API: Expose TaxRule.custom_rules

doc/api/resources/taxrules.rst

@@ -20,11 +20,16 @@ internal_name                         string                     An optional nam
 rate                                  decimal (string)           Tax rate in percent
 price_includes_tax                    boolean                    If ``true`` (default), tax is assumed to be included in
                                                                  the specified product price
-eu_reverse_charge                     boolean                    If ``true``, EU reverse charge rules are applied
+eu_reverse_charge                     boolean                    If ``true``, EU reverse charge rules are applied. Will
+                                                                 be ignored if custom rules are set.
 home_country                          string                     Merchant country (required for reverse charge), can be
                                                                  ``null`` or empty string
 keep_gross_if_rate_changes            boolean                    If ``true``, changes of the tax rate based on custom
                                                                  rules keep the gross price constant (default is ``false``)
+custom_rules                          object                     Dynamic rules specification. Each list element
+                                                                 corresponds to one rule that will be processed in order.
+                                                                 The current version of the schema in use can be found
+                                                                 `here`_.
 ===================================== ========================== =======================================================
 
 
@@ -32,6 +37,10 @@ keep_gross_if_rate_changes            boolean                    If ``true``, ch
 
     The ``internal_name`` and ``keep_gross_if_rate_changes`` attributes have been added.
 
+.. versionchanged:: 2023.6
+
+    The ``custom_rules`` attribute has been added.
+
 Endpoints
 ---------
 
@@ -68,6 +77,7 @@ Endpoints
             "price_includes_tax": true,
             "eu_reverse_charge": false,
             "keep_gross_if_rate_changes": false,
+            "custom_rules": null,
             "home_country": "DE"
           }
         ]
@@ -108,6 +118,7 @@ Endpoints
         "price_includes_tax": true,
         "eu_reverse_charge": false,
         "keep_gross_if_rate_changes": false,
+        "custom_rules": null,
         "home_country": "DE"
       }
 
@@ -156,6 +167,7 @@ Endpoints
         "price_includes_tax": true,
         "eu_reverse_charge": false,
         "keep_gross_if_rate_changes": false,
+        "custom_rules": null,
         "home_country": "DE"
       }
 
@@ -203,6 +215,7 @@ Endpoints
         "price_includes_tax": true,
         "eu_reverse_charge": false,
         "keep_gross_if_rate_changes": false,
+        "custom_rules": null,
         "home_country": "DE"
       }
 
@@ -242,3 +255,5 @@ Endpoints
    :statuscode 204: no error
    :statuscode 401: Authentication failure
    :statuscode 403: The requested organizer/event/rule does not exist **or** you have no permission to change it **or** this tax rule cannot be deleted since it is currently in use.
+
+.. _here: https://github.com/pretix/pretix/blob/master/src/pretix/static/schema/tax-rules-custom.schema.json

src/pretix/api/serializers/__init__.py

@@ -19,6 +19,8 @@
 # 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/>.
 #
+import json
+
 from rest_framework import serializers
 
 
@@ -46,3 +48,16 @@ class AsymmetricField(serializers.Field):
 
     def run_validation(self, data=serializers.empty):
         return self.write.run_validation(data)
+
+
+class CompatibleJSONField(serializers.JSONField):
+    def to_internal_value(self, data):
+        try:
+            return json.dumps(data)
+        except (TypeError, ValueError):
+            self.fail('invalid')
+
+    def to_representation(self, value):
+        if value:
+            return json.loads(value)
+        return value

src/pretix/api/serializers/event.py

@@ -46,6 +46,7 @@ from rest_framework import serializers
 from rest_framework.fields import ChoiceField, Field
 from rest_framework.relations import SlugRelatedField
 
+from pretix.api.serializers import CompatibleJSONField
 from pretix.api.serializers.i18n import I18nAwareModelSerializer
 from pretix.api.serializers.settings import SettingsSerializer
 from pretix.base.models import Device, Event, TaxRule, TeamAPIToken
@@ -53,6 +54,7 @@ from pretix.base.models.event import SubEvent
 from pretix.base.models.items import (
     ItemMetaProperty, SubEventItem, SubEventItemVariation,
 )
+from pretix.base.models.tax import CustomRulesValidator
 from pretix.base.services.seating import (
     SeatProtected, generate_seats, validate_plan_change,
 )
@@ -650,9 +652,16 @@ class SubEventSerializer(I18nAwareModelSerializer):
 
 
 class TaxRuleSerializer(CountryFieldMixin, I18nAwareModelSerializer):
+    custom_rules = CompatibleJSONField(
+        validators=[CustomRulesValidator()],
+        required=False,
+        allow_null=True,
+    )
+
     class Meta:
         model = TaxRule
-        fields = ('id', 'name', 'rate', 'price_includes_tax', 'eu_reverse_charge', 'home_country', 'internal_name', 'keep_gross_if_rate_changes')
+        fields = ('id', 'name', 'rate', 'price_includes_tax', 'eu_reverse_charge', 'home_country', 'internal_name',
+                  'keep_gross_if_rate_changes', 'custom_rules')
 
 
 class EventSettingsSerializer(SettingsSerializer):

src/pretix/api/serializers/order.py

@@ -19,7 +19,6 @@
 # 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/>.
 #
-import json
 import logging
 import os
 from collections import Counter, defaultdict
@@ -39,6 +38,7 @@ from rest_framework.exceptions import ValidationError
 from rest_framework.relations import SlugRelatedField
 from rest_framework.reverse import reverse
 
+from pretix.api.serializers import CompatibleJSONField
 from pretix.api.serializers.event import SubEventSerializer
 from pretix.api.serializers.i18n import I18nAwareModelSerializer
 from pretix.api.serializers.item import (
@@ -896,19 +896,6 @@ class OrderPositionCreateSerializer(I18nAwareModelSerializer):
         return data
 
 
-class CompatibleJSONField(serializers.JSONField):
-    def to_internal_value(self, data):
-        try:
-            return json.dumps(data)
-        except (TypeError, ValueError):
-            self.fail('invalid')
-
-    def to_representation(self, value):
-        if value:
-            return json.loads(value)
-        return value
-
-
 class WrappedList:
     def __init__(self, data):
         self._data = data

src/pretix/base/models/tax.py

@@ -22,9 +22,12 @@
 import json
 from decimal import Decimal
 
+import jsonschema
+from django.contrib.staticfiles import finders
 from django.core.exceptions import ValidationError
 from django.core.validators import MaxValueValidator, MinValueValidator
 from django.db import models
+from django.utils.deconstruct import deconstructible
 from django.utils.formats import localize
 from django.utils.translation import gettext_lazy as _, pgettext
 from i18nfield.fields import I18nCharField
@@ -135,6 +138,25 @@ def cc_to_vat_prefix(country_code):
     return country_code
 
 
+@deconstructible
+class CustomRulesValidator:
+    def __call__(self, value):
+        if not isinstance(value, dict):
+            try:
+                val = json.loads(value)
+            except ValueError:
+                raise ValidationError(_('Your layout file is not a valid JSON file.'))
+        else:
+            val = value
+        with open(finders.find('schema/tax-rules-custom.schema.json'), 'r') as f:
+            schema = json.loads(f.read())
+        try:
+            jsonschema.validate(val, schema)
+        except jsonschema.ValidationError as e:
+            e = str(e).replace('%', '%%')
+            raise ValidationError(_('Your set of rules is not valid. Error message: {}').format(e))
+
+
 class TaxRule(LoggedModel):
     event = models.ForeignKey('Event', related_name='tax_rules', on_delete=models.CASCADE)
     internal_name = models.CharField(

src/pretix/static/schema/tax-rules-custom.schema.json

@@ -0,0 +1,49 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "Tax rules",
+  "description": "Dynamic taxation rules",
+  "type": "array",
+  "items": {
+    "type": "object",
+    "description": "List of rules, executed in order until one matches",
+    "properties": {
+      "country": {
+        "description": "Country code to match. ZZ = any country, EU = any EU country.",
+        "enum": ["AD", "AE", "AF", "AG", "AI", "AL", "AM", "AO", "AQ", "AR", "AS", "AT", "AU", "AW", "AX", "AZ", "BA", "BB", "BD", "BE", "BF", "BG", "BH", "BI", "BJ", "BL", "BM", "BN", "BO", "BQ", "BR", "BS", "BT", "BV", "BW", "BY", "BZ", "CA", "CC", "CD", "CF", "CG", "CH", "CI", "CK", "CL", "CM", "CN", "CO", "CR", "CU", "CV", "CW", "CX", "CY", "CZ", "DE", "DJ", "DK", "DM", "DO", "DZ", "EC", "EE", "EG", "EH", "ER", "ES", "ET", "EU", "FI", "FJ", "FK", "FM", "FO", "FR", "GA", "GB", "GD", "GE", "GF", "GG", "GH", "GI", "GL", "GM", "GN", "GP", "GQ", "GR", "GS", "GT", "GU", "GW", "GY", "HK", "HM", "HN", "HR", "HT", "HU", "ID", "IE", "IL", "IM", "IN", "IO", "IQ", "IR", "IS", "IT", "JE", "JM", "JO", "JP", "KE", "KG", "KH", "KI", "KM", "KN", "KP", "KR", "KW", "KY", "KZ", "LA", "LB", "LC", "LI", "LK", "LR", "LS", "LT", "LU", "LV", "LY", "MA", "MC", "MD", "ME", "MF", "MG", "MH", "MK", "ML", "MM", "MN", "MO", "MP", "MQ", "MR", "MS", "MT", "MU", "MV", "MW", "MX", "MY", "MZ", "NA", "NC", "NE", "NF", "NG", "NI", "NL", "NO", "NP", "NR", "NU", "NZ", "OM", "PA", "PE", "PF", "PG", "PH", "PK", "PL", "PM", "PN", "PR", "PS", "PT", "PW", "PY", "QA", "RE", "RO", "RS", "RU", "RW", "SA", "SB", "SC", "SD", "SE", "SG", "SH", "SI", "SJ", "SK", "SL", "SM", "SN", "SO", "SR", "SS", "ST", "SV", "SX", "SY", "SZ", "TC", "TD", "TF", "TG", "TH", "TJ", "TK", "TL", "TM", "TN", "TO", "TR", "TT", "TV", "TW", "TZ", "UA", "UG", "UM", "US", "UY", "UZ", "VA", "VC", "VE", "VG", "VI", "VN", "VU", "WF", "WS", "YE", "YT", "ZA", "ZM", "ZW", "ZZ"]
+      },
+      "address_type": {
+        "description": "Type of customer, emtpy = any.",
+        "enum": ["", "individual", "business", "business_vat_id"]
+      },
+      "action": {
+        "description": "Action to take.",
+        "enum": ["vat", "reverse", "no", "block", "require_approval"]
+      },
+      "rate": {
+        "description": "Tax rate in case of action=vat or action=require_approval (or null for default)",
+        "type": ["string", "null"],
+        "pattern": "^[0-9]+(\\.[0-9]+)?$"
+      },
+      "invoice_text": {
+        "description": "Text on invoice (localized)",
+        "type": ["object", "null"],
+        "patternProperties": {
+          "[a-zA-Z-]+": {
+            "type": "string"
+          }
+        },
+        "additionalProperties": false
+      },
+      "ORDER": {
+        "description": "Internal, for backwards-compatibility, will be ignored.",
+        "type": "number"
+      },
+      "DELETE": {
+        "description": "Internal, for backwards-compatibility, will be ignored.",
+        "type": "boolean"
+      }
+    },
+    "required": ["country", "address_type", "action"],
+    "additionalProperties": false
+  }
+}

src/tests/api/test_taxrules.py

@@ -33,7 +33,8 @@ TEST_TAXRULE_RES = {
     'rate': '19.00',
     'price_includes_tax': True,
     'eu_reverse_charge': False,
-    'home_country': ''
+    'home_country': '',
+    'custom_rules': None,
 }
 
 
@@ -84,6 +85,10 @@ def test_rule_update(token_client, organizer, event, taxrule):
         '/api/v1/organizers/{}/events/{}/taxrules/{}/'.format(organizer.slug, event.slug, taxrule.pk),
         {
             "rate": "20.00",
+            "custom_rules": [
+                {"country": "AT", "address_type": "", "action": "vat", "rate": "19.00",
+                 "invoice_text": {"en": "Austrian VAT applies"}}
+            ]
         },
         format='json'
     )
@@ -111,3 +116,20 @@ def test_rule_delete_forbidden(token_client, organizer, event, taxrule):
     )
     assert resp.status_code == 403
     assert event.tax_rules.exists()
+
+
+@pytest.mark.django_db
+def test_rule_update_invalid_rules(token_client, organizer, event, taxrule):
+    resp = token_client.patch(
+        '/api/v1/organizers/{}/events/{}/taxrules/{}/'.format(organizer.slug, event.slug, taxrule.pk),
+        {
+            "custom_rules": [
+                {"foo": "bar"}
+            ]
+        },
+        format='json'
+    )
+    assert resp.status_code == 400
+    assert resp.data["custom_rules"][0].startswith(
+        "Your set of rules is not valid. Error message: 'country' is a required property"
+    )