Support v1/v2 prev_events/auth_events outgoing federation format. (#12)

Support v1/v2 prev_events/auth_events when handling outlier pdu. (#12)

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/matrix/pdu/format.rs

@@ -1,6 +1,12 @@
-use ruma::{CanonicalJsonObject, CanonicalJsonValue, RoomVersionId};
+use ruma::{
+	CanonicalJsonObject, CanonicalJsonValue, EventId, RoomVersionId,
+	room_version_rules::{EventsReferenceFormatVersion, RoomVersionRules},
+};
 
-use crate::{is_equal_to, matrix::room_version};
+use crate::{
+	Result, err, extract_variant, is_equal_to,
+	matrix::{PduEvent, room_version},
+};
 
 pub fn into_outgoing_federation(
 	mut pdu_json: CanonicalJsonObject,
@@ -35,5 +41,67 @@ pub fn into_outgoing_federation(
 		}
 	}
 
+	if matches!(room_rules.events_reference_format, EventsReferenceFormatVersion::V1) {
+		if let Some(value) = pdu_json.get_mut("auth_events") {
+			mutate_outgoing_reference_format(value);
+		}
+		if let Some(value) = pdu_json.get_mut("prev_events") {
+			mutate_outgoing_reference_format(value);
+		}
+	}
+
 	pdu_json
 }
+
+fn mutate_outgoing_reference_format(value: &mut CanonicalJsonValue) {
+	value
+		.as_array_mut()
+		.into_iter()
+		.flatten()
+		.for_each(|value| {
+			if let Some(event_id) = value.as_str().map(ToOwned::to_owned) {
+				*value = CanonicalJsonValue::Array(vec![
+					CanonicalJsonValue::String(event_id),
+					CanonicalJsonValue::Object([(String::new(), "".into())].into()),
+				]);
+			}
+		});
+}
+
+pub fn from_incoming_federation(
+	event_id: &EventId,
+	pdu_json: &mut CanonicalJsonObject,
+	room_rules: &RoomVersionRules,
+) -> Result<PduEvent> {
+	if matches!(room_rules.events_reference_format, EventsReferenceFormatVersion::V1) {
+		if let Some(value) = pdu_json.get_mut("auth_events") {
+			mutate_incoming_reference_format(value);
+		}
+		if let Some(value) = pdu_json.get_mut("prev_events") {
+			mutate_incoming_reference_format(value);
+		}
+	}
+
+	pdu_json.insert("event_id".to_owned(), CanonicalJsonValue::String(event_id.into()));
+
+	serde_json::from_value::<PduEvent>(serde_json::to_value(&pdu_json)?)
+		.map_err(|e| err!(Request(BadJson(debug_warn!("Event is not a valid PDU: {e}")))))
+}
+
+fn mutate_incoming_reference_format(value: &mut CanonicalJsonValue) {
+	value
+		.as_array_mut()
+		.into_iter()
+		.flat_map(|vec| vec.iter_mut())
+		.for_each(|value| {
+			let event_id = value
+				.as_array()
+				.into_iter()
+				.find_map(|vec| vec.first())
+				.and_then(|val| extract_variant!(val, CanonicalJsonValue::String))
+				.cloned()
+				.unwrap_or_default();
+
+			*value = CanonicalJsonValue::String(event_id);
+		});
+}

src/service/rooms/event_handler/handle_outlier_pdu.rs

@@ -1,11 +1,11 @@
 use futures::{StreamExt, TryFutureExt};
 use ruma::{
-	CanonicalJsonObject, CanonicalJsonValue, EventId, RoomId, RoomVersionId, ServerName,
-	events::TimelineEventType,
+	CanonicalJsonObject, EventId, RoomId, RoomVersionId, ServerName, events::TimelineEventType,
 };
 use tuwunel_core::{
 	Err, Result, debug, debug_info, err, implement,
 	matrix::{Event, PduEvent, event::TypeExt, room_version},
+	pdu::format::from_incoming_federation,
 	ref_at, state_res, trace,
 	utils::{future::TryExtExt, stream::IterStream},
 	warn,
@@ -66,12 +66,11 @@ pub(super) async fn handle_outlier_pdu(
 		},
 	};
 
-	// Now that we have checked the signature and hashes we can add the eventID and
-	// convert to our PduEvent type
-	pdu_json.insert("event_id".to_owned(), CanonicalJsonValue::String(event_id.to_string()));
+	let room_rules = room_version::rules(room_version)?;
 
-	let event = serde_json::from_value::<PduEvent>(serde_json::to_value(&pdu_json)?)
-		.map_err(|e| err!(Request(BadJson(debug_warn!("Event is not a valid PDU: {e}")))))?;
+	// Now that we have checked the signature and hashes we can make mutations and
+	// convert to our PduEvent type.
+	let event = from_incoming_federation(event_id, &mut pdu_json, &room_rules)?;
 
 	check_room_id(room_id, &event)?;
 
@@ -89,7 +88,6 @@ pub(super) async fn handle_outlier_pdu(
 	//    auth events
 	debug!("Checking based on auth events");
 
-	let room_rules = room_version::rules(room_version)?;
 	let is_hydra = !room_rules
 		.event_format
 		.allow_room_create_in_auth_events;