Add admin handler to list of handlers used for background tasks (#17847)

Fixes #17823

While we're at it, makes a change where the redactions are sent as the
admin if the user is not a member of the server (otherwise these fail
with a "User must be our own" message).

1 files changed, 5 insertions, 1 deletions

diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py

index 851fe57a17..d1989e9d2c 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -73,6 +73,8 @@ class AdminHandler:
             self._redact_all_events, REDACT_ALL_EVENTS_ACTION_NAME
         )
 
+        self.hs = hs
+
     async def get_redact_task(self, redact_id: str) -> Optional[ScheduledTask]:
         """Get the current status of an active redaction process
 
@@ -423,8 +425,10 @@ class AdminHandler:
         user_id = task.params.get("user_id")
         assert user_id is not None
 
+        # puppet the user if they're ours, otherwise use admin to redact
         requester = create_requester(
-            user_id, authenticated_entity=admin.user.to_string()
+            user_id if self.hs.is_mine_id(user_id) else admin.user.to_string(),
+            authenticated_entity=admin.user.to_string(),
         )
 
         reason = task.params.get("reason")