Fix #515 -- Add check-in lists (#693)

* Data model and migration

* Some backwards compatibility

* CRUD for checkin lists

* Show and perform checkins

* Correct numbers in table and dashboard widget

* event creation and cloning

* Allow to link specific exports and pass options per query

* Play with the CSV export

* PDF export

* Collapse exports by default

* Improve PDF exporter

* Addon stuff

* Subevent stuff, pretixdroid tests

* pretixdroid tests

* Add CRUD API

* Test compatibility

* Fix test

* DB-independent sorting behavior

* Add CRUD and coyp tests

* Re-enable pretixdroid plugin

* pretixdroid config

* Tests & fixes

src/pretix/api/serializers/checkin.py

@@ -0,0 +1,37 @@
+from django.utils.translation import ugettext as _
+from rest_framework import serializers
+from rest_framework.exceptions import ValidationError
+
+from pretix.api.serializers.i18n import I18nAwareModelSerializer
+from pretix.base.models import CheckinList
+
+
+class CheckinListSerializer(I18nAwareModelSerializer):
+    checkin_count = serializers.IntegerField(read_only=True)
+    position_count = serializers.IntegerField(read_only=True)
+
+    class Meta:
+        model = CheckinList
+        fields = ('id', 'name', 'all_products', 'limit_products', 'subevent', 'checkin_count', 'position_count')
+
+    def validate(self, data):
+        data = super().validate(data)
+        event = self.context['event']
+
+        full_data = self.to_internal_value(self.to_representation(self.instance)) if self.instance else {}
+        full_data.update(data)
+
+        for item in full_data.get('limit_products'):
+            if event != item.event:
+                raise ValidationError(_('One or more items do not belong to this event.'))
+
+        if event.has_subevents:
+            if not full_data.get('subevent'):
+                raise ValidationError(_('Subevent cannot be null for event series.'))
+            if event != full_data.get('subevent').event:
+                raise ValidationError(_('The subevent does not belong to this event.'))
+        else:
+            if full_data.get('subevent'):
+                raise ValidationError(_('The subevent does not belong to this event.'))
+
+        return data