adapter: Allow optional contentType in Blob and File

Currently, the JSON and XMOL deserializiers raise an error when parsing Blob or File submodels that do not include a contentType

The contentType attribute has a cardinality of 0..1 for both classes and should therefore be optional.
The implementation now aligns with this specification and defaults to None if the field is absent in the data.

Author: paul-gerber-svg

sdk/basyx/aas/adapter/json/json_deserialization.py

@@ -692,18 +692,20 @@ def _construct_submodel_element_list(cls, dct: Dict[str, object], object_class=m
 
     @classmethod
     def _construct_blob(cls, dct: Dict[str, object], object_class=model.Blob) -> model.Blob:
+        content_type = _get_ts(dct, "contentType", str) if 'contentType' in dct else None
         ret = object_class(id_short=None,
-                           content_type=_get_ts(dct, "contentType", str))
+                           content_type=content_type)
         cls._amend_abstract_attributes(ret, dct)
         if 'value' in dct:
             ret.value = base64.b64decode(_get_ts(dct, 'value', str))
         return ret
 
     @classmethod
     def _construct_file(cls, dct: Dict[str, object], object_class=model.File) -> model.File:
+        content_type = _get_ts(dct, "contentType", str) if 'contentType' in dct else None
         ret = object_class(id_short=None,
                            value=None,
-                           content_type=_get_ts(dct, "contentType", str))
+                           content_type=content_type)
         cls._amend_abstract_attributes(ret, dct)
         if 'value' in dct and dct['value'] is not None:
             ret.value = _get_ts(dct, 'value', str)

sdk/basyx/aas/adapter/xml/xml_deserialization.py

@@ -804,7 +804,7 @@ def construct_basic_event_element(cls, element: etree._Element, object_class=mod
     def construct_blob(cls, element: etree._Element, object_class=model.Blob, **_kwargs: Any) -> model.Blob:
         blob = object_class(
             None,
-            _child_text_mandatory(element, NS_AAS + "contentType")
+            _get_text_or_none(element.find(NS_AAS + "contentType"))
         )
         value = _get_text_or_none(element.find(NS_AAS + "value"))
         if value is not None:
@@ -851,7 +851,7 @@ def construct_entity(cls, element: etree._Element, object_class=model.Entity, **
     def construct_file(cls, element: etree._Element, object_class=model.File, **_kwargs: Any) -> model.File:
         file = object_class(
             None,
-            _child_text_mandatory(element, NS_AAS + "contentType")
+            _get_text_or_none(element.find(NS_AAS + "contentType"))
         )
         value = _get_text_or_none(element.find(NS_AAS + "value"))
         if value is not None: