <strong>{% trans "Request URL" %}</strong>
+                    <pre><code>POST {{ c.target_url }}</code></pre>
+                    <strong>{% trans "Request POST body" %}</strong>
+                    <pre><code>{{ c.payload }}</code></pre>
+                    <strong>{% trans "Response body" %}</strong>
+                    <pre><code>{{ c.response_body }}</code></pre>
+                </div>
+            </div>
+        </details>
+    {% empty %}
+        <div class="alert-info">{% trans "This webhook did not receive any events in the last 30 days." %}</div>
+    {% endfor %}
+    {% include "pretixcontrol/pagination.html" %}
+{% endblock %}

src/pretix/control/templates/pretixcontrol/organizers/webhooks.html

@@ -0,0 +1,78 @@
+{% extends "pretixcontrol/organizers/base.html" %}
+{% load i18n %}
+{% load bootstrap3 %}
+{% block inner %}
+    <legend>
+        {% trans "Webhooks" %}
+    </legend>
+    <p>
+        {% blocktrans trimmed %}
+            This menu allows you to create webhooks to connect pretix to other online services.
+        {% endblocktrans %}
+    </p>
+    {% if webhooks|length == 0 %}
+        <div class="empty-collection">
+            <p>
+                {% blocktrans trimmed %}
+                    You haven't created any webhooks yet.
+                {% endblocktrans %}
+            </p>
+
+            <a href="{% url "control:organizer.webhook.add" organizer=request.organizer.slug %}"
+                    class="btn btn-primary btn-lg"><i class="fa fa-plus"></i> {% trans "Create webhook" %}</a>
+        </div>
+    {% else %}
+        <p>
+            <a href="{% url "control:organizer.webhook.add" organizer=request.organizer.slug %}"
+                    class="btn btn-default"><i class="fa fa-plus"></i> {% trans "Create webhook" %}</a>
+        </p>
+        <div class="table-responsive">
+            <table class="table table-condensed table-hover">
+                <thead>
+                <tr>
+                    <th>{% trans "Target URL" %}</th>
+                    <th>{% trans "Events" %}</th>
+                    <th></th>
+                </tr>
+                </thead>
+                <tbody>
+                {% for w in webhooks %}
+                    <tr>
+                        <td>
+                            {% if not w.enabled %}<del>{% endif %}
+                            {{ w.target_url }}
+                            {% if not w.enabled %}</del>{% endif %}
+                        </td>
+                        <td>
+                            {% if w.all_events %}
+                                {% trans "All" %}
+                            {% else %}
+                                <ul>
+                                    {% for e in w.limit_events.all %}
+                                        <li>
+                                            <a href="{% url "control:event.index" organizer=request.organizer.slug event=e.slug %}">
+                                                {{ e }}
+                                            </a>
+                                        </li>
+                                    {% endfor %}
+                                </ul>
+                            {% endif %}
+                        </td>
+                        <td class="text-right">
+                            <a href="{% url "control:organizer.webhook.edit" organizer=request.organizer.slug webhook=w.id %}"
+                                    class="btn btn-default btn-sm" data-toggle="tooltip" title="{% trans "Edit" %}">
+                                <i class="fa fa-edit"></i>
+                            </a>
+                            <a href="{% url "control:organizer.webhook.logs" organizer=request.organizer.slug webhook=w.id %}"
+                                    class="btn btn-default btn-sm" data-toggle="tooltip" title="{% trans "Logs" %}">
+                                <i class="fa fa-list"></i>
+                            </a>
+                        </td>
+                    </tr>
+                {% endfor %}
+                </tbody>
+            </table>
+        </div>
+        {% include "pretixcontrol/pagination.html" %}
+    {% endif %}
+{% endblock %}

src/pretix/control/urls.py

@@ -71,6 +71,13 @@ urlpatterns = [
     url(r'^organizer/(?P<organizer>[^/]+)/delete$', organizer.OrganizerDelete.as_view(), name='organizer.delete'),
     url(r'^organizer/(?P<organizer>[^/]+)/settings/display$', organizer.OrganizerDisplaySettings.as_view(),
         name='organizer.display'),
+    url(r'^organizer/(?P<organizer>[^/]+)/webhooks$', organizer.WebHookListView.as_view(), name='organizer.webhooks'),
+    url(r'^organizer/(?P<organizer>[^/]+)/webhook/add$', organizer.WebHookCreateView.as_view(),
+        name='organizer.webhook.add'),
+    url(r'^organizer/(?P<organizer>[^/]+)/webhook/(?P<webhook>[^/]+)/edit$', organizer.WebHookUpdateView.as_view(),
+        name='organizer.webhook.edit'),
+    url(r'^organizer/(?P<organizer>[^/]+)/webhook/(?P<webhook>[^/]+)/logs$', organizer.WebHookLogsView.as_view(),
+        name='organizer.webhook.logs'),
     url(r'^organizer/(?P<organizer>[^/]+)/devices$', organizer.DeviceListView.as_view(), name='organizer.devices'),
     url(r'^organizer/(?P<organizer>[^/]+)/device/add$', organizer.DeviceCreateView.as_view(),
         name='organizer.device.add'),

src/pretix/control/views/checkin.py

@@ -94,10 +94,11 @@ class CheckInListShow(EventPermissionRequiredMixin, PaginationMixin, ListView):
             for op in positions:
                 if op.order.status == Order.STATUS_PAID or (self.list.include_pending and op.order.status == Order.STATUS_PENDING):
                     Checkin.objects.filter(position=op, list=self.list).delete()
-                    op.order.log_action('pretix.control.views.checkin.reverted', data={
+                    op.order.log_action('pretix.event.checkin.reverted', data={
                         'position': op.id,
                         'positionid': op.positionid,
-                        'list': self.list.pk
+                        'list': self.list.pk,
+                        'web': True
                     }, user=request.user)
 
             messages.success(request, _('The selected check-ins have been reverted.'))
@@ -108,12 +109,14 @@ class CheckInListShow(EventPermissionRequiredMixin, PaginationMixin, ListView):
                     ci, created = Checkin.objects.get_or_create(position=op, list=self.list, defaults={
                         'datetime': now(),
                     })
-                    op.order.log_action('pretix.control.views.checkin', data={
+                    op.order.log_action('pretix.event.checkin', data={
                         'position': op.id,
                         'positionid': op.positionid,
                         'first': created,
+                        'forced': False,
                         'datetime': now(),
-                        'list': self.list.pk
+                        'list': self.list.pk,
+                        'web': True
                     }, user=request.user)
 
             messages.success(request, _('The selected tickets have been marked as checked in.'))

src/pretix/control/views/organizer.py

@@ -17,6 +17,7 @@ from django.views.generic import (
     CreateView, DeleteView, DetailView, FormView, ListView, UpdateView,
 )
 
+from pretix.api.models import WebHook
 from pretix.base.models import Device, Organizer, Team, TeamInvite, User
 from pretix.base.models.event import EventMetaProperty
 from pretix.base.models.organizer import TeamAPIToken
@@ -25,13 +26,14 @@ from pretix.control.forms.filter import OrganizerFilterForm
 from pretix.control.forms.organizer import (
     DeviceForm, EventMetaPropertyForm, OrganizerDeleteForm,
     OrganizerDisplaySettingsForm, OrganizerForm, OrganizerSettingsForm,
-    OrganizerUpdateForm, TeamForm,
+    OrganizerUpdateForm, TeamForm, WebHookForm,
 )
 from pretix.control.permissions import (
     AdministratorPermissionRequiredMixin, OrganizerPermissionRequiredMixin,
 )
 from pretix.control.signals import nav_organizer
 from pretix.control.views import PaginationMixin
+from pretix.helpers.dicts import merge_dicts
 from pretix.helpers.urls import build_absolute_uri
 from pretix.presale.style import regenerate_organizer_css
 
@@ -761,3 +763,110 @@ class DeviceRevokeView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMixi
         return redirect(reverse('control:organizer.devices', kwargs={
             'organizer': self.request.organizer.slug,
         }))
+
+
+class WebHookListView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMixin, ListView):
+    model = WebHook
+    template_name = 'pretixcontrol/organizers/webhooks.html'
+    permission = 'can_change_organizer_settings'
+    context_object_name = 'webhooks'
+
+    def get_queryset(self):
+        return self.request.organizer.webhooks.prefetch_related('limit_events')
+
+
+class WebHookCreateView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMixin, CreateView):
+    model = WebHook
+    template_name = 'pretixcontrol/organizers/webhook_edit.html'
+    permission = 'can_change_organizer_settings'
+    form_class = WebHookForm
+
+    def get_form_kwargs(self):
+        kwargs = super().get_form_kwargs()
+        kwargs['organizer'] = self.request.organizer
+        return kwargs
+
+    def get_success_url(self):
+        return reverse('control:organizer.webhooks', kwargs={
+            'organizer': self.request.organizer.slug,
+        })
+
+    def form_valid(self, form):
+        form.instance.organizer = self.request.organizer
+        ret = super().form_valid(form)
+        self.request.organizer.log_action('pretix.webhook.created', user=self.request.user, data=merge_dicts({
+            k: form.cleaned_data[k] if k != 'limit_events' else [e.id for e in getattr(self.object, k).all()]
+            for k in form.changed_data
+        }, {'id': form.instance.pk}))
+        new_listeners = set(form.cleaned_data['events'])
+        for l in new_listeners:
+            self.object.listeners.create(action_type=l)
+        return ret
+
+    def form_invalid(self, form):
+        messages.error(self.request, _('Your changes could not be saved.'))
+        return super().form_invalid(form)
+
+
+class WebHookUpdateView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMixin, UpdateView):
+    model = WebHook
+    template_name = 'pretixcontrol/organizers/webhook_edit.html'
+    permission = 'can_change_organizer_settings'
+    context_object_name = 'webhook'
+    form_class = WebHookForm
+
+    def get_form_kwargs(self):
+        kwargs = super().get_form_kwargs()
+        kwargs['organizer'] = self.request.organizer
+        return kwargs
+
+    def get_object(self, queryset=None):
+        return get_object_or_404(WebHook, organizer=self.request.organizer, pk=self.kwargs.get('webhook'))
+
+    def get_success_url(self):
+        return reverse('control:organizer.webhooks', kwargs={
+            'organizer': self.request.organizer.slug,
+        })
+
+    def form_valid(self, form):
+        if form.has_changed():
+            self.request.organizer.log_action('pretix.webhook.changed', user=self.request.user, data=merge_dicts({
+                k: form.cleaned_data[k] if k != 'limit_events' else [e.id for e in getattr(self.object, k).all()]
+                for k in form.changed_data
+            }, {'id': form.instance.pk}))
+
+        current_listeners = set(self.object.listeners.values_list('action_type', flat=True))
+        new_listeners = set(form.cleaned_data['events'])
+        for l in current_listeners - new_listeners:
+            self.object.listeners.filter(action_type=l).delete()
+        for l in new_listeners - current_listeners:
+            self.object.listeners.create(action_type=l)
+
+        messages.success(self.request, _('Your changes have been saved.'))
+        return super().form_valid(form)
+
+    def form_invalid(self, form):
+        messages.error(self.request, _('Your changes could not be saved.'))
+        return super().form_invalid(form)
+
+
+class WebHookLogsView(OrganizerDetailViewMixin, OrganizerPermissionRequiredMixin, ListView):
+    model = WebHook
+    template_name = 'pretixcontrol/organizers/webhook_logs.html'
+    permission = 'can_change_organizer_settings'
+    context_object_name = 'calls'
+    paginate_by = 50
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['webhook'] = self.webhook
+        return ctx
+
+    @cached_property
+    def webhook(self):
+        return get_object_or_404(
+            WebHook, organizer=self.request.organizer, pk=self.kwargs.get('webhook')
+        )
+
+    def get_queryset(self):
+        return self.webhook.calls.order_by('-datetime')

src/pretix/control/views/pdf.py

@@ -76,16 +76,16 @@ class BaseEditorView(EventPermissionRequiredMixin, TemplateView):
         return p
 
     def generate(self, p: OrderPosition, override_layout=None, override_background=None):
-        raise NotImplemented
+        raise NotImplementedError()
 
     def get_layout_settings_key(self):
-        raise NotImplemented
+        raise NotImplementedError()
 
     def get_background_settings_key(self):
-        raise NotImplemented
+        raise NotImplementedError()
 
     def get_default_background(self):
-        raise NotImplemented
+        raise NotImplementedError()
 
     def get_current_background(self):
         return (