significantly improve get_missing_events fed code

Signed-off-by: June Clementine Strawberry <june@3.dog>

src/api/server/backfill.rs

@@ -6,11 +6,17 @@ use conduwuit::{
 	utils::{IterStream, ReadyExt, stream::TryTools},
 };
 use futures::{FutureExt, StreamExt, TryStreamExt};
-use ruma::{MilliSecondsSinceUnixEpoch, api::federation::backfill::get_backfill, uint};
+use ruma::{MilliSecondsSinceUnixEpoch, api::federation::backfill::get_backfill};
 
 use super::AccessCheck;
 use crate::Ruma;
 
+/// arbitrary number but synapse's is 100 and we can handle lots of these
+/// anyways
+const LIMIT_MAX: usize = 150;
+/// no spec defined number but we can handle a lot of these
+const LIMIT_DEFAULT: usize = 50;
+
 /// # `GET /_matrix/federation/v1/backfill/<room_id>`
 ///
 /// Retrieves events from before the sender joined the room, if the room's
@@ -30,9 +36,9 @@ pub(crate) async fn get_backfill_route(
 
 	let limit = body
 		.limit
-		.min(uint!(100))
 		.try_into()
-		.expect("UInt could not be converted to usize");
+		.unwrap_or(LIMIT_DEFAULT)
+		.min(LIMIT_MAX);
 
 	let from = body
 		.v

src/api/server/get_missing_events.rs

@@ -1,13 +1,19 @@
 use axum::extract::State;
-use conduwuit::{Error, Result};
+use conduwuit::{
-use ruma::{
+	Result, debug, debug_info, debug_warn,
-	CanonicalJsonValue, EventId, RoomId,
+	utils::{self},
-	api::{client::error::ErrorKind, federation::event::get_missing_events},
+	warn,
 };
+use ruma::api::federation::event::get_missing_events;
 
 use super::AccessCheck;
 use crate::Ruma;
 
+/// arbitrary number but synapse's is 20 and we can handle lots of these anyways
+const LIMIT_MAX: usize = 50;
+/// spec says default is 10
+const LIMIT_DEFAULT: usize = 10;
+
 /// # `POST /_matrix/federation/v1/get_missing_events/{roomId}`
 ///
 /// Retrieves events that the sender is missing.
@@ -24,7 +30,11 @@ pub(crate) async fn get_missing_events_route(
 	.check()
 	.await?;
 
-	let limit = body.limit.try_into()?;
+	let limit = body
+		.limit
+		.try_into()
+		.unwrap_or(LIMIT_DEFAULT)
+		.min(LIMIT_MAX);
 
 	let mut queued_events = body.latest_events.clone();
 	// the vec will never have more entries the limit
@@ -32,60 +42,51 @@ pub(crate) async fn get_missing_events_route(
 
 	let mut i: usize = 0;
 	while i < queued_events.len() && events.len() < limit {
-		if let Ok(pdu) = services
+		let Ok(pdu) = services.rooms.timeline.get_pdu(&queued_events[i]).await else {
+			debug_info!(?body.origin, "Event {} does not exist locally, skipping", &queued_events[i]);
+			i = i.saturating_add(1);
+			continue;
+		};
+
+		if pdu.room_id != body.room_id {
+			warn!(?body.origin,
+				"Got an event for the wrong room in database. Found {:?} in {:?}, server requested events in {:?}. Skipping.",
+				pdu.event_id, pdu.room_id, body.room_id
+			);
+			i = i.saturating_add(1);
+			continue;
+		}
+
+		if body.earliest_events.contains(&queued_events[i]) {
+			i = i.saturating_add(1);
+			continue;
+		}
+
+		if !services
 			.rooms
-			.timeline
+			.state_accessor
-			.get_pdu_json(&queued_events[i])
+			.server_can_see_event(body.origin(), &body.room_id, &queued_events[i])
 			.await
 		{
-			let room_id_str = pdu
+			debug!(?body.origin, "Server cannot see {:?} in {:?}, skipping", pdu.event_id, pdu.room_id);
-				.get("room_id")
+			i = i.saturating_add(1);
-				.and_then(|val| val.as_str())
+			continue;
-				.ok_or_else(|| Error::bad_database("Invalid event in database."))?;
-
-			let event_room_id = <&RoomId>::try_from(room_id_str)
-				.map_err(|_| Error::bad_database("Invalid room_id in event in database."))?;
-
-			if event_room_id != body.room_id {
-				return Err(Error::BadRequest(ErrorKind::InvalidParam, "Event from wrong room."));
-			}
-
-			if body.earliest_events.contains(&queued_events[i]) {
-				i = i.saturating_add(1);
-				continue;
-			}
-
-			if !services
-				.rooms
-				.state_accessor
-				.server_can_see_event(body.origin(), &body.room_id, &queued_events[i])
-				.await
-			{
-				i = i.saturating_add(1);
-				continue;
-			}
-
-			let prev_events = pdu
-				.get("prev_events")
-				.and_then(CanonicalJsonValue::as_array)
-				.unwrap_or_default();
-
-			queued_events.extend(
-				prev_events
-					.iter()
-					.map(<&EventId>::try_from)
-					.filter_map(Result::ok)
-					.map(ToOwned::to_owned),
-			);
-
-			events.push(
-				services
-					.sending
-					.convert_to_outgoing_federation_event(pdu)
-					.await,
-			);
 		}
-		i = i.saturating_add(1);
+
+		let Ok(pdu_json) = utils::to_canonical_object(&pdu) else {
+			debug_warn!(?body.origin, "Failed to convert PDU in database to canonical JSON: {pdu:?}");
+			i = i.saturating_add(1);
+			continue;
+		};
+
+		queued_events.extend(pdu.prev_events.iter().map(ToOwned::to_owned));
+
+		events.push(
+			services
+				.sending
+				.convert_to_outgoing_federation_event(pdu_json)
+				.await,
+		);
 	}
 
 	Ok(get_missing_events::v1::Response { events })