Add back the users cache

Signed-off-by: Allie Crevier <[email protected]>

securedrop_client/storage.py

@@ -25,7 +25,7 @@
 import shutil
 from datetime import datetime
 from pathlib import Path
-from typing import Any, List, Tuple, Type, Union
+from typing import Any, Dict, List, Tuple, Type, Union
 
 from dateutil.parser import parse
 from sdclientapi import API
@@ -413,21 +413,30 @@ def update_replies(
     """
     local_replies_by_uuid = {r.uuid: r for r in local_replies}
     deleted_user = session.query(User).filter_by(username="deleted").one_or_none()
+    user_cache: Dict[str, User] = {}
     source_cache = SourceCache(session)
     for reply in remote_replies:
-        # If the account for the sender does not exist, then replies will need to be re-associated
-        # to a local "deleted" user account. The only reason this might happen is if the pre-2.2.0
-        # server returns a `journalist_uuid` that does not correspond to a uuid for a real user
-        # account.
-        user = session.query(User).filter_by(uuid=reply.journalist_uuid).one_or_none()
+        user = user_cache.get(reply.journalist_uuid)
         if not user:
-            logger.debug(f"Sender account with uuid='{reply.journalist_uuid}' does not exist")
-            if not deleted_user:
-                deleted_user = DeletedUser()
-                session.add(deleted_user)
-                session.commit()
-            user = deleted_user
-            logger.debug(f"Setting `journalist_id` for Reply '{reply.uuid}' to '{user.id}'")
+            user = session.query(User).filter_by(uuid=reply.journalist_uuid).one_or_none()
+
+            # If the account for the sender does not exist, then replies will need to be associated
+            # to a local "deleted" user account.
+            #
+            # Once support for the pre-2.2.0 server is deprecated, this code can be removed, and the
+            # client can rely entirely on the /users endpoint to manage user accounts. Until then,
+            # we must handle the case where the pre-2.2.0 server returns a `journalist_uuid` of
+            # "deleted" for a reply's sender when no actual account exists with that uuid.
+            if not user:
+                user = deleted_user
+                if not user:
+                    user = DeletedUser()
+                    session.add(user)
+                    session.commit()
+                    deleted_user = user
+
+            # Add the retrieved or newly created "deleted" user to the cache
+            user_cache[reply.journalist_uuid] = user
 
         local_reply = local_replies_by_uuid.get(reply.uuid)
         if local_reply: