1 files changed, 53 insertions, 11 deletions
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py
index 9d5310851c..1535cc5339 100644
--- a/synapse/events/third_party_rules.py
+++ b/synapse/events/third_party_rules.py
@@ -12,10 +12,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from typing import Callable
 
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
-from synapse.types import Requester
+from synapse.types import Requester, StateMap
 
 
 class ThirdPartyEventRules:
@@ -38,7 +39,7 @@ class ThirdPartyEventRules:
 
         if module is not None:
             self.third_party_rules = module(
-                config=config, http_client=hs.get_simple_http_client()
+                config=config, module_api=hs.get_module_api(),
             )
 
     async def check_event_allowed(
@@ -59,12 +60,14 @@ class ThirdPartyEventRules:
         prev_state_ids = await context.get_prev_state_ids()
 
         # Retrieve the state events from the database.
-        state_events = {}
-        for key, event_id in prev_state_ids.items():
-            state_events[key] = await self.store.get_event(event_id, allow_none=True)
+        events = await self.store.get_events(prev_state_ids.values())
+        state_events = {(ev.type, ev.state_key): ev for ev in events.values()}
 
-        ret = await self.third_party_rules.check_event_allowed(event, state_events)
-        return ret
+        # The module can modify the event slightly if it wants, but caution should be
+        # exercised, and it's likely to go very wrong if applied to events received over
+        # federation.
+
+        return await self.third_party_rules.check_event_allowed(event, state_events)
 
     async def on_create_room(
         self, requester: Requester, config: dict, is_requester_admin: bool
@@ -106,6 +109,48 @@ class ThirdPartyEventRules:
         if self.third_party_rules is None:
             return True
 
+        state_events = await self._get_state_map_for_room(room_id)
+
+        ret = await self.third_party_rules.check_threepid_can_be_invited(
+            medium, address, state_events
+        )
+        return ret
+
+    async def check_visibility_can_be_modified(
+        self, room_id: str, new_visibility: str
+    ) -> bool:
+        """Check if a room is allowed to be published to, or removed from, the public room
+        list.
+
+        Args:
+            room_id: The ID of the room.
+            new_visibility: The new visibility state. Either "public" or "private".
+
+        Returns:
+            True if the room's visibility can be modified, False if not.
+        """
+        if self.third_party_rules is None:
+            return True
+
+        check_func = getattr(
+            self.third_party_rules, "check_visibility_can_be_modified", None
+        )
+        if not check_func or not isinstance(check_func, Callable):
+            return True
+
+        state_events = await self._get_state_map_for_room(room_id)
+
+        return await check_func(room_id, state_events, new_visibility)
+
+    async def _get_state_map_for_room(self, room_id: str) -> StateMap[EventBase]:
+        """Given a room ID, return the state events of that room.
+
+        Args:
+            room_id: The ID of the room.
+
+        Returns:
+            A dict mapping (event type, state key) to state event.
+        """
         state_ids = await self.store.get_filtered_current_state_ids(room_id)
         room_state_events = await self.store.get_events(state_ids.values())
 
@@ -113,7 +158,4 @@ class ThirdPartyEventRules:
         for key, event_id in state_ids.items():
             state_events[key] = room_state_events[event_id]
 
-        ret = await self.third_party_rules.check_threepid_can_be_invited(
-            medium, address, state_events
-        )
-        return ret
+        return state_events