Add a timeout callback for detecting when a View times out

discord/ui/view.py

@@ -47,6 +47,7 @@ __all__ = (
 if TYPE_CHECKING:
     from ..interactions import Interaction
     from ..types.components import Component as ComponentPayload
+    from ..state import ConnectionState
 
 
 def _walk_all_components(components: List[Component]) -> Iterator[Component]:
@@ -118,6 +119,7 @@ class View:
 
         self.id = os.urandom(16).hex()
         self._cancel_callback: Optional[Callable[[View], None]] = None
+        self._timeout_handler: Optional[asyncio.TimerHandle] = None
         self._stopped = asyncio.Event()
 
     def to_components(self) -> List[Dict[str, Any]]:
@@ -225,6 +227,13 @@ class View:
         """
         return True
 
+    async def on_timeout(self) -> None:
+        """|coro|
+
+        A callback that is called when a view's timeout elapses without being explicitly stopped.
+        """
+        pass
+
     async def _scheduled_task(self, state: Any, item: Item, interaction: Interaction):
         try:
             allow = await self.interaction_check(interaction)
@@ -238,6 +247,15 @@ class View:
         if not interaction.response._responded:
             await interaction.response.defer()
 
+    def _start_listening(self, store: ViewStore) -> None:
+        self._cancel_callback = partial(store.remove_view)
+        if self.timeout:
+            loop = asyncio.get_running_loop()
+            self._timeout_handler = loop.call_later(self.timeout, self.dispatch_timeout)
+
+    def dispatch_timeout(self):
+        asyncio.create_task(self.on_timeout(), name=f'discord-ui-view-timeout-{self.id}')
+
     def dispatch(self, state: Any, item: Item, interaction: Interaction):
         asyncio.create_task(self._scheduled_task(state, item, interaction), name=f'discord-ui-view-dispatch-{self.id}')
 
@@ -268,6 +286,9 @@ class View:
         This operation cannot be undone.
         """
         self._stopped.set()
+        if self._timeout_handler:
+            self._timeout_handler.cancel()
+
         if self._cancel_callback:
             self._cancel_callback(self)
 
@@ -280,12 +301,12 @@ class View:
 
 
 class ViewStore:
-    def __init__(self, state):
+    def __init__(self, state: ConnectionState):
         # (component_type, custom_id): (View, Item, Expiry)
         self._views: Dict[Tuple[int, str], Tuple[View, Item, Optional[float]]] = {}
         # message_id: View
         self._synced_message_views: Dict[int, View] = {}
-        self._state = state
+        self._state: ConnectionState = state
 
     def __verify_integrity(self):
         to_remove: List[Tuple[int, str]] = []
@@ -301,7 +322,7 @@ class ViewStore:
         self.__verify_integrity()
 
         expiry = view._expires_at
-        view._cancel_callback = partial(self.remove_view)
+        view._start_listening(self)
         for item in view.children:
             if item.is_dispatchable():
                 self._views[(item.type.value, item.custom_id)] = (view, item, expiry)  # type: ignore