Enhancement: support custom field values on post document (#10859)

src/documents/serialisers.py

@@ -1749,9 +1749,8 @@ class PostDocumentSerializer(serializers.Serializer):
         max_value=Document.ARCHIVE_SERIAL_NUMBER_MAX,
     )
 
-    custom_fields = serializers.PrimaryKeyRelatedField(
-        many=True,
-        queryset=CustomField.objects.all(),
+    # Accept either a list of custom field ids or a dict mapping id -> value
+    custom_fields = serializers.JSONField(
         label="Custom fields",
         write_only=True,
         required=False,
@@ -1808,11 +1807,60 @@ class PostDocumentSerializer(serializers.Serializer):
             return None
 
     def validate_custom_fields(self, custom_fields):
-        if custom_fields:
-            return [custom_field.id for custom_field in custom_fields]
-        else:
+        if not custom_fields:
             return None
 
+        # Normalize single values to a list
+        if isinstance(custom_fields, int):
+            custom_fields = [custom_fields]
+        if isinstance(custom_fields, dict):
+            custom_field_serializer = CustomFieldInstanceSerializer()
+            normalized = {}
+            for field_id, value in custom_fields.items():
+                try:
+                    field_id_int = int(field_id)
+                except (TypeError, ValueError):
+                    raise serializers.ValidationError(
+                        _("Custom field id must be an integer: %(id)s")
+                        % {"id": field_id},
+                    )
+                try:
+                    field = CustomField.objects.get(id=field_id_int)
+                except CustomField.DoesNotExist:
+                    raise serializers.ValidationError(
+                        _("Custom field with id %(id)s does not exist")
+                        % {"id": field_id_int},
+                    )
+                custom_field_serializer.validate(
+                    {
+                        "field": field,
+                        "value": value,
+                    },
+                )
+                normalized[field_id_int] = value
+            return normalized
+        elif isinstance(custom_fields, list):
+            try:
+                ids = [int(i) for i in custom_fields]
+            except (TypeError, ValueError):
+                raise serializers.ValidationError(
+                    _(
+                        "Custom fields must be a list of integers or an object mapping ids to values.",
+                    ),
+                )
+            if CustomField.objects.filter(id__in=ids).count() != len(set(ids)):
+                raise serializers.ValidationError(
+                    _("Some custom fields don't exist or were specified twice."),
+                )
+            return ids
+        raise serializers.ValidationError(
+            _(
+                "Custom fields must be a list of integers or an object mapping ids to values.",
+            ),
+        )
+
+    # custom_fields_w_values handled via validate_custom_fields
+
     def validate_created(self, created):
         # support datetime format for created for backwards compatibility
         if isinstance(created, datetime):