Do the MSS check last

It makes sense to check locally (to the data portal infrastructure) before we check the MSS.

iiif/profiles/mss.py

@@ -260,20 +260,15 @@ async def get_mss_doc(self, name: str, refresh: bool = False) -> Optional[dict]:
         """
 
         async def get_doc() -> Optional[dict]:
-            # first, check with mss that the irn is valid
-            async with self.mss_session.get(f'{self.mss_url}/{name}') as response:
-                if not response.ok:
-                    return None
-
-            # next, check that we have a document in the mss index
+            # first, check that we have a document in the mss index
             doc_url = f'{next(self.es_hosts)}/{self.mss_index}/_doc/{name}'
             async with self.es_session.get(doc_url) as response:
                 text = await response.text(encoding='utf-8')
                 info = orjson.loads(text)
                 if not info['found']:
                     return None
 
-            # finally, check that the irn is associated with a record in the collection datasets
+            # next, check that the irn is associated with a record in the collection datasets
             count_url = f'{next(self.es_hosts)}/{self.collection_indices}/_count'
             search = Search() \
                 .filter('term', **{'data.associatedMedia._id': name}) \
@@ -283,6 +278,11 @@ async def get_doc() -> Optional[dict]:
                 if orjson.loads(text)['count'] == 0:
                     return None
 
+            # finally, check with mss that the irn is valid
+            async with self.mss_session.get(f'{self.mss_url}/{name}') as response:
+                if not response.ok:
+                    return None
+
             # if we get here then all 3 checks have passed
             return info['_source']