Add helper to parse an enum from query args & use it. (#14956)

The `parse_enum` helper pulls an enum value from the query string
(by delegating down to the parse_string helper with values generated
from the enum).

This is used to pull out "f" and "b" in most places and then we thread
the resulting Direction enum throughout more code.

1 files changed, 3 insertions, 3 deletions

diff --git a/synapse/storage/databases/main/stats.py b/synapse/storage/databases/main/stats.py
index 0c1cbd540d..d7b7d0c3c9 100644
--- a/synapse/storage/databases/main/stats.py
+++ b/synapse/storage/databases/main/stats.py
@@ -22,7 +22,7 @@ from typing_extensions import Counter
 
 from twisted.internet.defer import DeferredLock
 
-from synapse.api.constants import EventContentFields, EventTypes, Membership
+from synapse.api.constants import Direction, EventContentFields, EventTypes, Membership
 from synapse.api.errors import StoreError
 from synapse.storage.database import (
     DatabasePool,
@@ -663,7 +663,7 @@ class StatsStore(StateDeltasStore):
         from_ts: Optional[int] = None,
         until_ts: Optional[int] = None,
         order_by: Optional[str] = UserSortOrder.USER_ID.value,
-        direction: Optional[str] = "f",
+        direction: Direction = Direction.FORWARDS,
         search_term: Optional[str] = None,
     ) -> Tuple[List[JsonDict], int]:
         """Function to retrieve a paginated list of users and their uploaded local media
@@ -714,7 +714,7 @@ class StatsStore(StateDeltasStore):
                     500, "Incorrect value for order_by provided: %s" % order_by
                 )
 
-            if direction == "b":
+            if direction == Direction.BACKWARDS:
                 order = "DESC"
             else:
                 order = "ASC"