Reusable media (#3131)

Co-authored-by: Martin Gross <gross@rami.io>

src/pretix/base/media.py

@@ -0,0 +1,116 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# 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 django.db import transaction
+from django.utils.crypto import get_random_string
+from django.utils.translation import gettext_lazy as _
+
+
+class BaseMediaType:
+    medium_created_by_server = False
+    supports_orderposition = False
+    supports_giftcard = False
+
+    @property
+    def identifier(self):
+        raise NotImplementedError()
+
+    @property
+    def verbose_name(self):
+        raise NotImplementedError()
+
+    def generate_identifier(self, organizer):
+        if self.medium_created_by_server:
+            raise NotImplementedError()
+        else:
+            raise ValueError("Media type does not allow to generate identifier")
+
+    def is_active(self, organizer):
+        return organizer.settings.get(f'reusable_media_type_{self.identifier}', as_type=bool, default=False)
+
+    def handle_unknown(self, organizer, identifier, user, auth):
+        pass
+
+    def __str__(self):
+        return str(self.verbose_name)
+
+
+class BarcodePlainMediaType(BaseMediaType):
+    identifier = 'barcode'
+    verbose_name = _('Barcode / QR-Code')
+    medium_created_by_server = True
+    supports_giftcard = False
+    supports_orderposition = True
+
+    def generate_identifier(self, organizer):
+        return get_random_string(
+            length=organizer.settings.reusable_media_type_barcode_identifier_length,
+            # Exclude o,0,1,i to avoid confusion with bad fonts/printers
+            # We use upper case to make collisions with ticket secrets less likely
+            allowed_chars='ABCDEFGHJKLMNPQRSTUVWXYZ23456789'
+        )
+
+
+class NfcUidMediaType(BaseMediaType):
+    identifier = 'nfc_uid'
+    verbose_name = _('NFC UID-based')
+    medium_created_by_server = False
+    supports_giftcard = True
+    supports_orderposition = False
+
+    def handle_unknown(self, organizer, identifier, user, auth):
+        from pretix.base.models import GiftCard, ReusableMedium
+
+        if organizer.settings.get(f'reusable_media_type_{self.identifier}_autocreate_giftcard', as_type=bool):
+            if identifier.startswith("08"):
+                # Don't create gift cards for NFC UIDs that start with 08, which represents NFC cards that issue random
+                # UIDs on every read, so they won't be useful.
+                return
+            with transaction.atomic():
+                gc = GiftCard.objects.create(
+                    issuer=organizer,
+                    expires=organizer.default_gift_card_expiry,
+                    currency=organizer.settings.get(f'reusable_media_type_{self.identifier}_autocreate_giftcard_currency'),
+                )
+                m = ReusableMedium.objects.create(
+                    type=self.identifier,
+                    identifier=identifier,
+                    organizer=organizer,
+                    active=True,
+                    linked_giftcard=gc
+                )
+                m.log_action(
+                    'pretix.reusable_medium.created.auto',
+                    user=user, auth=auth,
+                )
+                gc.log_action(
+                    'pretix.giftcards.created',
+                    user=user, auth=auth,
+                )
+                return m
+
+
+MEDIA_TYPES = {
+    m.identifier: m for m in [
+        BarcodePlainMediaType(),
+        NfcUidMediaType(),
+    ]
+}