Add relationship_room_id|servers to the unsigned section of events

federationsender/api/api.go

@@ -48,6 +48,7 @@ type FederationSenderInternalAPI interface {
 	// Query the server names of the joined hosts in a room.
 	// Unlike QueryJoinedHostsInRoom, this function returns a de-duplicated slice
 	// containing only the server names (without information for membership events).
+	// The response will include this server if they are joined to the room.
 	QueryJoinedHostServerNamesInRoom(
 		ctx context.Context,
 		request *QueryJoinedHostServerNamesInRoomRequest,

federationsender/internal/query.go

@@ -4,7 +4,6 @@ import (
 	"context"
 
 	"github.com/matrix-org/dendrite/federationsender/api"
-	"github.com/matrix-org/gomatrixserverlib"
 )
 
 // QueryJoinedHostServerNamesInRoom implements api.FederationSenderInternalAPI
@@ -13,17 +12,11 @@ func (f *FederationSenderInternalAPI) QueryJoinedHostServerNamesInRoom(
 	request *api.QueryJoinedHostServerNamesInRoomRequest,
 	response *api.QueryJoinedHostServerNamesInRoomResponse,
 ) (err error) {
-	joinedHosts, err := f.db.GetJoinedHosts(ctx, request.RoomID)
+	joinedHosts, err := f.db.GetJoinedHostsForRooms(ctx, []string{request.RoomID})
 	if err != nil {
 		return
 	}
-
-	response.ServerNames = make([]gomatrixserverlib.ServerName, 0, len(joinedHosts))
-	for _, host := range joinedHosts {
-		response.ServerNames = append(response.ServerNames, host.ServerName)
-	}
-
-	// TODO: remove duplicates?
+	response.ServerNames = joinedHosts
 
 	return
 }

internal/hooks/hooks.go

@@ -24,6 +24,15 @@ const (
 	// Usage:
 	//   hooks.Attach(hooks.KindNewEvent, func(headeredEvent interface{}) { ... })
 	KindNewEvent = "new_event"
+	// KindModifyNewEvent is a hook which is called with *gomatrixserverlib.HeaderedEvent
+	// It is run before a new event is processed by the roomserver. This hook can be used
+	// to modify the event before it is persisted by adding data to `unsigned`.
+	// Usage:
+	//   hooks.Attach(hooks.KindModifyNewEvent, func(headeredEvent interface{}) {
+	//     ev := headeredEvent.(*gomatrixserverlib.HeaderedEvent)
+	//     _ = ev.SetUnsignedField("key", "val")
+	//   })
+	KindModifyNewEvent = "modify_new_event"
 )
 
 var (

internal/mscs/msc2836/msc2836.go

@@ -22,6 +22,7 @@ import (
 	"net/http"
 
 	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	fs "github.com/matrix-org/dendrite/federationsender/api"
 	"github.com/matrix-org/dendrite/internal/hooks"
 	"github.com/matrix-org/dendrite/internal/httputil"
 	"github.com/matrix-org/dendrite/internal/setup"
@@ -31,7 +32,11 @@ import (
 	"github.com/matrix-org/util"
 )
 
-const constRelType = "m.reference"
+const (
+	constRelType     = "m.reference"
+	constRoomIDKey   = "relationship_room_id"
+	constRoomServers = "relationship_servers"
+)
 
 type EventRelationshipRequest struct {
 	EventID         string `json:"event_id"`
@@ -83,7 +88,7 @@ type EventRelationshipResponse struct {
 }
 
 // Enable this MSC
-func Enable(base *setup.BaseDendrite, rsAPI roomserver.RoomserverInternalAPI, userAPI userapi.UserInternalAPI) error {
+func Enable(base *setup.BaseDendrite, rsAPI roomserver.RoomserverInternalAPI, fsAPI fs.FederationSenderInternalAPI, userAPI userapi.UserInternalAPI) error {
 	db, err := NewDatabase(&base.Cfg.MSCs.Database)
 	if err != nil {
 		return fmt.Errorf("Cannot enable MSC2836: %w", err)
@@ -98,6 +103,55 @@ func Enable(base *setup.BaseDendrite, rsAPI roomserver.RoomserverInternalAPI, us
 			)
 		}
 	})
+	hooks.Attach(hooks.KindModifyNewEvent, func(headeredEvent interface{}) {
+		he := headeredEvent.(*gomatrixserverlib.HeaderedEvent)
+		ctx := context.Background()
+		// we only inject metadata for events our server sends
+		userID := he.Sender()
+		_, domain, err := gomatrixserverlib.SplitID('@', userID)
+		if err != nil {
+			return
+		}
+		if domain != base.Cfg.Global.ServerName {
+			return
+		}
+		// if this event has an m.relationship, add on the room_id and servers to unsigned
+		parent, child, relType := parentChildEventIDs(he)
+		if parent == "" || child == "" || relType == "" {
+			return
+		}
+		event, joinedToRoom := getEventIfVisible(ctx, rsAPI, parent, userID)
+		if !joinedToRoom {
+			return
+		}
+		err = he.SetUnsignedField(constRoomIDKey, event.RoomID())
+		if err != nil {
+			util.GetLogger(context.Background()).WithError(err).Warn("Failed to SetUnsignedField")
+			return
+		}
+
+		var servers []gomatrixserverlib.ServerName
+		if fsAPI != nil {
+			var res fs.QueryJoinedHostServerNamesInRoomResponse
+			err = fsAPI.QueryJoinedHostServerNamesInRoom(ctx, &fs.QueryJoinedHostServerNamesInRoomRequest{
+				RoomID: event.RoomID(),
+			}, &res)
+			if err != nil {
+				util.GetLogger(context.Background()).WithError(err).Warn("Failed to QueryJoinedHostServerNamesInRoom")
+				return
+			}
+			servers = res.ServerNames
+		} else {
+			servers = []gomatrixserverlib.ServerName{
+				base.Cfg.Global.ServerName,
+			}
+		}
+		err = he.SetUnsignedField(constRoomServers, servers)
+		if err != nil {
+			util.GetLogger(context.Background()).WithError(err).Warn("Failed to SetUnsignedField")
+			return
+		}
+	})
 
 	base.PublicClientAPIMux.Handle("/unstable/event_relationships",
 		httputil.MakeAuthAPI("eventRelationships", userAPI, eventRelationshipHandler(db, rsAPI)),
@@ -264,34 +318,12 @@ func walkThread(
 }
 
 func (rc *reqCtx) getEventIfVisible(eventID string) *gomatrixserverlib.HeaderedEvent {
-	var queryEventsRes roomserver.QueryEventsByIDResponse
-	err := rc.rsAPI.QueryEventsByID(rc.ctx, &roomserver.QueryEventsByIDRequest{
-		EventIDs: []string{eventID},
-	}, &queryEventsRes)
-	if err != nil {
-		util.GetLogger(rc.ctx).WithError(err).Error("getEventIfVisible: failed to QueryEventsByID")
+	event, joinedToRoom := getEventIfVisible(rc.ctx, rc.rsAPI, eventID, rc.userID)
+	if event == nil {
 		return nil
 	}
-	if len(queryEventsRes.Events) == 0 {
-		util.GetLogger(rc.ctx).Infof("event does not exist")
-		return nil // event does not exist
-	}
-	event := queryEventsRes.Events[0]
-
-	// Allow events if the member is in the room
-	// TODO: This does not honour history_visibility
-	// TODO: This does not honour m.room.create content
-	var queryMembershipRes roomserver.QueryMembershipForUserResponse
-	err = rc.rsAPI.QueryMembershipForUser(rc.ctx, &roomserver.QueryMembershipForUserRequest{
-		RoomID: event.RoomID(),
-		UserID: rc.userID,
-	}, &queryMembershipRes)
-	if err != nil {
-		util.GetLogger(rc.ctx).WithError(err).Error("getEventIfVisible: failed to QueryMembershipForUser")
-		return nil
-	}
-	if queryMembershipRes.IsInRoom {
-		return &event
+	if joinedToRoom {
+		return event
 	}
 	if rc.req.AutoJoin {
 		var joinRes roomserver.PerformJoinResponse
@@ -305,12 +337,42 @@ func (rc *reqCtx) getEventIfVisible(eventID string) *gomatrixserverlib.HeaderedE
 			util.GetLogger(rc.ctx).WithError(joinRes.Error).WithField("room_id", event.RoomID()).Error("Failed to auto-join room")
 			return nil
 		}
-		return &event
+		return event
 	}
 	util.GetLogger(rc.ctx).Infof("user not in room and auto_join disabled")
 	return nil
 }
 
+func getEventIfVisible(ctx context.Context, rsAPI roomserver.RoomserverInternalAPI, eventID, userID string) (*gomatrixserverlib.HeaderedEvent, bool) {
+	var queryEventsRes roomserver.QueryEventsByIDResponse
+	err := rsAPI.QueryEventsByID(ctx, &roomserver.QueryEventsByIDRequest{
+		EventIDs: []string{eventID},
+	}, &queryEventsRes)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("getEventIfVisible: failed to QueryEventsByID")
+		return nil, false
+	}
+	if len(queryEventsRes.Events) == 0 {
+		util.GetLogger(ctx).Infof("event does not exist")
+		return nil, false // event does not exist
+	}
+	event := queryEventsRes.Events[0]
+
+	// Allow events if the member is in the room
+	// TODO: This does not honour history_visibility
+	// TODO: This does not honour m.room.create content
+	var queryMembershipRes roomserver.QueryMembershipForUserResponse
+	err = rsAPI.QueryMembershipForUser(ctx, &roomserver.QueryMembershipForUserRequest{
+		RoomID: event.RoomID(),
+		UserID: userID,
+	}, &queryMembershipRes)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("getEventIfVisible: failed to QueryMembershipForUser")
+		return nil, false
+	}
+	return &event, queryMembershipRes.IsInRoom
+}
+
 type walkInfo struct {
 	eventInfo
 	SiblingNumber int

internal/mscs/mscs.go

@@ -35,7 +35,7 @@ func Enable(base *setup.BaseDendrite, monolith *setup.Monolith) error {
 func EnableMSC(base *setup.BaseDendrite, monolith *setup.Monolith, msc string) error {
 	switch msc {
 	case "msc2836":
-		return msc2836.Enable(base, monolith.RoomserverAPI, monolith.UserAPI)
+		return msc2836.Enable(base, monolith.RoomserverAPI, monolith.FederationSenderAPI, monolith.UserAPI)
 	default:
 		return fmt.Errorf("EnableMSC: unknown msc '%s'", msc)
 	}

roomserver/internal/input/input.go

@@ -62,6 +62,7 @@ func (w *inputWorker) start() {
 	for {
 		select {
 		case task := <-w.input:
+			hooks.Run(hooks.KindModifyNewEvent, &task.event.Event)
 			_, task.err = w.r.processRoomEvent(task.ctx, task.event)
 			if task.err == nil {
 				hooks.Run(hooks.KindNewEvent, &task.event.Event)