Improve retrieval of original name

Having used AIPscan a little more, leaving the name blank is strange
to look at, but we also cannot always retrieve the original name. We
do our best to a) retrieve the name in this commit, as well as b)
populate the name with the transfer UUID as an alternative.

AIPscan/Aggregator/mets_parse_helpers.py

@@ -44,36 +44,43 @@ def parse_mets_with_metsrw(mets_file):
 
 
 def get_aip_original_name(mets):
-    """Retrieve PREMIS original name from a METSDocument object."""
+    """Retrieve PREMIS original name from a METSDocument object.
+
+    If the original name cannot be reliably retrieved from the METS file
+    a METSError exception is returned to be handled by the caller as
+    desired.
+    """
 
     # Negated as we're going to want to remove this length of values.
     NAMESUFFIX = -len("-00000000-0000-0000-0000-000000000000")
 
+    # The transfer directory prefix is a directory prefix that can also
+    # exist in a dmdSec intellectual entity and we want to identify and
+    # ignore those.
+    TRANSFER_DIR_PREFIX = "%transferDirectory%"
+
     NAMESPACES = {u"premis": u"http://www.loc.gov/premis/v3"}
     ELEM_ORIGINAL_NAME_PATTERN = ".//premis:originalName"
 
-    FIRST_DMDSEC = "dmdSec_1"
-
     original_name = ""
     for fsentry in mets.all_files():
-        try:
-            dmdsec = fsentry.dmdsecs[0]
-            if dmdsec.id_string != FIRST_DMDSEC:
-                continue
+        for dmdsec in fsentry.dmdsecs:
             dmd_element = dmdsec.serialize()
             full_name = dmd_element.find(
                 ELEM_ORIGINAL_NAME_PATTERN, namespaces=NAMESPACES
             )
+            if full_name is not None and full_name.text.startswith(TRANSFER_DIR_PREFIX):
+                # We don't want this value, it will usually represent an
+                # directory entity.
+                continue
             try:
                 original_name = full_name.text[:NAMESUFFIX]
             except AttributeError:
-                pass
-            break
-        except IndexError:
-            pass
+                continue
 
+    # There should be a transfer name in every METS.
     if original_name == "":
-        raise METSError()
+        raise METSError("Cannot locate transfer name in METS")
 
     return original_name
 

AIPscan/Aggregator/tasks.py

@@ -294,7 +294,7 @@ def get_mets(
     except METSError:
         # Some other error with the METS file that we might want to
         # log and act upon.
-        originalName = ""
+        originalName = packageUUID
 
     aip = create_aip_object(
         package_uuid=packageUUID,