Allow modules to delete rooms. (#15997)

* Allow user_id to be optional for room deletion

* Add module API method to delete a room

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

* Don't worry about the case block=True && requester_user_id is None

---------

Signed-off-by: Olivier Wilkinson (reivilibre) <oliverw@matrix.org>

5 files changed, 41 insertions, 6 deletions

diff --git a/changelog.d/15997.misc b/changelog.d/15997.misc
new file mode 100644
index 0000000000..94768c3cb8
--- /dev/null
+++ b/changelog.d/15997.misc
@@ -0,0 +1 @@
+Allow modules to delete rooms.
\ No newline at end of file
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index e5ac9096cc..19cf5a2b43 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -713,7 +713,7 @@ class PaginationHandler:
         self,
         delete_id: str,
         room_id: str,
-        requester_user_id: str,
+        requester_user_id: Optional[str],
         new_room_user_id: Optional[str] = None,
         new_room_name: Optional[str] = None,
         message: Optional[str] = None,
@@ -732,6 +732,10 @@ class PaginationHandler:
             requester_user_id:
                 User who requested the action. Will be recorded as putting the room on the
                 blocking list.
+                If None, the action was not manually requested but instead
+                triggered automatically, e.g. through a Synapse module
+                or some other policy.
+                MUST NOT be None if block=True.
             new_room_user_id:
                 If set, a new room will be created with this user ID
                 as the creator and admin, and all users in the old room will be
@@ -818,7 +822,7 @@ class PaginationHandler:
     def start_shutdown_and_purge_room(
         self,
         room_id: str,
-        requester_user_id: str,
+        requester_user_id: Optional[str],
         new_room_user_id: Optional[str] = None,
         new_room_name: Optional[str] = None,
         message: Optional[str] = None,
@@ -833,6 +837,10 @@ class PaginationHandler:
             requester_user_id:
                 User who requested the action and put the room on the
                 blocking list.
+                If None, the action was not manually requested but instead
+                triggered automatically, e.g. through a Synapse module
+                or some other policy.
+                MUST NOT be None if block=True.
             new_room_user_id:
                 If set, a new room will be created with this user ID
                 as the creator and admin, and all users in the old room will be
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 0513e28aab..7a762c8511 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -1787,7 +1787,7 @@ class RoomShutdownHandler:
     async def shutdown_room(
         self,
         room_id: str,
-        requester_user_id: str,
+        requester_user_id: Optional[str],
         new_room_user_id: Optional[str] = None,
         new_room_name: Optional[str] = None,
         message: Optional[str] = None,
@@ -1811,6 +1811,10 @@ class RoomShutdownHandler:
             requester_user_id:
                 User who requested the action and put the room on the
                 blocking list.
+                If None, the action was not manually requested but instead
+                triggered automatically, e.g. through a Synapse module
+                or some other policy.
+                MUST NOT be None if block=True.
             new_room_user_id:
                 If set, a new room will be created with this user ID
                 as the creator and admin, and all users in the old room will be
@@ -1863,6 +1867,10 @@ class RoomShutdownHandler:
 
         # Action the block first (even if the room doesn't exist yet)
         if block:
+            if requester_user_id is None:
+                raise ValueError(
+                    "shutdown_room: block=True not allowed when requester_user_id is None."
+                )
             # This will work even if the room is already blocked, but that is
             # desirable in case the first attempt at blocking the room failed below.
             await self.store.block_room(room_id, requester_user_id)
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 2f00a7ba20..d6efe10a28 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -1730,6 +1730,19 @@ class ModuleApi:
         room_alias_str = room_alias.to_string() if room_alias else None
         return room_id, room_alias_str
 
+    async def delete_room(self, room_id: str) -> None:
+        """
+        Schedules the deletion of a room from Synapse's database.
+
+        If the room is already being deleted, this method does nothing.
+        This method does not wait for the room to be deleted.
+
+        Added in Synapse v1.89.0.
+        """
+        # Future extensions to this method might want to e.g. allow use of `force_purge`.
+        # TODO In the future we should make sure this is persistent.
+        self._hs.get_pagination_handler().start_shutdown_and_purge_room(room_id, None)
+
     async def set_displayname(
         self,
         user_id: UserID,
diff --git a/synapse/module_api/callbacks/third_party_event_rules_callbacks.py b/synapse/module_api/callbacks/third_party_event_rules_callbacks.py
index 911f37ba42..ecaeef3511 100644
--- a/synapse/module_api/callbacks/third_party_event_rules_callbacks.py
+++ b/synapse/module_api/callbacks/third_party_event_rules_callbacks.py
@@ -40,7 +40,7 @@ CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK = Callable[
     [str, StateMap[EventBase], str], Awaitable[bool]
 ]
 ON_NEW_EVENT_CALLBACK = Callable[[EventBase, StateMap[EventBase]], Awaitable]
-CHECK_CAN_SHUTDOWN_ROOM_CALLBACK = Callable[[str, str], Awaitable[bool]]
+CHECK_CAN_SHUTDOWN_ROOM_CALLBACK = Callable[[Optional[str], str], Awaitable[bool]]
 CHECK_CAN_DEACTIVATE_USER_CALLBACK = Callable[[str, bool], Awaitable[bool]]
 ON_PROFILE_UPDATE_CALLBACK = Callable[[str, ProfileInfo, bool, bool], Awaitable]
 ON_USER_DEACTIVATION_STATUS_CHANGED_CALLBACK = Callable[[str, bool, bool], Awaitable]
@@ -429,12 +429,17 @@ class ThirdPartyEventRulesModuleApiCallbacks:
                     "Failed to run module API callback %s: %s", callback, e
                 )
 
-    async def check_can_shutdown_room(self, user_id: str, room_id: str) -> bool:
+    async def check_can_shutdown_room(
+        self, user_id: Optional[str], room_id: str
+    ) -> bool:
         """Intercept requests to shutdown a room. If `False` is returned, the
          room must not be shut down.
 
         Args:
-            requester: The ID of the user requesting the shutdown.
+            user_id: The ID of the user requesting the shutdown.
+                If no user ID is supplied, then the room is being shut down through
+                some mechanism other than a user's request, e.g. through a module's
+                request.
             room_id: The ID of the room.
         """
         for callback in self._check_can_shutdown_room_callbacks: