Add refund details to API

doc/development/api/payment.rst

@@ -126,6 +126,8 @@ The provider class
 
    .. automethod:: api_payment_details
 
+   .. automethod:: api_refund_details
+
    .. automethod:: matching_id
 
    .. automethod:: shred_payment_info

src/pretix/api/serializers/order.py

@@ -553,12 +553,22 @@ class OrderPaymentSerializer(I18nAwareModelSerializer):
                   'details')
 
 
+class RefundDetailsField(serializers.Field):
+    def to_representation(self, value: OrderRefund):
+        pp = value.payment_provider
+        if not pp:
+            return {}
+        return pp.api_refund_details(value)
+
+
 class OrderRefundSerializer(I18nAwareModelSerializer):
     payment = SlugRelatedField(slug_field='local_id', read_only=True)
+    details = RefundDetailsField(source='*', allow_null=True, read_only=True)
 
     class Meta:
         model = OrderRefund
-        fields = ('local_id', 'state', 'source', 'amount', 'payment', 'created', 'execution_date', 'comment', 'provider')
+        fields = ('local_id', 'state', 'source', 'amount', 'payment', 'created', 'execution_date', 'comment', 'provider',
+                  'details')
 
 
 class OrderURLField(serializers.URLField):

src/pretix/base/payment.py

@@ -877,6 +877,15 @@ class BasePaymentProvider:
         """
         return {}
 
+    def api_refund_details(self, refund: OrderRefund):
+        """
+        Will be called to populate the ``details`` parameter of the refund in the REST API.
+
+        :param refund: The refund in question.
+        :return: A serializable dictionary
+        """
+        return {}
+
     def matching_id(self, payment: OrderPayment):
         """
         Will be called to get an ID for matching this payment when comparing pretix records with records of an external
@@ -959,6 +968,9 @@ class BoxOfficeProvider(BasePaymentProvider):
             "payment_data": payment.info_data.get('payment_data', {}),
         }
 
+    def api_refund_details(self, refund: OrderRefund):
+        return self.api_payment_details(refund)
+
     def payment_control_render(self, request, payment) -> str:
         if not payment.info:
             return
@@ -1191,6 +1203,9 @@ class GiftCardPayment(BasePaymentProvider):
             }
         }
 
+    def api_refund_details(self, refund: OrderRefund):
+        return self.api_payment_details(refund)
+
     def payment_partial_refund_supported(self, payment: OrderPayment) -> bool:
         return True