Invites v2 endpoint (#952)

* Start converting v1 invite endpoint to v2

* Update gomatrixserverlib

* Early federationsender code for sending invites

* Sending invites sorta happens now

* Populate invite request with stripped state

* Remodel a bit, don't reflect received invites

* Handle invite_room_state

* Handle room versions a bit better

* Update gomatrixserverlib

* Tweak order in destinationQueue.next

* Revert check in processMessage

* Tweak federation sender destination queue code a bit

* Add comments

1 files changed, 102 insertions, 18 deletions

diff --git a/federationsender/consumers/roomserver.go b/federationsender/consumers/roomserver.go
index 8ab2affe..f59405af 100644
--- a/federationsender/consumers/roomserver.go
+++ b/federationsender/consumers/roomserver.go
@@ -32,6 +32,7 @@ import (
 
 // OutputRoomEventConsumer consumes events that originated in the room server.
 type OutputRoomEventConsumer struct {
+	cfg                *config.Dendrite
 	roomServerConsumer *common.ContinualConsumer
 	db                 storage.Database
 	queues             *queue.OutgoingQueues
@@ -52,6 +53,7 @@ func NewOutputRoomEventConsumer(
 		PartitionStore: store,
 	}
 	s := &OutputRoomEventConsumer{
+		cfg:                cfg,
 		roomServerConsumer: &consumer,
 		db:                 store,
 		queues:             queues,
@@ -79,29 +81,48 @@ func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
 		log.WithError(err).Errorf("roomserver output log: message parse failure")
 		return nil
 	}
-	if output.Type != api.OutputTypeNewRoomEvent {
+
+	switch output.Type {
+	case api.OutputTypeNewRoomEvent:
+		ev := &output.NewRoomEvent.Event
+		log.WithFields(log.Fields{
+			"event_id":       ev.EventID(),
+			"room_id":        ev.RoomID(),
+			"send_as_server": output.NewRoomEvent.SendAsServer,
+		}).Info("received room event from roomserver")
+
+		if err := s.processMessage(*output.NewRoomEvent); err != nil {
+			// panic rather than continue with an inconsistent database
+			log.WithFields(log.Fields{
+				"event":      string(ev.JSON()),
+				"add":        output.NewRoomEvent.AddsStateEventIDs,
+				"del":        output.NewRoomEvent.RemovesStateEventIDs,
+				log.ErrorKey: err,
+			}).Panicf("roomserver output log: write room event failure")
+			return nil
+		}
+	case api.OutputTypeNewInviteEvent:
+		ev := &output.NewInviteEvent.Event
+		log.WithFields(log.Fields{
+			"event_id":  ev.EventID(),
+			"room_id":   ev.RoomID(),
+			"state_key": ev.StateKey(),
+		}).Info("received invite event from roomserver")
+
+		if err := s.processInvite(*output.NewInviteEvent); err != nil {
+			// panic rather than continue with an inconsistent database
+			log.WithFields(log.Fields{
+				"event":      string(ev.JSON()),
+				log.ErrorKey: err,
+			}).Panicf("roomserver output log: write invite event failure")
+			return nil
+		}
+	default:
 		log.WithField("type", output.Type).Debug(
 			"roomserver output log: ignoring unknown output type",
 		)
 		return nil
 	}
-	ev := &output.NewRoomEvent.Event
-	log.WithFields(log.Fields{
-		"event_id":       ev.EventID(),
-		"room_id":        ev.RoomID(),
-		"send_as_server": output.NewRoomEvent.SendAsServer,
-	}).Info("received event from roomserver")
-
-	if err := s.processMessage(*output.NewRoomEvent); err != nil {
-		// panic rather than continue with an inconsistent database
-		log.WithFields(log.Fields{
-			"event":      string(ev.JSON()),
-			log.ErrorKey: err,
-			"add":        output.NewRoomEvent.AddsStateEventIDs,
-			"del":        output.NewRoomEvent.RemovesStateEventIDs,
-		}).Panicf("roomserver output log: write event failure")
-		return nil
-	}
 
 	return nil
 }
@@ -159,6 +180,69 @@ func (s *OutputRoomEventConsumer) processMessage(ore api.OutputNewRoomEvent) err
 	)
 }
 
+// processInvite handles an invite event for sending over federation.
+func (s *OutputRoomEventConsumer) processInvite(oie api.OutputNewInviteEvent) error {
+	// Don't try to reflect and resend invites that didn't originate from us.
+	if s.cfg.Matrix.ServerName != oie.Event.Origin() {
+		return nil
+	}
+
+	// When sending a v2 invite, the inviting server should try and include
+	// a "stripped down" version of the room state. This is pretty much just
+	// enough information for the remote side to show something useful to the
+	// user, like the room name, aliases etc.
+	strippedState := []gomatrixserverlib.InviteV2StrippedState{}
+	stateWanted := []string{
+		gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias,
+		gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules,
+	}
+
+	// For each of the state keys that we want to try and send, ask the
+	// roomserver if we have a state event for that room that matches the
+	// state key.
+	for _, wanted := range stateWanted {
+		queryReq := api.QueryLatestEventsAndStateRequest{
+			RoomID: oie.Event.RoomID(),
+			StateToFetch: []gomatrixserverlib.StateKeyTuple{
+				gomatrixserverlib.StateKeyTuple{
+					EventType: wanted,
+					StateKey:  "",
+				},
+			},
+		}
+		// If this fails then we just move onto the next event - we don't
+		// actually know at this point whether the room even has that type
+		// of state.
+		queryRes := api.QueryLatestEventsAndStateResponse{}
+		if err := s.query.QueryLatestEventsAndState(context.TODO(), &queryReq, &queryRes); err != nil {
+			log.WithFields(log.Fields{
+				"room_id":    queryReq.RoomID,
+				"event_type": wanted,
+			}).WithError(err).Info("couldn't find state to strip")
+			continue
+		}
+		// Append the stripped down copy of the state to our list.
+		for _, headeredEvent := range queryRes.StateEvents {
+			event := headeredEvent.Unwrap()
+			strippedState = append(strippedState, gomatrixserverlib.NewInviteV2StrippedState(&event))
+
+			log.WithFields(log.Fields{
+				"room_id":    queryReq.RoomID,
+				"event_type": event.Type(),
+			}).Info("adding stripped state")
+		}
+	}
+
+	// Build the invite request with the info we've got.
+	inviteReq, err := gomatrixserverlib.NewInviteV2Request(&oie.Event, strippedState)
+	if err != nil {
+		return fmt.Errorf("gomatrixserverlib.NewInviteV2Request: %w", err)
+	}
+
+	// Send the event.
+	return s.queues.SendInvite(&inviteReq)
+}
+
 // joinedHostsAtEvent works out a list of matrix servers that were joined to
 // the room at the event.
 // It is important to use the state at the event for sending messages because: