Overridde serializers for vocabulary-based fields

src/plone/exportimport/serializers/configure.zcml

@@ -4,4 +4,6 @@
   <adapter factory=".blob.ExportImportSimpleFileFieldSerializer" />
   <adapter factory=".blob.ExportImportSimpleImageFieldSerializer" />
   <adapter factory=".blocks.ExportImportBlocksSerializer" />
+  <adapter factory=".fields.CollectionFieldSerializer" />
+  <adapter factory=".fields.ChoiceFieldSerializer" />
 </configure>

src/plone/exportimport/serializers/fields.py

@@ -0,0 +1,77 @@
+from plone.exportimport.interfaces import IExportImportRequestMarker
+from plone.restapi.serializer.converters import json_compatible
+from zope.component import adapter
+from zope.interface import implementer
+from plone.dexterity.interfaces import IDexterityContent
+from zope.schema.interfaces import IChoice
+from zope.schema.interfaces import ICollection
+from zope.schema.interfaces import IField
+from zope.schema.interfaces import IVocabularyTokenized
+from plone.restapi.interfaces import IFieldSerializer
+from plone.restapi.serializer.dxfields import DefaultFieldSerializer
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+@adapter(ICollection, IDexterityContent, IExportImportRequestMarker)
+@implementer(IFieldSerializer)
+class CollectionFieldSerializer(DefaultFieldSerializer):
+    def __call__(self):
+        """Override default serializer:
+        1. Export only the value, not a token/title dict.
+        2. Do not drop values that are not in the vocabulary.
+           Instead log info so you can handle the data.
+        """
+        # Binding is necessary for named vocabularies
+        if IField.providedBy(self.field):
+            self.field = self.field.bind(self.context)
+        value = self.get_value()
+        value_type = self.field.value_type
+        if (
+            value is not None
+            and IChoice.providedBy(value_type)
+            and IVocabularyTokenized.providedBy(value_type.vocabulary)
+        ):
+            for v in value:
+                try:
+                    value_type.vocabulary.getTerm(v)
+                except LookupError:
+                    if v not in [self.field.default, self.field.missing_value]:
+                        logger.info(
+                            "Term lookup error: %r not in vocabulary %r for field %r of %r",
+                            v,
+                            value_type.vocabularyName,
+                            self.field.__name__,
+                            self.context,
+                        )
+        return json_compatible(value)
+
+
+@adapter(IChoice, IDexterityContent, IExportImportRequestMarker)
+@implementer(IFieldSerializer)
+class ChoiceFieldSerializer(DefaultFieldSerializer):
+    def __call__(self):
+        """Override default serializer:
+        1. Export only the value, not a token/title dict.
+        2. Do not drop values that are not in the vocabulary.
+           Instead log info so you can handle the data.
+        """
+        # Binding is necessary for named vocabularies
+        if IField.providedBy(self.field):
+            self.field = self.field.bind(self.context)
+        value = self.get_value()
+        if value is not None and IVocabularyTokenized.providedBy(self.field.vocabulary):
+            try:
+                self.field.vocabulary.getTerm(value)
+            except LookupError:
+                if value not in [self.field.default, self.field.missing_value]:
+                    logger.info(
+                        "Term lookup error: %r not in vocabulary %r for field %r of %r",
+                        value,
+                        self.field.vocabularyName,
+                        self.field.__name__,
+                        self.context,
+                    )
+        return json_compatible(value)