Add typing notifications to /sync responses - fixes #635 (#718)

This PR adds a new consumer for typing notifications in syncapi. It also brings changes to syncserver.go and some related files so EDUs can better fit in /sync responses.

Fixes #635.
Fixes #574.

syncapi/consumers/clientapi.go

@@ -22,6 +22,7 @@ import (
 	"github.com/matrix-org/dendrite/common/config"
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/sync"
+	"github.com/matrix-org/dendrite/syncapi/types"
 	log "github.com/sirupsen/logrus"
 	sarama "gopkg.in/Shopify/sarama.v1"
 )
@@ -29,7 +30,7 @@ import (
 // OutputClientDataConsumer consumes events that originated in the client API server.
 type OutputClientDataConsumer struct {
 	clientAPIConsumer *common.ContinualConsumer
-	db                *storage.SyncServerDatabase
+	db                *storage.SyncServerDatasource
 	notifier          *sync.Notifier
 }
 
@@ -38,7 +39,7 @@ func NewOutputClientDataConsumer(
 	cfg *config.Dendrite,
 	kafkaConsumer sarama.Consumer,
 	n *sync.Notifier,
-	store *storage.SyncServerDatabase,
+	store *storage.SyncServerDatasource,
 ) *OutputClientDataConsumer {
 
 	consumer := common.ContinualConsumer{
@@ -78,7 +79,7 @@ func (s *OutputClientDataConsumer) onMessage(msg *sarama.ConsumerMessage) error
 		"room_id": output.RoomID,
 	}).Info("received data from client API server")
 
-	syncStreamPos, err := s.db.UpsertAccountData(
+	pduPos, err := s.db.UpsertAccountData(
 		context.TODO(), string(msg.Key), output.RoomID, output.Type,
 	)
 	if err != nil {
@@ -89,7 +90,7 @@ func (s *OutputClientDataConsumer) onMessage(msg *sarama.ConsumerMessage) error
 		}).Panicf("could not save account data")
 	}
 
-	s.notifier.OnNewEvent(nil, string(msg.Key), syncStreamPos)
+	s.notifier.OnNewEvent(nil, "", []string{string(msg.Key)}, types.SyncPosition{PDUPosition: pduPos})
 
 	return nil
 }

syncapi/consumers/roomserver.go

@@ -33,7 +33,7 @@ import (
 // OutputRoomEventConsumer consumes events that originated in the room server.
 type OutputRoomEventConsumer struct {
 	roomServerConsumer *common.ContinualConsumer
-	db                 *storage.SyncServerDatabase
+	db                 *storage.SyncServerDatasource
 	notifier           *sync.Notifier
 	query              api.RoomserverQueryAPI
 }
@@ -43,7 +43,7 @@ func NewOutputRoomEventConsumer(
 	cfg *config.Dendrite,
 	kafkaConsumer sarama.Consumer,
 	n *sync.Notifier,
-	store *storage.SyncServerDatabase,
+	store *storage.SyncServerDatasource,
 	queryAPI api.RoomserverQueryAPI,
 ) *OutputRoomEventConsumer {
 
@@ -126,7 +126,7 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 		}
 	}
 
-	syncStreamPos, err := s.db.WriteEvent(
+	pduPos, err := s.db.WriteEvent(
 		ctx,
 		&ev,
 		addsStateEvents,
@@ -144,7 +144,7 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 		}).Panicf("roomserver output log: write event failure")
 		return nil
 	}
-	s.notifier.OnNewEvent(&ev, "", types.StreamPosition(syncStreamPos))
+	s.notifier.OnNewEvent(&ev, "", nil, types.SyncPosition{PDUPosition: pduPos})
 
 	return nil
 }
@@ -152,7 +152,7 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 func (s *OutputRoomEventConsumer) onNewInviteEvent(
 	ctx context.Context, msg api.OutputNewInviteEvent,
 ) error {
-	syncStreamPos, err := s.db.AddInviteEvent(ctx, msg.Event)
+	pduPos, err := s.db.AddInviteEvent(ctx, msg.Event)
 	if err != nil {
 		// panic rather than continue with an inconsistent database
 		log.WithFields(log.Fields{
@@ -161,7 +161,7 @@ func (s *OutputRoomEventConsumer) onNewInviteEvent(
 		}).Panicf("roomserver output log: write invite failure")
 		return nil
 	}
-	s.notifier.OnNewEvent(&msg.Event, "", syncStreamPos)
+	s.notifier.OnNewEvent(&msg.Event, "", nil, types.SyncPosition{PDUPosition: pduPos})
 	return nil
 }
 

syncapi/consumers/typingserver.go

@@ -0,0 +1,96 @@
+// Copyright 2019 Alex Chen
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package consumers
+
+import (
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/common"
+	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/syncapi/storage"
+	"github.com/matrix-org/dendrite/syncapi/sync"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/dendrite/typingserver/api"
+	log "github.com/sirupsen/logrus"
+	sarama "gopkg.in/Shopify/sarama.v1"
+)
+
+// OutputTypingEventConsumer consumes events that originated in the typing server.
+type OutputTypingEventConsumer struct {
+	typingConsumer *common.ContinualConsumer
+	db             *storage.SyncServerDatasource
+	notifier       *sync.Notifier
+}
+
+// NewOutputTypingEventConsumer creates a new OutputTypingEventConsumer.
+// Call Start() to begin consuming from the typing server.
+func NewOutputTypingEventConsumer(
+	cfg *config.Dendrite,
+	kafkaConsumer sarama.Consumer,
+	n *sync.Notifier,
+	store *storage.SyncServerDatasource,
+) *OutputTypingEventConsumer {
+
+	consumer := common.ContinualConsumer{
+		Topic:          string(cfg.Kafka.Topics.OutputTypingEvent),
+		Consumer:       kafkaConsumer,
+		PartitionStore: store,
+	}
+
+	s := &OutputTypingEventConsumer{
+		typingConsumer: &consumer,
+		db:             store,
+		notifier:       n,
+	}
+
+	consumer.ProcessMessage = s.onMessage
+
+	return s
+}
+
+// Start consuming from typing api
+func (s *OutputTypingEventConsumer) Start() error {
+	s.db.SetTypingTimeoutCallback(func(userID, roomID string, latestSyncPosition int64) {
+		s.notifier.OnNewEvent(nil, roomID, nil, types.SyncPosition{TypingPosition: latestSyncPosition})
+	})
+
+	return s.typingConsumer.Start()
+}
+
+func (s *OutputTypingEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
+	var output api.OutputTypingEvent
+	if err := json.Unmarshal(msg.Value, &output); err != nil {
+		// If the message was invalid, log it and move on to the next message in the stream
+		log.WithError(err).Errorf("typing server output log: message parse failure")
+		return nil
+	}
+
+	log.WithFields(log.Fields{
+		"room_id": output.Event.RoomID,
+		"user_id": output.Event.UserID,
+		"typing":  output.Event.Typing,
+	}).Debug("received data from typing server")
+
+	var typingPos int64
+	typingEvent := output.Event
+	if typingEvent.Typing {
+		typingPos = s.db.AddTypingUser(typingEvent.UserID, typingEvent.RoomID, output.ExpireTime)
+	} else {
+		typingPos = s.db.RemoveTypingUser(typingEvent.UserID, typingEvent.RoomID)
+	}
+
+	s.notifier.OnNewEvent(nil, output.Event.RoomID, nil, types.SyncPosition{TypingPosition: typingPos})
+	return nil
+}

syncapi/routing/routing.go

@@ -34,7 +34,7 @@ const pathPrefixR0 = "/_matrix/client/r0"
 // Due to Setup being used to call many other functions, a gocyclo nolint is
 // applied:
 // nolint: gocyclo
-func Setup(apiMux *mux.Router, srp *sync.RequestPool, syncDB *storage.SyncServerDatabase, deviceDB *devices.Database) {
+func Setup(apiMux *mux.Router, srp *sync.RequestPool, syncDB *storage.SyncServerDatasource, deviceDB *devices.Database) {
 	r0mux := apiMux.PathPrefix(pathPrefixR0).Subrouter()
 
 	authData := auth.Data{

syncapi/routing/state.go

@@ -40,7 +40,7 @@ type stateEventInStateResp struct {
 // TODO: Check if the user is in the room. If not, check if the room's history
 // is publicly visible. Current behaviour is returning an empty array if the
 // user cannot see the room's history.
-func OnIncomingStateRequest(req *http.Request, db *storage.SyncServerDatabase, roomID string) util.JSONResponse {
+func OnIncomingStateRequest(req *http.Request, db *storage.SyncServerDatasource, roomID string) util.JSONResponse {
 	// TODO(#287): Auth request and handle the case where the user has left (where
 	// we should return the state at the poin they left)
 
@@ -84,7 +84,7 @@ func OnIncomingStateRequest(req *http.Request, db *storage.SyncServerDatabase, r
 // /rooms/{roomID}/state/{type}/{statekey} request. It will look in current
 // state to see if there is an event with that type and state key, if there
 // is then (by default) we return the content, otherwise a 404.
-func OnIncomingStateTypeRequest(req *http.Request, db *storage.SyncServerDatabase, roomID string, evType, stateKey string) util.JSONResponse {
+func OnIncomingStateTypeRequest(req *http.Request, db *storage.SyncServerDatasource, roomID string, evType, stateKey string) util.JSONResponse {
 	// TODO(#287): Auth request and handle the case where the user has left (where
 	// we should return the state at the poin they left)
 

syncapi/storage/account_data_table.go

@@ -19,8 +19,6 @@ import (
 	"database/sql"
 
 	"github.com/matrix-org/dendrite/common"
-
-	"github.com/matrix-org/dendrite/syncapi/types"
 )
 
 const accountDataSchema = `
@@ -94,7 +92,7 @@ func (s *accountDataStatements) insertAccountData(
 func (s *accountDataStatements) selectAccountDataInRange(
 	ctx context.Context,
 	userID string,
-	oldPos, newPos types.StreamPosition,
+	oldPos, newPos int64,
 ) (data map[string][]string, err error) {
 	data = make(map[string][]string)
 

syncapi/storage/output_room_events_table.go

@@ -23,7 +23,6 @@ import (
 
 	"github.com/lib/pq"
 	"github.com/matrix-org/dendrite/common"
-	"github.com/matrix-org/dendrite/syncapi/types"
 	"github.com/matrix-org/gomatrixserverlib"
 	log "github.com/sirupsen/logrus"
 )
@@ -109,11 +108,11 @@ func (s *outputRoomEventsStatements) prepare(db *sql.DB) (err error) {
 	return
 }
 
-// selectStateInRange returns the state events between the two given stream positions, exclusive of oldPos, inclusive of newPos.
+// selectStateInRange returns the state events between the two given PDU stream positions, exclusive of oldPos, inclusive of newPos.
 // Results are bucketed based on the room ID. If the same state is overwritten multiple times between the
 // two positions, only the most recent state is returned.
 func (s *outputRoomEventsStatements) selectStateInRange(
-	ctx context.Context, txn *sql.Tx, oldPos, newPos types.StreamPosition,
+	ctx context.Context, txn *sql.Tx, oldPos, newPos int64,
 ) (map[string]map[string]bool, map[string]streamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectStateInRangeStmt)
 
@@ -171,7 +170,7 @@ func (s *outputRoomEventsStatements) selectStateInRange(
 
 		eventIDToEvent[ev.EventID()] = streamEvent{
 			Event:          ev,
-			streamPosition: types.StreamPosition(streamPos),
+			streamPosition: streamPos,
 		}
 	}
 
@@ -223,7 +222,7 @@ func (s *outputRoomEventsStatements) insertEvent(
 // RecentEventsInRoom returns the most recent events in the given room, up to a maximum of 'limit'.
 func (s *outputRoomEventsStatements) selectRecentEvents(
 	ctx context.Context, txn *sql.Tx,
-	roomID string, fromPos, toPos types.StreamPosition, limit int,
+	roomID string, fromPos, toPos int64, limit int,
 ) ([]streamEvent, error) {
 	stmt := common.TxStmt(txn, s.selectRecentEventsStmt)
 	rows, err := stmt.QueryContext(ctx, roomID, fromPos, toPos, limit)
@@ -286,7 +285,7 @@ func rowsToStreamEvents(rows *sql.Rows) ([]streamEvent, error) {
 
 		result = append(result, streamEvent{
 			Event:          ev,
-			streamPosition: types.StreamPosition(streamPos),
+			streamPosition: streamPos,
 			transactionID:  transactionID,
 		})
 	}

syncapi/storage/syncserver.go

@@ -17,7 +17,10 @@ package storage
 import (
 	"context"
 	"database/sql"
+	"encoding/json"
 	"fmt"
+	"strconv"
+	"time"
 
 	"github.com/sirupsen/logrus"
 
@@ -28,6 +31,7 @@ import (
 	_ "github.com/lib/pq"
 	"github.com/matrix-org/dendrite/common"
 	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/dendrite/typingserver/cache"
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
@@ -35,33 +39,35 @@ type stateDelta struct {
 	roomID      string
 	stateEvents []gomatrixserverlib.Event
 	membership  string
-	// The stream position of the latest membership event for this user, if applicable.
+	// The PDU stream position of the latest membership event for this user, if applicable.
 	// Can be 0 if there is no membership event in this delta.
-	membershipPos types.StreamPosition
+	membershipPos int64
 }
 
-// Same as gomatrixserverlib.Event but also has the stream position for this event.
+// Same as gomatrixserverlib.Event but also has the PDU stream position for this event.
 type streamEvent struct {
 	gomatrixserverlib.Event
-	streamPosition types.StreamPosition
+	streamPosition int64
 	transactionID  *api.TransactionID
 }
 
-// SyncServerDatabase represents a sync server database
+// SyncServerDatabase represents a sync server datasource which manages
-type SyncServerDatabase struct {
+// both the database for PDUs and caches for EDUs.
+type SyncServerDatasource struct {
 	db *sql.DB
 	common.PartitionOffsetStatements
 	accountData accountDataStatements
 	events      outputRoomEventsStatements
 	roomstate   currentRoomStateStatements
 	invites     inviteEventsStatements
+	typingCache *cache.TypingCache
 }
 
 // NewSyncServerDatabase creates a new sync server database
-func NewSyncServerDatabase(dataSourceName string) (*SyncServerDatabase, error) {
+func NewSyncServerDatasource(dbDataSourceName string) (*SyncServerDatasource, error) {
-	var d SyncServerDatabase
+	var d SyncServerDatasource
 	var err error
-	if d.db, err = sql.Open("postgres", dataSourceName); err != nil {
+	if d.db, err = sql.Open("postgres", dbDataSourceName); err != nil {
 		return nil, err
 	}
 	if err = d.PartitionOffsetStatements.Prepare(d.db, "syncapi"); err != nil {
@@ -79,11 +85,12 @@ func NewSyncServerDatabase(dataSourceName string) (*SyncServerDatabase, error) {
 	if err := d.invites.prepare(d.db); err != nil {
 		return nil, err
 	}
+	d.typingCache = cache.NewTypingCache()
 	return &d, nil
 }
 
 // AllJoinedUsersInRooms returns a map of room ID to a list of all joined user IDs.
-func (d *SyncServerDatabase) AllJoinedUsersInRooms(ctx context.Context) (map[string][]string, error) {
+func (d *SyncServerDatasource) AllJoinedUsersInRooms(ctx context.Context) (map[string][]string, error) {
 	return d.roomstate.selectJoinedUsers(ctx)
 }
 
@@ -92,7 +99,7 @@ func (d *SyncServerDatabase) AllJoinedUsersInRooms(ctx context.Context) (map[str
 // If an event is not found in the database then it will be omitted from the list.
 // Returns an error if there was a problem talking with the database.
 // Does not include any transaction IDs in the returned events.
-func (d *SyncServerDatabase) Events(ctx context.Context, eventIDs []string) ([]gomatrixserverlib.Event, error) {
+func (d *SyncServerDatasource) Events(ctx context.Context, eventIDs []string) ([]gomatrixserverlib.Event, error) {
 	streamEvents, err := d.events.selectEvents(ctx, nil, eventIDs)
 	if err != nil {
 		return nil, err
@@ -104,38 +111,38 @@ func (d *SyncServerDatabase) Events(ctx context.Context, eventIDs []string) ([]g
 }
 
 // WriteEvent into the database. It is not safe to call this function from multiple goroutines, as it would create races
-// when generating the stream position for this event. Returns the sync stream position for the inserted event.
+// when generating the sync stream position for this event. Returns the sync stream position for the inserted event.
 // Returns an error if there was a problem inserting this event.
-func (d *SyncServerDatabase) WriteEvent(
+func (d *SyncServerDatasource) WriteEvent(
 	ctx context.Context,
 	ev *gomatrixserverlib.Event,
 	addStateEvents []gomatrixserverlib.Event,
 	addStateEventIDs, removeStateEventIDs []string,
 	transactionID *api.TransactionID,
-) (streamPos types.StreamPosition, returnErr error) {
+) (pduPosition int64, returnErr error) {
 	returnErr = common.WithTransaction(d.db, func(txn *sql.Tx) error {
 		var err error
 		pos, err := d.events.insertEvent(ctx, txn, ev, addStateEventIDs, removeStateEventIDs, transactionID)
 		if err != nil {
 			return err
 		}
-		streamPos = types.StreamPosition(pos)
+		pduPosition = pos
 
 		if len(addStateEvents) == 0 && len(removeStateEventIDs) == 0 {
 			// Nothing to do, the event may have just been a message event.
 			return nil
 		}
 
-		return d.updateRoomState(ctx, txn, removeStateEventIDs, addStateEvents, streamPos)
+		return d.updateRoomState(ctx, txn, removeStateEventIDs, addStateEvents, pduPosition)
 	})
 	return
 }
 
-func (d *SyncServerDatabase) updateRoomState(
+func (d *SyncServerDatasource) updateRoomState(
 	ctx context.Context, txn *sql.Tx,
 	removedEventIDs []string,
 	addedEvents []gomatrixserverlib.Event,
-	streamPos types.StreamPosition,
+	pduPosition int64,
 ) error {
 	// remove first, then add, as we do not ever delete state, but do replace state which is a remove followed by an add.
 	for _, eventID := range removedEventIDs {
@@ -157,7 +164,7 @@ func (d *SyncServerDatabase) updateRoomState(
 			}
 			membership = &value
 		}
-		if err := d.roomstate.upsertRoomState(ctx, txn, event, membership, int64(streamPos)); err != nil {
+		if err := d.roomstate.upsertRoomState(ctx, txn, event, membership, pduPosition); err != nil {
 			return err
 		}
 	}
@@ -168,7 +175,7 @@ func (d *SyncServerDatabase) updateRoomState(
 // GetStateEvent returns the Matrix state event of a given type for a given room with a given state key
 // If no event could be found, returns nil
 // If there was an issue during the retrieval, returns an error
-func (d *SyncServerDatabase) GetStateEvent(
+func (d *SyncServerDatasource) GetStateEvent(
 	ctx context.Context, roomID, evType, stateKey string,
 ) (*gomatrixserverlib.Event, error) {
 	return d.roomstate.selectStateEvent(ctx, roomID, evType, stateKey)
@@ -177,7 +184,7 @@ func (d *SyncServerDatabase) GetStateEvent(
 // GetStateEventsForRoom fetches the state events for a given room.
 // Returns an empty slice if no state events could be found for this room.
 // Returns an error if there was an issue with the retrieval.
-func (d *SyncServerDatabase) GetStateEventsForRoom(
+func (d *SyncServerDatasource) GetStateEventsForRoom(
 	ctx context.Context, roomID string,
 ) (stateEvents []gomatrixserverlib.Event, err error) {
 	err = common.WithTransaction(d.db, func(txn *sql.Tx) error {
@@ -187,46 +194,49 @@ func (d *SyncServerDatabase) GetStateEventsForRoom(
 	return
 }
 
-// SyncStreamPosition returns the latest position in the sync stream. Returns 0 if there are no events yet.
+// SyncPosition returns the latest positions for syncing.
-func (d *SyncServerDatabase) SyncStreamPosition(ctx context.Context) (types.StreamPosition, error) {
+func (d *SyncServerDatasource) SyncPosition(ctx context.Context) (types.SyncPosition, error) {
-	return d.syncStreamPositionTx(ctx, nil)
+	return d.syncPositionTx(ctx, nil)
 }
 
-func (d *SyncServerDatabase) syncStreamPositionTx(
+func (d *SyncServerDatasource) syncPositionTx(
 	ctx context.Context, txn *sql.Tx,
-) (types.StreamPosition, error) {
+) (sp types.SyncPosition, err error) {
-	maxID, err := d.events.selectMaxEventID(ctx, txn)
+
+	maxEventID, err := d.events.selectMaxEventID(ctx, txn)
 	if err != nil {
-		return 0, err
+		return sp, err
 	}
 	maxAccountDataID, err := d.accountData.selectMaxAccountDataID(ctx, txn)
 	if err != nil {
-		return 0, err
+		return sp, err
 	}
-	if maxAccountDataID > maxID {
+	if maxAccountDataID > maxEventID {
-		maxID = maxAccountDataID
+		maxEventID = maxAccountDataID
 	}
 	maxInviteID, err := d.invites.selectMaxInviteID(ctx, txn)
 	if err != nil {
-		return 0, err
+		return sp, err
 	}
-	if maxInviteID > maxID {
+	if maxInviteID > maxEventID {
-		maxID = maxInviteID
+		maxEventID = maxInviteID
 	}
-	return types.StreamPosition(maxID), nil
+	sp.PDUPosition = maxEventID
+
+	sp.TypingPosition = d.typingCache.GetLatestSyncPosition()
+
+	return
 }
 
-// IncrementalSync returns all the data needed in order to create an incremental
+// addPDUDeltaToResponse adds all PDU deltas to a sync response.
-// sync response for the given user. Events returned will include any client
+// IDs of all rooms the user joined are returned so EDU deltas can be added for them.
-// transaction IDs associated with the given device. These transaction IDs come
+func (d *SyncServerDatasource) addPDUDeltaToResponse(
-// from when the device sent the event via an API that included a transaction
-// ID.
-func (d *SyncServerDatabase) IncrementalSync(
 	ctx context.Context,
 	device authtypes.Device,
-	fromPos, toPos types.StreamPosition,
+	fromPos, toPos int64,
 	numRecentEventsPerRoom int,
-) (*types.Response, error) {
+	res *types.Response,
+) ([]string, error) {
 	txn, err := d.db.BeginTx(ctx, &txReadOnlySnapshot)
 	if err != nil {
 		return nil, err
@@ -235,7 +245,7 @@ func (d *SyncServerDatabase) IncrementalSync(
 	defer common.EndTransaction(txn, &succeeded)
 
 	// Work out which rooms to return in the response. This is done by getting not only the currently
-	// joined rooms, but also which rooms have membership transitions for this user between the 2 stream positions.
+	// joined rooms, but also which rooms have membership transitions for this user between the 2 PDU stream positions.
 	// This works out what the 'state' key should be for each room as well as which membership block
 	// to put the room into.
 	deltas, err := d.getStateDeltas(ctx, &device, txn, fromPos, toPos, device.UserID)
@@ -243,8 +253,9 @@ func (d *SyncServerDatabase) IncrementalSync(
 		return nil, err
 	}
 
-	res := types.NewResponse(toPos)
+	joinedRoomIDs := make([]string, 0, len(deltas))
 	for _, delta := range deltas {
+		joinedRoomIDs = append(joinedRoomIDs, delta.roomID)
 		err = d.addRoomDeltaToResponse(ctx, &device, txn, fromPos, toPos, delta, numRecentEventsPerRoom, res)
 		if err != nil {
 			return nil, err
@@ -257,52 +268,151 @@ func (d *SyncServerDatabase) IncrementalSync(
 	}
 
 	succeeded = true
+	return joinedRoomIDs, nil
+}
+
+// addTypingDeltaToResponse adds all typing notifications to a sync response
+// since the specified position.
+func (d *SyncServerDatasource) addTypingDeltaToResponse(
+	since int64,
+	joinedRoomIDs []string,
+	res *types.Response,
+) error {
+	var jr types.JoinResponse
+	var ok bool
+	var err error
+	for _, roomID := range joinedRoomIDs {
+		if typingUsers, updated := d.typingCache.GetTypingUsersIfUpdatedAfter(
+			roomID, since,
+		); updated {
+			ev := gomatrixserverlib.ClientEvent{
+				Type: gomatrixserverlib.MTyping,
+			}
+			ev.Content, err = json.Marshal(map[string]interface{}{
+				"user_ids": typingUsers,
+			})
+			if err != nil {
+				return err
+			}
+
+			if jr, ok = res.Rooms.Join[roomID]; !ok {
+				jr = *types.NewJoinResponse()
+			}
+			jr.Ephemeral.Events = append(jr.Ephemeral.Events, ev)
+			res.Rooms.Join[roomID] = jr
+		}
+	}
+	return nil
+}
+
+// addEDUDeltaToResponse adds updates for EDUs of each type since fromPos if
+// the positions of that type are not equal in fromPos and toPos.
+func (d *SyncServerDatasource) addEDUDeltaToResponse(
+	fromPos, toPos types.SyncPosition,
+	joinedRoomIDs []string,
+	res *types.Response,
+) (err error) {
+
+	if fromPos.TypingPosition != toPos.TypingPosition {
+		err = d.addTypingDeltaToResponse(
+			fromPos.TypingPosition, joinedRoomIDs, res,
+		)
+	}
+
+	return
+}
+
+// IncrementalSync returns all the data needed in order to create an incremental
+// sync response for the given user. Events returned will include any client
+// transaction IDs associated with the given device. These transaction IDs come
+// from when the device sent the event via an API that included a transaction
+// ID.
+func (d *SyncServerDatasource) IncrementalSync(
+	ctx context.Context,
+	device authtypes.Device,
+	fromPos, toPos types.SyncPosition,
+	numRecentEventsPerRoom int,
+) (*types.Response, error) {
+	nextBatchPos := fromPos.WithUpdates(toPos)
+	res := types.NewResponse(nextBatchPos)
+
+	var joinedRoomIDs []string
+	var err error
+	if fromPos.PDUPosition != toPos.PDUPosition {
+		joinedRoomIDs, err = d.addPDUDeltaToResponse(
+			ctx, device, fromPos.PDUPosition, toPos.PDUPosition, numRecentEventsPerRoom, res,
+		)
+	} else {
+		joinedRoomIDs, err = d.roomstate.selectRoomIDsWithMembership(
+			ctx, nil, device.UserID, "join",
+		)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	err = d.addEDUDeltaToResponse(
+		fromPos, toPos, joinedRoomIDs, res,
+	)
+	if err != nil {
+		return nil, err
+	}
+
 	return res, nil
 }
 
-// CompleteSync a complete /sync API response for the given user.
+// getResponseWithPDUsForCompleteSync creates a response and adds all PDUs needed
-func (d *SyncServerDatabase) CompleteSync(
+// to it. It returns toPos and joinedRoomIDs for use of adding EDUs.
-	ctx context.Context, userID string, numRecentEventsPerRoom int,
+func (d *SyncServerDatasource) getResponseWithPDUsForCompleteSync(
-) (*types.Response, error) {
+	ctx context.Context,
+	userID string,
+	numRecentEventsPerRoom int,
+) (
+	res *types.Response,
+	toPos types.SyncPosition,
+	joinedRoomIDs []string,
+	err error,
+) {
 	// This needs to be all done in a transaction as we need to do multiple SELECTs, and we need to have
-	// a consistent view of the database throughout. This includes extracting the sync stream position.
+	// a consistent view of the database throughout. This includes extracting the sync position.
 	// This does have the unfortunate side-effect that all the matrixy logic resides in this function,
 	// but it's better to not hide the fact that this is being done in a transaction.
 	txn, err := d.db.BeginTx(ctx, &txReadOnlySnapshot)
 	if err != nil {
-		return nil, err
+		return
 	}
 	var succeeded bool
 	defer common.EndTransaction(txn, &succeeded)
 
-	// Get the current stream position which we will base the sync response on.
+	// Get the current sync position which we will base the sync response on.
-	pos, err := d.syncStreamPositionTx(ctx, txn)
+	toPos, err = d.syncPositionTx(ctx, txn)
 	if err != nil {
-		return nil, err
+		return
 	}
 
+	res = types.NewResponse(toPos)
+
 	// Extract room state and recent events for all rooms the user is joined to.
-	roomIDs, err := d.roomstate.selectRoomIDsWithMembership(ctx, txn, userID, "join")
+	joinedRoomIDs, err = d.roomstate.selectRoomIDsWithMembership(ctx, txn, userID, "join")
 	if err != nil {
-		return nil, err
+		return
 	}
 
 	// Build up a /sync response. Add joined rooms.
-	res := types.NewResponse(pos)
+	for _, roomID := range joinedRoomIDs {
-	for _, roomID := range roomIDs {
 		var stateEvents []gomatrixserverlib.Event
 		stateEvents, err = d.roomstate.selectCurrentState(ctx, txn, roomID)
 		if err != nil {
-			return nil, err
+			return
 		}
 		// TODO: When filters are added, we may need to call this multiple times to get enough events.
 		//       See: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L316
 		var recentStreamEvents []streamEvent
 		recentStreamEvents, err = d.events.selectRecentEvents(
-			ctx, txn, roomID, types.StreamPosition(0), pos, numRecentEventsPerRoom,
+			ctx, txn, roomID, 0, toPos.PDUPosition, numRecentEventsPerRoom,
 		)
 		if err != nil {
-			return nil, err
+			return
 		}
 
 		// We don't include a device here as we don't need to send down
@@ -311,10 +421,12 @@ func (d *SyncServerDatabase) CompleteSync(
 
 		stateEvents = removeDuplicates(stateEvents, recentEvents)
 		jr := types.NewJoinResponse()
-		if prevBatch := recentStreamEvents[0].streamPosition - 1; prevBatch > 0 {
+		if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
-			jr.Timeline.PrevBatch = types.StreamPosition(prevBatch).String()
+			// Use the short form of batch token for prev_batch
+			jr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
 		} else {
-			jr.Timeline.PrevBatch = types.StreamPosition(1).String()
+			// Use the short form of batch token for prev_batch
+			jr.Timeline.PrevBatch = "1"
 		}
 		jr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		jr.Timeline.Limited = true
@@ -322,12 +434,34 @@ func (d *SyncServerDatabase) CompleteSync(
 		res.Rooms.Join[roomID] = *jr
 	}
 
-	if err = d.addInvitesToResponse(ctx, txn, userID, 0, pos, res); err != nil {
+	if err = d.addInvitesToResponse(ctx, txn, userID, 0, toPos.PDUPosition, res); err != nil {
-		return nil, err
+		return
 	}
 
 	succeeded = true
-	return res, err
+	return res, toPos, joinedRoomIDs, err
+}
+
+// CompleteSync returns a complete /sync API response for the given user.
+func (d *SyncServerDatasource) CompleteSync(
+	ctx context.Context, userID string, numRecentEventsPerRoom int,
+) (*types.Response, error) {
+	res, toPos, joinedRoomIDs, err := d.getResponseWithPDUsForCompleteSync(
+		ctx, userID, numRecentEventsPerRoom,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	// Use a zero value SyncPosition for fromPos so all EDU states are added.
+	err = d.addEDUDeltaToResponse(
+		types.SyncPosition{}, toPos, joinedRoomIDs, res,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return res, nil
 }
 
 var txReadOnlySnapshot = sql.TxOptions{
@@ -345,8 +479,8 @@ var txReadOnlySnapshot = sql.TxOptions{
 // Returns a map following the format data[roomID] = []dataTypes
 // If no data is retrieved, returns an empty map
 // If there was an issue with the retrieval, returns an error
-func (d *SyncServerDatabase) GetAccountDataInRange(
+func (d *SyncServerDatasource) GetAccountDataInRange(
-	ctx context.Context, userID string, oldPos, newPos types.StreamPosition,
+	ctx context.Context, userID string, oldPos, newPos int64,
 ) (map[string][]string, error) {
 	return d.accountData.selectAccountDataInRange(ctx, userID, oldPos, newPos)
 }
@@ -357,26 +491,24 @@ func (d *SyncServerDatabase) GetAccountDataInRange(
 // If no data with the given type, user ID and room ID exists in the database,
 // creates a new row, else update the existing one
 // Returns an error if there was an issue with the upsert
-func (d *SyncServerDatabase) UpsertAccountData(
+func (d *SyncServerDatasource) UpsertAccountData(
 	ctx context.Context, userID, roomID, dataType string,
-) (types.StreamPosition, error) {
+) (int64, error) {
-	pos, err := d.accountData.insertAccountData(ctx, userID, roomID, dataType)
+	return d.accountData.insertAccountData(ctx, userID, roomID, dataType)
-	return types.StreamPosition(pos), err
 }
 
 // AddInviteEvent stores a new invite event for a user.
 // If the invite was successfully stored this returns the stream ID it was stored at.
 // Returns an error if there was a problem communicating with the database.
-func (d *SyncServerDatabase) AddInviteEvent(
+func (d *SyncServerDatasource) AddInviteEvent(
 	ctx context.Context, inviteEvent gomatrixserverlib.Event,
-) (types.StreamPosition, error) {
+) (int64, error) {
-	pos, err := d.invites.insertInviteEvent(ctx, inviteEvent)
+	return d.invites.insertInviteEvent(ctx, inviteEvent)
-	return types.StreamPosition(pos), err
 }
 
 // RetireInviteEvent removes an old invite event from the database.
 // Returns an error if there was a problem communicating with the database.
-func (d *SyncServerDatabase) RetireInviteEvent(
+func (d *SyncServerDatasource) RetireInviteEvent(
 	ctx context.Context, inviteEventID string,
 ) error {
 	// TODO: Record that invite has been retired in a stream so that we can
@@ -385,10 +517,30 @@ func (d *SyncServerDatabase) RetireInviteEvent(
 	return err
 }
 
-func (d *SyncServerDatabase) addInvitesToResponse(
+func (d *SyncServerDatasource) SetTypingTimeoutCallback(fn cache.TimeoutCallbackFn) {
+	d.typingCache.SetTimeoutCallback(fn)
+}
+
+// AddTypingUser adds a typing user to the typing cache.
+// Returns the newly calculated sync position for typing notifications.
+func (d *SyncServerDatasource) AddTypingUser(
+	userID, roomID string, expireTime *time.Time,
+) int64 {
+	return d.typingCache.AddTypingUser(userID, roomID, expireTime)
+}
+
+// RemoveTypingUser removes a typing user from the typing cache.
+// Returns the newly calculated sync position for typing notifications.
+func (d *SyncServerDatasource) RemoveTypingUser(
+	userID, roomID string,
+) int64 {
+	return d.typingCache.RemoveUser(userID, roomID)
+}
+
+func (d *SyncServerDatasource) addInvitesToResponse(
 	ctx context.Context, txn *sql.Tx,
 	userID string,
-	fromPos, toPos types.StreamPosition,
+	fromPos, toPos int64,
 	res *types.Response,
 ) error {
 	invites, err := d.invites.selectInviteEventsInRange(
@@ -409,11 +561,11 @@ func (d *SyncServerDatabase) addInvitesToResponse(
 }
 
 // addRoomDeltaToResponse adds a room state delta to a sync response
-func (d *SyncServerDatabase) addRoomDeltaToResponse(
+func (d *SyncServerDatasource) addRoomDeltaToResponse(
 	ctx context.Context,
 	device *authtypes.Device,
 	txn *sql.Tx,
-	fromPos, toPos types.StreamPosition,
+	fromPos, toPos int64,
 	delta stateDelta,
 	numRecentEventsPerRoom int,
 	res *types.Response,
@@ -445,10 +597,12 @@ func (d *SyncServerDatabase) addRoomDeltaToResponse(
 	switch delta.membership {
 	case "join":
 		jr := types.NewJoinResponse()
-		if prevBatch := recentStreamEvents[0].streamPosition - 1; prevBatch > 0 {
+		if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
-			jr.Timeline.PrevBatch = types.StreamPosition(prevBatch).String()
+			// Use the short form of batch token for prev_batch
+			jr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
 		} else {
-			jr.Timeline.PrevBatch = types.StreamPosition(1).String()
+			// Use the short form of batch token for prev_batch
+			jr.Timeline.PrevBatch = "1"
 		}
 		jr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		jr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
@@ -460,10 +614,12 @@ func (d *SyncServerDatabase) addRoomDeltaToResponse(
 		// TODO: recentEvents may contain events that this user is not allowed to see because they are
 		//       no longer in the room.
 		lr := types.NewLeaveResponse()
-		if prevBatch := recentStreamEvents[0].streamPosition - 1; prevBatch > 0 {
+		if prevPDUPos := recentStreamEvents[0].streamPosition - 1; prevPDUPos > 0 {
-			lr.Timeline.PrevBatch = types.StreamPosition(prevBatch).String()
+			// Use the short form of batch token for prev_batch
+			lr.Timeline.PrevBatch = strconv.FormatInt(prevPDUPos, 10)
 		} else {
-			lr.Timeline.PrevBatch = types.StreamPosition(1).String()
+			// Use the short form of batch token for prev_batch
+			lr.Timeline.PrevBatch = "1"
 		}
 		lr.Timeline.Events = gomatrixserverlib.ToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		lr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
@@ -476,7 +632,7 @@ func (d *SyncServerDatabase) addRoomDeltaToResponse(
 
 // fetchStateEvents converts the set of event IDs into a set of events. It will fetch any which are missing from the database.
 // Returns a map of room ID to list of events.
-func (d *SyncServerDatabase) fetchStateEvents(
+func (d *SyncServerDatasource) fetchStateEvents(
 	ctx context.Context, txn *sql.Tx,
 	roomIDToEventIDSet map[string]map[string]bool,
 	eventIDToEvent map[string]streamEvent,
@@ -521,7 +677,7 @@ func (d *SyncServerDatabase) fetchStateEvents(
 	return stateBetween, nil
 }
 
-func (d *SyncServerDatabase) fetchMissingStateEvents(
+func (d *SyncServerDatasource) fetchMissingStateEvents(
 	ctx context.Context, txn *sql.Tx, eventIDs []string,
 ) ([]streamEvent, error) {
 	// Fetch from the events table first so we pick up the stream ID for the
@@ -560,9 +716,9 @@ func (d *SyncServerDatabase) fetchMissingStateEvents(
 	return events, nil
 }
 
-func (d *SyncServerDatabase) getStateDeltas(
+func (d *SyncServerDatasource) getStateDeltas(
 	ctx context.Context, device *authtypes.Device, txn *sql.Tx,
-	fromPos, toPos types.StreamPosition, userID string,
+	fromPos, toPos int64, userID string,
 ) ([]stateDelta, error) {
 	// Implement membership change algorithm: https://github.com/matrix-org/synapse/blob/v0.19.3/synapse/handlers/sync.py#L821
 	// - Get membership list changes for this user in this sync response
@@ -601,7 +757,7 @@ func (d *SyncServerDatabase) getStateDeltas(
 					}
 					s := make([]streamEvent, len(allState))
 					for i := 0; i < len(s); i++ {
-						s[i] = streamEvent{Event: allState[i], streamPosition: types.StreamPosition(0)}
+						s[i] = streamEvent{Event: allState[i], streamPosition: 0}
 					}
 					state[roomID] = s
 					continue // we'll add this room in when we do joined rooms

syncapi/sync/notifier.go

@@ -26,7 +26,7 @@ import (
 )
 
 // Notifier will wake up sleeping requests when there is some new data.
-// It does not tell requests what that data is, only the stream position which
+// It does not tell requests what that data is, only the sync position which
 // they can use to get at it. This is done to prevent races whereby we tell the caller
 // the event, but the token has already advanced by the time they fetch it, resulting
 // in missed events.
@@ -35,18 +35,18 @@ type Notifier struct {
 	roomIDToJoinedUsers map[string]userIDSet
 	// Protects currPos and userStreams.
 	streamLock *sync.Mutex
-	// The latest sync stream position
+	// The latest sync position
-	currPos types.StreamPosition
+	currPos types.SyncPosition
 	// A map of user_id => UserStream which can be used to wake a given user's /sync request.
 	userStreams map[string]*UserStream
 	// The last time we cleaned out stale entries from the userStreams map
 	lastCleanUpTime time.Time
 }
 
-// NewNotifier creates a new notifier set to the given stream position.
+// NewNotifier creates a new notifier set to the given sync position.
 // In order for this to be of any use, the Notifier needs to be told all rooms and
 // the joined users within each of them by calling Notifier.Load(*storage.SyncServerDatabase).
-func NewNotifier(pos types.StreamPosition) *Notifier {
+func NewNotifier(pos types.SyncPosition) *Notifier {
 	return &Notifier{
 		currPos:             pos,
 		roomIDToJoinedUsers: make(map[string]userIDSet),
@@ -58,20 +58,30 @@ func NewNotifier(pos types.StreamPosition) *Notifier {
 
 // OnNewEvent is called when a new event is received from the room server. Must only be
 // called from a single goroutine, to avoid races between updates which could set the
-// current position in the stream incorrectly.
+// current sync position incorrectly.
-// Can be called either with a *gomatrixserverlib.Event, or with an user ID
+// Chooses which user sync streams to update by a provided *gomatrixserverlib.Event
-func (n *Notifier) OnNewEvent(ev *gomatrixserverlib.Event, userID string, pos types.StreamPosition) {
+// (based on the users in the event's room),
+// a roomID directly, or a list of user IDs, prioritised by parameter ordering.
+// posUpdate contains the latest position(s) for one or more types of events.
+// If a position in posUpdate is 0, it means no updates are available of that type.
+// Typically a consumer supplies a posUpdate with the latest sync position for the
+// event type it handles, leaving other fields as 0.
+func (n *Notifier) OnNewEvent(
+	ev *gomatrixserverlib.Event, roomID string, userIDs []string,
+	posUpdate types.SyncPosition,
+) {
 	// update the current position then notify relevant /sync streams.
 	// This needs to be done PRIOR to waking up users as they will read this value.
 	n.streamLock.Lock()
 	defer n.streamLock.Unlock()
-	n.currPos = pos
+	latestPos := n.currPos.WithUpdates(posUpdate)
+	n.currPos = latestPos
 
 	n.removeEmptyUserStreams()
 
 	if ev != nil {
 		// Map this event's room_id to a list of joined users, and wake them up.
-		userIDs := n.joinedUsers(ev.RoomID())
+		usersToNotify := n.joinedUsers(ev.RoomID())
 		// If this is an invite, also add in the invitee to this list.
 		if ev.Type() == "m.room.member" && ev.StateKey() != nil {
 			targetUserID := *ev.StateKey()
@@ -84,11 +94,11 @@ func (n *Notifier) OnNewEvent(ev *gomatrixserverlib.Event, userID string, pos ty
 				// Keep the joined user map up-to-date
 				switch membership {
 				case "invite":
-					userIDs = append(userIDs, targetUserID)
+					usersToNotify = append(usersToNotify, targetUserID)
 				case "join":
 					// Manually append the new user's ID so they get notified
 					// along all members in the room
-					userIDs = append(userIDs, targetUserID)
+					usersToNotify = append(usersToNotify, targetUserID)
 					n.addJoinedUser(ev.RoomID(), targetUserID)
 				case "leave":
 					fallthrough
@@ -98,11 +108,15 @@ func (n *Notifier) OnNewEvent(ev *gomatrixserverlib.Event, userID string, pos ty
 			}
 		}
 
-		for _, toNotifyUserID := range userIDs {
+		n.wakeupUsers(usersToNotify, latestPos)
-			n.wakeupUser(toNotifyUserID, pos)
+	} else if roomID != "" {
-		}
+		n.wakeupUsers(n.joinedUsers(roomID), latestPos)
-	} else if len(userID) > 0 {
+	} else if len(userIDs) > 0 {
-		n.wakeupUser(userID, pos)
+		n.wakeupUsers(userIDs, latestPos)
+	} else {
+		log.WithFields(log.Fields{
+			"posUpdate": posUpdate.String,
+		}).Warn("Notifier.OnNewEvent called but caller supplied no user to wake up")
 	}
 }
 
@@ -127,7 +141,7 @@ func (n *Notifier) GetListener(req syncRequest) UserStreamListener {
 }
 
 // Load the membership states required to notify users correctly.
-func (n *Notifier) Load(ctx context.Context, db *storage.SyncServerDatabase) error {
+func (n *Notifier) Load(ctx context.Context, db *storage.SyncServerDatasource) error {
 	roomToUsers, err := db.AllJoinedUsersInRooms(ctx)
 	if err != nil {
 		return err
@@ -136,8 +150,11 @@ func (n *Notifier) Load(ctx context.Context, db *storage.SyncServerDatabase) err
 	return nil
 }
 
-// CurrentPosition returns the current stream position
+// CurrentPosition returns the current sync position
-func (n *Notifier) CurrentPosition() types.StreamPosition {
+func (n *Notifier) CurrentPosition() types.SyncPosition {
+	n.streamLock.Lock()
+	defer n.streamLock.Unlock()
+
 	return n.currPos
 }
 
@@ -156,12 +173,13 @@ func (n *Notifier) setUsersJoinedToRooms(roomIDToUserIDs map[string][]string) {
 	}
 }
 
-func (n *Notifier) wakeupUser(userID string, newPos types.StreamPosition) {
+func (n *Notifier) wakeupUsers(userIDs []string, newPos types.SyncPosition) {
-	stream := n.fetchUserStream(userID, false)
+	for _, userID := range userIDs {
-	if stream == nil {
+		stream := n.fetchUserStream(userID, false)
-		return
+		if stream != nil {
+			stream.Broadcast(newPos) // wake up all goroutines Wait()ing on this stream
+		}
 	}
-	stream.Broadcast(newPos) // wakeup all goroutines Wait()ing on this stream
 }
 
 // fetchUserStream retrieves a stream unique to the given user. If makeIfNotExists is true,

syncapi/sync/notifier_test.go

@@ -32,19 +32,40 @@ var (
 	randomMessageEvent  gomatrixserverlib.Event
 	aliceInviteBobEvent gomatrixserverlib.Event
 	bobLeaveEvent       gomatrixserverlib.Event
+	syncPositionVeryOld types.SyncPosition
+	syncPositionBefore  types.SyncPosition
+	syncPositionAfter   types.SyncPosition
+	syncPositionNewEDU  types.SyncPosition
+	syncPositionAfter2  types.SyncPosition
 )
 
 var (
-	streamPositionVeryOld = types.StreamPosition(5)
+	roomID = "!test:localhost"
-	streamPositionBefore  = types.StreamPosition(11)
+	alice  = "@alice:localhost"
-	streamPositionAfter   = types.StreamPosition(12)
+	bob    = "@bob:localhost"
-	streamPositionAfter2  = types.StreamPosition(13)
-	roomID                = "!test:localhost"
-	alice                 = "@alice:localhost"
-	bob                   = "@bob:localhost"
 )
 
 func init() {
+	baseSyncPos := types.SyncPosition{
+		PDUPosition:    0,
+		TypingPosition: 0,
+	}
+
+	syncPositionVeryOld = baseSyncPos
+	syncPositionVeryOld.PDUPosition = 5
+
+	syncPositionBefore = baseSyncPos
+	syncPositionBefore.PDUPosition = 11
+
+	syncPositionAfter = baseSyncPos
+	syncPositionAfter.PDUPosition = 12
+
+	syncPositionNewEDU = syncPositionAfter
+	syncPositionNewEDU.TypingPosition = 1
+
+	syncPositionAfter2 = baseSyncPos
+	syncPositionAfter2.PDUPosition = 13
+
 	var err error
 	randomMessageEvent, err = gomatrixserverlib.NewEventFromTrustedJSON([]byte(`{
 		"type": "m.room.message",
@@ -92,19 +113,19 @@ func init() {
 
 // Test that the current position is returned if a request is already behind.
 func TestImmediateNotification(t *testing.T) {
-	n := NewNotifier(streamPositionBefore)
+	n := NewNotifier(syncPositionBefore)
-	pos, err := waitForEvents(n, newTestSyncRequest(alice, streamPositionVeryOld))
+	pos, err := waitForEvents(n, newTestSyncRequest(alice, syncPositionVeryOld))
 	if err != nil {
 		t.Fatalf("TestImmediateNotification error: %s", err)
 	}
-	if pos != streamPositionBefore {
+	if pos != syncPositionBefore {
-		t.Fatalf("TestImmediateNotification want %d, got %d", streamPositionBefore, pos)
+		t.Fatalf("TestImmediateNotification want %d, got %d", syncPositionBefore, pos)
 	}
 }
 
 // Test that new events to a joined room unblocks the request.
 func TestNewEventAndJoinedToRoom(t *testing.T) {
-	n := NewNotifier(streamPositionBefore)
+	n := NewNotifier(syncPositionBefore)
 	n.setUsersJoinedToRooms(map[string][]string{
 		roomID: {alice, bob},
 	})
@@ -112,12 +133,12 @@ func TestNewEventAndJoinedToRoom(t *testing.T) {
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
-		pos, err := waitForEvents(n, newTestSyncRequest(bob, streamPositionBefore))
+		pos, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionBefore))
 		if err != nil {
 			t.Errorf("TestNewEventAndJoinedToRoom error: %s", err)
 		}
-		if pos != streamPositionAfter {
+		if pos != syncPositionAfter {
-			t.Errorf("TestNewEventAndJoinedToRoom want %d, got %d", streamPositionAfter, pos)
+			t.Errorf("TestNewEventAndJoinedToRoom want %d, got %d", syncPositionAfter, pos)
 		}
 		wg.Done()
 	}()
@@ -125,14 +146,14 @@ func TestNewEventAndJoinedToRoom(t *testing.T) {
 	stream := n.fetchUserStream(bob, true)
 	waitForBlocking(stream, 1)
 
-	n.OnNewEvent(&randomMessageEvent, "", streamPositionAfter)
+	n.OnNewEvent(&randomMessageEvent, "", nil, syncPositionAfter)
 
 	wg.Wait()
 }
 
 // Test that an invite unblocks the request
 func TestNewInviteEventForUser(t *testing.T) {
-	n := NewNotifier(streamPositionBefore)
+	n := NewNotifier(syncPositionBefore)
 	n.setUsersJoinedToRooms(map[string][]string{
 		roomID: {alice, bob},
 	})
@@ -140,12 +161,12 @@ func TestNewInviteEventForUser(t *testing.T) {
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
-		pos, err := waitForEvents(n, newTestSyncRequest(bob, streamPositionBefore))
+		pos, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionBefore))
 		if err != nil {
 			t.Errorf("TestNewInviteEventForUser error: %s", err)
 		}
-		if pos != streamPositionAfter {
+		if pos != syncPositionAfter {
-			t.Errorf("TestNewInviteEventForUser want %d, got %d", streamPositionAfter, pos)
+			t.Errorf("TestNewInviteEventForUser want %d, got %d", syncPositionAfter, pos)
 		}
 		wg.Done()
 	}()
@@ -153,14 +174,42 @@ func TestNewInviteEventForUser(t *testing.T) {
 	stream := n.fetchUserStream(bob, true)
 	waitForBlocking(stream, 1)
 
-	n.OnNewEvent(&aliceInviteBobEvent, "", streamPositionAfter)
+	n.OnNewEvent(&aliceInviteBobEvent, "", nil, syncPositionAfter)
+
+	wg.Wait()
+}
+
+// Test an EDU-only update wakes up the request.
+func TestEDUWakeup(t *testing.T) {
+	n := NewNotifier(syncPositionAfter)
+	n.setUsersJoinedToRooms(map[string][]string{
+		roomID: {alice, bob},
+	})
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		pos, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionAfter))
+		if err != nil {
+			t.Errorf("TestNewInviteEventForUser error: %s", err)
+		}
+		if pos != syncPositionNewEDU {
+			t.Errorf("TestNewInviteEventForUser want %d, got %d", syncPositionNewEDU, pos)
+		}
+		wg.Done()
+	}()
+
+	stream := n.fetchUserStream(bob, true)
+	waitForBlocking(stream, 1)
+
+	n.OnNewEvent(&aliceInviteBobEvent, "", nil, syncPositionNewEDU)
 
 	wg.Wait()
 }
 
 // Test that all blocked requests get woken up on a new event.
 func TestMultipleRequestWakeup(t *testing.T) {
-	n := NewNotifier(streamPositionBefore)
+	n := NewNotifier(syncPositionBefore)
 	n.setUsersJoinedToRooms(map[string][]string{
 		roomID: {alice, bob},
 	})
@@ -168,12 +217,12 @@ func TestMultipleRequestWakeup(t *testing.T) {
 	var wg sync.WaitGroup
 	wg.Add(3)
 	poll := func() {
-		pos, err := waitForEvents(n, newTestSyncRequest(bob, streamPositionBefore))
+		pos, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionBefore))
 		if err != nil {
 			t.Errorf("TestMultipleRequestWakeup error: %s", err)
 		}
-		if pos != streamPositionAfter {
+		if pos != syncPositionAfter {
-			t.Errorf("TestMultipleRequestWakeup want %d, got %d", streamPositionAfter, pos)
+			t.Errorf("TestMultipleRequestWakeup want %d, got %d", syncPositionAfter, pos)
 		}
 		wg.Done()
 	}
@@ -184,7 +233,7 @@ func TestMultipleRequestWakeup(t *testing.T) {
 	stream := n.fetchUserStream(bob, true)
 	waitForBlocking(stream, 3)
 
-	n.OnNewEvent(&randomMessageEvent, "", streamPositionAfter)
+	n.OnNewEvent(&randomMessageEvent, "", nil, syncPositionAfter)
 
 	wg.Wait()
 
@@ -198,7 +247,7 @@ func TestMultipleRequestWakeup(t *testing.T) {
 func TestNewEventAndWasPreviouslyJoinedToRoom(t *testing.T) {
 	// listen as bob. Make bob leave room. Make alice send event to room.
 	// Make sure alice gets woken up only and not bob as well.
-	n := NewNotifier(streamPositionBefore)
+	n := NewNotifier(syncPositionBefore)
 	n.setUsersJoinedToRooms(map[string][]string{
 		roomID: {alice, bob},
 	})
@@ -208,18 +257,18 @@ func TestNewEventAndWasPreviouslyJoinedToRoom(t *testing.T) {
 	// Make bob leave the room
 	leaveWG.Add(1)
 	go func() {
-		pos, err := waitForEvents(n, newTestSyncRequest(bob, streamPositionBefore))
+		pos, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionBefore))
 		if err != nil {
 			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom error: %s", err)
 		}
-		if pos != streamPositionAfter {
+		if pos != syncPositionAfter {
-			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom want %d, got %d", streamPositionAfter, pos)
+			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom want %d, got %d", syncPositionAfter, pos)
 		}
 		leaveWG.Done()
 	}()
 	bobStream := n.fetchUserStream(bob, true)
 	waitForBlocking(bobStream, 1)
-	n.OnNewEvent(&bobLeaveEvent, "", streamPositionAfter)
+	n.OnNewEvent(&bobLeaveEvent, "", nil, syncPositionAfter)
 	leaveWG.Wait()
 
 	// send an event into the room. Make sure alice gets it. Bob should not.
@@ -227,19 +276,19 @@ func TestNewEventAndWasPreviouslyJoinedToRoom(t *testing.T) {
 	aliceStream := n.fetchUserStream(alice, true)
 	aliceWG.Add(1)
 	go func() {
-		pos, err := waitForEvents(n, newTestSyncRequest(alice, streamPositionAfter))
+		pos, err := waitForEvents(n, newTestSyncRequest(alice, syncPositionAfter))
 		if err != nil {
 			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom error: %s", err)
 		}
-		if pos != streamPositionAfter2 {
+		if pos != syncPositionAfter2 {
-			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom want %d, got %d", streamPositionAfter2, pos)
+			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom want %d, got %d", syncPositionAfter2, pos)
 		}
 		aliceWG.Done()
 	}()
 
 	go func() {
 		// this should timeout with an error (but the main goroutine won't wait for the timeout explicitly)
-		_, err := waitForEvents(n, newTestSyncRequest(bob, streamPositionAfter))
+		_, err := waitForEvents(n, newTestSyncRequest(bob, syncPositionAfter))
 		if err == nil {
 			t.Errorf("TestNewEventAndWasPreviouslyJoinedToRoom expect error but got nil")
 		}
@@ -248,7 +297,7 @@ func TestNewEventAndWasPreviouslyJoinedToRoom(t *testing.T) {
 	waitForBlocking(aliceStream, 1)
 	waitForBlocking(bobStream, 1)
 
-	n.OnNewEvent(&randomMessageEvent, "", streamPositionAfter2)
+	n.OnNewEvent(&randomMessageEvent, "", nil, syncPositionAfter2)
 	aliceWG.Wait()
 
 	// it's possible that at this point alice has been informed and bob is about to be informed, so wait
@@ -256,18 +305,17 @@ func TestNewEventAndWasPreviouslyJoinedToRoom(t *testing.T) {
 	time.Sleep(1 * time.Millisecond)
 }
 
-// same as Notifier.WaitForEvents but with a timeout.
+func waitForEvents(n *Notifier, req syncRequest) (types.SyncPosition, error) {
-func waitForEvents(n *Notifier, req syncRequest) (types.StreamPosition, error) {
 	listener := n.GetListener(req)
 	defer listener.Close()
 
 	select {
 	case <-time.After(5 * time.Second):
-		return types.StreamPosition(0), fmt.Errorf(
+		return types.SyncPosition{}, fmt.Errorf(
 			"waitForEvents timed out waiting for %s (pos=%d)", req.device.UserID, req.since,
 		)
 	case <-listener.GetNotifyChannel(*req.since):
-		p := listener.GetStreamPosition()
+		p := listener.GetSyncPosition()
 		return p, nil
 	}
 }
@@ -280,7 +328,7 @@ func waitForBlocking(s *UserStream, numBlocking uint) {
 	}
 }
 
-func newTestSyncRequest(userID string, since types.StreamPosition) syncRequest {
+func newTestSyncRequest(userID string, since types.SyncPosition) syncRequest {
 	return syncRequest{
 		device:        authtypes.Device{UserID: userID},
 		timeout:       1 * time.Minute,

syncapi/sync/request.go

@@ -16,8 +16,10 @@ package sync
 
 import (
 	"context"
+	"errors"
 	"net/http"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
@@ -36,7 +38,7 @@ type syncRequest struct {
 	device        authtypes.Device
 	limit         int
 	timeout       time.Duration
-	since         *types.StreamPosition // nil means that no since token was supplied
+	since         *types.SyncPosition // nil means that no since token was supplied
 	wantFullState bool
 	log           *log.Entry
 }
@@ -73,15 +75,41 @@ func getTimeout(timeoutMS string) time.Duration {
 }
 
 // getSyncStreamPosition tries to parse a 'since' token taken from the API to a
-// stream position. If the string is empty then (nil, nil) is returned.
+// types.SyncPosition. If the string is empty then (nil, nil) is returned.
-func getSyncStreamPosition(since string) (*types.StreamPosition, error) {
+// There are two forms of tokens: The full length form containing all PDU and EDU
+// positions separated by "_", and the short form containing only the PDU
+// position. Short form can be used for, e.g., `prev_batch` tokens.
+func getSyncStreamPosition(since string) (*types.SyncPosition, error) {
 	if since == "" {
 		return nil, nil
 	}
-	i, err := strconv.Atoi(since)
+
-	if err != nil {
+	posStrings := strings.Split(since, "_")
-		return nil, err
+	if len(posStrings) != 2 && len(posStrings) != 1 {
+		// A token can either be full length or short (PDU-only).
+		return nil, errors.New("malformed batch token")
+	}
+
+	positions := make([]int64, len(posStrings))
+	for i, posString := range posStrings {
+		pos, err := strconv.ParseInt(posString, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		positions[i] = pos
+	}
+
+	if len(positions) == 2 {
+		// Full length token; construct SyncPosition with every entry in
+		// `positions`. These entries must have the same order with the fields
+		// in struct SyncPosition, so we disable the govet check below.
+		return &types.SyncPosition{ //nolint:govet
+			positions[0], positions[1],
+		}, nil
+	} else {
+		// Token with PDU position only
+		return &types.SyncPosition{
+			PDUPosition: positions[0],
+		}, nil
 	}
-	token := types.StreamPosition(i)
-	return &token, nil
 }

syncapi/sync/requestpool.go

@@ -31,13 +31,13 @@ import (
 
 // RequestPool manages HTTP long-poll connections for /sync
 type RequestPool struct {
-	db        *storage.SyncServerDatabase
+	db        *storage.SyncServerDatasource
 	accountDB *accounts.Database
 	notifier  *Notifier
 }
 
 // NewRequestPool makes a new RequestPool
-func NewRequestPool(db *storage.SyncServerDatabase, n *Notifier, adb *accounts.Database) *RequestPool {
+func NewRequestPool(db *storage.SyncServerDatasource, n *Notifier, adb *accounts.Database) *RequestPool {
 	return &RequestPool{db, adb, n}
 }
 
@@ -92,11 +92,13 @@ func (rp *RequestPool) OnIncomingSyncRequest(req *http.Request, device *authtype
 	// respond with, so we skip the return an go back to waiting for content to
 	// be sent down or the request timing out.
 	var hasTimedOut bool
+	sincePos := *syncReq.since
 	for {
 		select {
 		// Wait for notifier to wake us up
-		case <-userStreamListener.GetNotifyChannel(currPos):
+		case <-userStreamListener.GetNotifyChannel(sincePos):
-			currPos = userStreamListener.GetStreamPosition()
+			currPos = userStreamListener.GetSyncPosition()
+			sincePos = currPos
 		// Or for timeout to expire
 		case <-timer.C:
 			// We just need to ensure we get out of the select after reaching the
@@ -128,24 +130,24 @@ func (rp *RequestPool) OnIncomingSyncRequest(req *http.Request, device *authtype
 	}
 }
 
-func (rp *RequestPool) currentSyncForUser(req syncRequest, currentPos types.StreamPosition) (res *types.Response, err error) {
+func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.SyncPosition) (res *types.Response, err error) {
 	// TODO: handle ignored users
 	if req.since == nil {
 		res, err = rp.db.CompleteSync(req.ctx, req.device.UserID, req.limit)
 	} else {
-		res, err = rp.db.IncrementalSync(req.ctx, req.device, *req.since, currentPos, req.limit)
+		res, err = rp.db.IncrementalSync(req.ctx, req.device, *req.since, latestPos, req.limit)
 	}
 
 	if err != nil {
 		return
 	}
 
-	res, err = rp.appendAccountData(res, req.device.UserID, req, currentPos)
+	res, err = rp.appendAccountData(res, req.device.UserID, req, latestPos.PDUPosition)
 	return
 }
 
 func (rp *RequestPool) appendAccountData(
-	data *types.Response, userID string, req syncRequest, currentPos types.StreamPosition,
+	data *types.Response, userID string, req syncRequest, currentPos int64,
 ) (*types.Response, error) {
 	// TODO: Account data doesn't have a sync position of its own, meaning that
 	// account data might be sent multiple time to the client if multiple account
@@ -179,7 +181,7 @@ func (rp *RequestPool) appendAccountData(
 	}
 
 	// Sync is not initial, get all account data since the latest sync
-	dataTypes, err := rp.db.GetAccountDataInRange(req.ctx, userID, *req.since, currentPos)
+	dataTypes, err := rp.db.GetAccountDataInRange(req.ctx, userID, req.since.PDUPosition, currentPos)
 	if err != nil {
 		return nil, err
 	}

syncapi/sync/userstream.go

@@ -34,8 +34,8 @@ type UserStream struct {
 	lock sync.Mutex
 	// Closed when there is an update.
 	signalChannel chan struct{}
-	// The last stream position that there may have been an update for the suser
+	// The last sync position that there may have been an update for the user
-	pos types.StreamPosition
+	pos types.SyncPosition
 	// The last time when we had some listeners waiting
 	timeOfLastChannel time.Time
 	// The number of listeners waiting
@@ -51,7 +51,7 @@ type UserStreamListener struct {
 }
 
 // NewUserStream creates a new user stream
-func NewUserStream(userID string, currPos types.StreamPosition) *UserStream {
+func NewUserStream(userID string, currPos types.SyncPosition) *UserStream {
 	return &UserStream{
 		UserID:            userID,
 		timeOfLastChannel: time.Now(),
@@ -84,8 +84,8 @@ func (s *UserStream) GetListener(ctx context.Context) UserStreamListener {
 	return listener
 }
 
-// Broadcast a new stream position for this user.
+// Broadcast a new sync position for this user.
-func (s *UserStream) Broadcast(pos types.StreamPosition) {
+func (s *UserStream) Broadcast(pos types.SyncPosition) {
 	s.lock.Lock()
 	defer s.lock.Unlock()
 
@@ -118,9 +118,9 @@ func (s *UserStream) TimeOfLastNonEmpty() time.Time {
 	return s.timeOfLastChannel
 }
 
-// GetStreamPosition returns last stream position which the UserStream was
+// GetStreamPosition returns last sync position which the UserStream was
 // notified about
-func (s *UserStreamListener) GetStreamPosition() types.StreamPosition {
+func (s *UserStreamListener) GetSyncPosition() types.SyncPosition {
 	s.userStream.lock.Lock()
 	defer s.userStream.lock.Unlock()
 
@@ -132,11 +132,11 @@ func (s *UserStreamListener) GetStreamPosition() types.StreamPosition {
 // sincePos specifies from which point we want to be notified about. If there
 // has already been an update after sincePos we'll return a closed channel
 // immediately.
-func (s *UserStreamListener) GetNotifyChannel(sincePos types.StreamPosition) <-chan struct{} {
+func (s *UserStreamListener) GetNotifyChannel(sincePos types.SyncPosition) <-chan struct{} {
 	s.userStream.lock.Lock()
 	defer s.userStream.lock.Unlock()
 
-	if sincePos < s.userStream.pos {
+	if s.userStream.pos.IsAfter(sincePos) {
 		// If the listener is behind, i.e. missed a potential update, then we
 		// want them to wake up immediately. We do this by returning a new
 		// closed stream, which returns immediately when selected.

syncapi/syncapi.go

@@ -28,7 +28,6 @@ import (
 	"github.com/matrix-org/dendrite/syncapi/routing"
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/sync"
-	"github.com/matrix-org/dendrite/syncapi/types"
 )
 
 // SetupSyncAPIComponent sets up and registers HTTP handlers for the SyncAPI
@@ -39,17 +38,17 @@ func SetupSyncAPIComponent(
 	accountsDB *accounts.Database,
 	queryAPI api.RoomserverQueryAPI,
 ) {
-	syncDB, err := storage.NewSyncServerDatabase(string(base.Cfg.Database.SyncAPI))
+	syncDB, err := storage.NewSyncServerDatasource(string(base.Cfg.Database.SyncAPI))
 	if err != nil {
 		logrus.WithError(err).Panicf("failed to connect to sync db")
 	}
 
-	pos, err := syncDB.SyncStreamPosition(context.Background())
+	pos, err := syncDB.SyncPosition(context.Background())
 	if err != nil {
-		logrus.WithError(err).Panicf("failed to get stream position")
+		logrus.WithError(err).Panicf("failed to get sync position")
 	}
 
-	notifier := sync.NewNotifier(types.StreamPosition(pos))
+	notifier := sync.NewNotifier(pos)
 	err = notifier.Load(context.Background(), syncDB)
 	if err != nil {
 		logrus.WithError(err).Panicf("failed to start notifier")
@@ -71,5 +70,12 @@ func SetupSyncAPIComponent(
 		logrus.WithError(err).Panicf("failed to start client data consumer")
 	}
 
+	typingConsumer := consumers.NewOutputTypingEventConsumer(
+		base.Cfg, base.KafkaConsumer, notifier, syncDB,
+	)
+	if err = typingConsumer.Start(); err != nil {
+		logrus.WithError(err).Panicf("failed to start typing server consumer")
+	}
+
 	routing.Setup(base.APIMux, requestPool, syncDB, deviceDB)
 }

syncapi/types/types.go

@@ -21,12 +21,38 @@ import (
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
-// StreamPosition represents the offset in the sync stream a client is at.
+// SyncPosition contains the PDU and EDU stream sync positions for a client.
-type StreamPosition int64
+type SyncPosition struct {
+	// PDUPosition is the stream position for PDUs the client is at.
+	PDUPosition int64
+	// TypingPosition is the client's position for typing notifications.
+	TypingPosition int64
+}
 
 // String implements the Stringer interface.
-func (sp StreamPosition) String() string {
+func (sp SyncPosition) String() string {
-	return strconv.FormatInt(int64(sp), 10)
+	return strconv.FormatInt(sp.PDUPosition, 10) + "_" +
+		strconv.FormatInt(sp.TypingPosition, 10)
+}
+
+// IsAfter returns whether one SyncPosition refers to states newer than another SyncPosition.
+func (sp SyncPosition) IsAfter(other SyncPosition) bool {
+	return sp.PDUPosition > other.PDUPosition ||
+		sp.TypingPosition > other.TypingPosition
+}
+
+// WithUpdates returns a copy of the SyncPosition with updates applied from another SyncPosition.
+// If the latter SyncPosition contains a field that is not 0, it is considered an update,
+// and its value will replace the corresponding value in the SyncPosition on which WithUpdates is called.
+func (sp SyncPosition) WithUpdates(other SyncPosition) SyncPosition {
+	ret := sp
+	if other.PDUPosition != 0 {
+		ret.PDUPosition = other.PDUPosition
+	}
+	if other.TypingPosition != 0 {
+		ret.TypingPosition = other.TypingPosition
+	}
+	return ret
 }
 
 // PrevEventRef represents a reference to a previous event in a state event upgrade
@@ -53,11 +79,10 @@ type Response struct {
 }
 
 // NewResponse creates an empty response with initialised maps.
-func NewResponse(pos StreamPosition) *Response {
+func NewResponse(pos SyncPosition) *Response {
-	res := Response{}
+	res := Response{
-	// Make sure we send the next_batch as a string. We don't want to confuse clients by sending this
+		NextBatch: pos.String(),
-	// as an integer even though (at the moment) it is.
+	}
-	res.NextBatch = pos.String()
 	// Pre-initialise the maps. Synapse will return {} even if there are no rooms under a specific section,
 	// so let's do the same thing. Bonus: this means we can't get dreaded 'assignment to entry in nil map' errors.
 	res.Rooms.Join = make(map[string]JoinResponse)

testfile

@@ -144,3 +144,6 @@ Events come down the correct room
 local user can join room with version 5
 User can invite local user to room with version 5
 Inbound federation can receive room-join requests
+Typing events appear in initial sync
+Typing events appear in incremental sync
+Typing events appear in gapped sync

typingserver/api/output.go

@@ -12,14 +12,17 @@
 
 package api
 
+import "time"
+
 // OutputTypingEvent is an entry in typing server output kafka log.
 // This contains the event with extra fields used to create 'm.typing' event
 // in clientapi & federation.
 type OutputTypingEvent struct {
 	// The Event for the typing edu event.
 	Event TypingEvent `json:"event"`
-	// Users typing in the room when the event was generated.
+	// ExpireTime is the interval after which the user should no longer be
-	TypingUsers []string `json:"typing_users"`
+	// considered typing. Only available if Event.Typing is true.
+	ExpireTime *time.Time
 }
 
 // TypingEvent represents a matrix edu event of type 'm.typing'.

typingserver/cache/cache.go

@@ -22,25 +22,66 @@ const defaultTypingTimeout = 10 * time.Second
 // userSet is a map of user IDs to a timer, timer fires at expiry.
 type userSet map[string]*time.Timer
 
+// TimeoutCallbackFn is a function called right after the removal of a user
+// from the typing user list due to timeout.
+// latestSyncPosition is the typing sync position after the removal.
+type TimeoutCallbackFn func(userID, roomID string, latestSyncPosition int64)
+
+type roomData struct {
+	syncPosition int64
+	userSet      userSet
+}
+
 // TypingCache maintains a list of users typing in each room.
 type TypingCache struct {
 	sync.RWMutex
-	data map[string]userSet
+	latestSyncPosition int64
+	data               map[string]*roomData
+	timeoutCallback    TimeoutCallbackFn
+}
+
+// Create a roomData with its sync position set to the latest sync position.
+// Must only be called after locking the cache.
+func (t *TypingCache) newRoomData() *roomData {
+	return &roomData{
+		syncPosition: t.latestSyncPosition,
+		userSet:      make(userSet),
+	}
 }
 
 // NewTypingCache returns a new TypingCache initialised for use.
 func NewTypingCache() *TypingCache {
-	return &TypingCache{data: make(map[string]userSet)}
+	return &TypingCache{data: make(map[string]*roomData)}
+}
+
+// SetTimeoutCallback sets a callback function that is called right after
+// a user is removed from the typing user list due to timeout.
+func (t *TypingCache) SetTimeoutCallback(fn TimeoutCallbackFn) {
+	t.timeoutCallback = fn
 }
 
 // GetTypingUsers returns the list of users typing in a room.
-func (t *TypingCache) GetTypingUsers(roomID string) (users []string) {
+func (t *TypingCache) GetTypingUsers(roomID string) []string {
+	users, _ := t.GetTypingUsersIfUpdatedAfter(roomID, 0)
+	// 0 should work above because the first position used will be 1.
+	return users
+}
+
+// GetTypingUsersIfUpdatedAfter returns all users typing in this room with
+// updated == true if the typing sync position of the room is after the given
+// position. Otherwise, returns an empty slice with updated == false.
+func (t *TypingCache) GetTypingUsersIfUpdatedAfter(
+	roomID string, position int64,
+) (users []string, updated bool) {
 	t.RLock()
-	usersMap, ok := t.data[roomID]
+	defer t.RUnlock()
-	t.RUnlock()
+
-	if ok {
+	roomData, ok := t.data[roomID]
-		users = make([]string, 0, len(usersMap))
+	if ok && roomData.syncPosition > position {
-		for userID := range usersMap {
+		updated = true
+		userSet := roomData.userSet
+		users = make([]string, 0, len(userSet))
+		for userID := range userSet {
 			users = append(users, userID)
 		}
 	}
@@ -51,25 +92,41 @@ func (t *TypingCache) GetTypingUsers(roomID string) (users []string) {
 // AddTypingUser sets an user as typing in a room.
 // expire is the time when the user typing should time out.
 // if expire is nil, defaultTypingTimeout is assumed.
-func (t *TypingCache) AddTypingUser(userID, roomID string, expire *time.Time) {
+// Returns the latest sync position for typing after update.
+func (t *TypingCache) AddTypingUser(
+	userID, roomID string, expire *time.Time,
+) int64 {
 	expireTime := getExpireTime(expire)
 	if until := time.Until(expireTime); until > 0 {
-		timer := time.AfterFunc(until, t.timeoutCallback(userID, roomID))
+		timer := time.AfterFunc(until, func() {
-		t.addUser(userID, roomID, timer)
+			latestSyncPosition := t.RemoveUser(userID, roomID)
+			if t.timeoutCallback != nil {
+				t.timeoutCallback(userID, roomID, latestSyncPosition)
+			}
+		})
+		return t.addUser(userID, roomID, timer)
 	}
+	return t.GetLatestSyncPosition()
 }
 
 // addUser with mutex lock & replace the previous timer.
-func (t *TypingCache) addUser(userID, roomID string, expiryTimer *time.Timer) {
+// Returns the latest typing sync position after update.
+func (t *TypingCache) addUser(
+	userID, roomID string, expiryTimer *time.Timer,
+) int64 {
 	t.Lock()
 	defer t.Unlock()
 
+	t.latestSyncPosition++
+
 	if t.data[roomID] == nil {
-		t.data[roomID] = make(userSet)
+		t.data[roomID] = t.newRoomData()
+	} else {
+		t.data[roomID].syncPosition = t.latestSyncPosition
 	}
 
 	// Stop the timer to cancel the call to timeoutCallback
-	if timer, ok := t.data[roomID][userID]; ok {
+	if timer, ok := t.data[roomID].userSet[userID]; ok {
 		// It may happen that at this stage timer fires but now we have a lock on t.
 		// Hence the execution of timeoutCallback will happen after we unlock.
 		// So we may lose a typing state, though this event is highly unlikely.
@@ -78,26 +135,40 @@ func (t *TypingCache) addUser(userID, roomID string, expiryTimer *time.Timer) {
 		timer.Stop()
 	}
 
-	t.data[roomID][userID] = expiryTimer
+	t.data[roomID].userSet[userID] = expiryTimer
-}
 
-// Returns a function which is called after timeout happens.
+	return t.latestSyncPosition
-// This removes the user.
-func (t *TypingCache) timeoutCallback(userID, roomID string) func() {
-	return func() {
-		t.RemoveUser(userID, roomID)
-	}
 }
 
 // RemoveUser with mutex lock & stop the timer.
-func (t *TypingCache) RemoveUser(userID, roomID string) {
+// Returns the latest sync position for typing after update.
+func (t *TypingCache) RemoveUser(userID, roomID string) int64 {
 	t.Lock()
 	defer t.Unlock()
 
-	if timer, ok := t.data[roomID][userID]; ok {
+	roomData, ok := t.data[roomID]
-		timer.Stop()
+	if !ok {
-		delete(t.data[roomID], userID)
+		return t.latestSyncPosition
 	}
+
+	timer, ok := roomData.userSet[userID]
+	if !ok {
+		return t.latestSyncPosition
+	}
+
+	timer.Stop()
+	delete(roomData.userSet, userID)
+
+	t.latestSyncPosition++
+	t.data[roomID].syncPosition = t.latestSyncPosition
+
+	return t.latestSyncPosition
+}
+
+func (t *TypingCache) GetLatestSyncPosition() int64 {
+	t.Lock()
+	defer t.Unlock()
+	return t.latestSyncPosition
 }
 
 func getExpireTime(expire *time.Time) time.Time {

typingserver/input/input.go

@@ -57,15 +57,21 @@ func (t *TypingServerInputAPI) InputTypingEvent(
 }
 
 func (t *TypingServerInputAPI) sendEvent(ite *api.InputTypingEvent) error {
-	userIDs := t.Cache.GetTypingUsers(ite.RoomID)
 	ev := &api.TypingEvent{
 		Type:   gomatrixserverlib.MTyping,
 		RoomID: ite.RoomID,
 		UserID: ite.UserID,
+		Typing: ite.Typing,
 	}
 	ote := &api.OutputTypingEvent{
-		Event:       *ev,
+		Event: *ev,
-		TypingUsers: userIDs,
+	}
+
+	if ev.Typing {
+		expireTime := ite.OriginServerTS.Time().Add(
+			time.Duration(ite.Timeout) * time.Millisecond,
+		)
+		ote.ExpireTime = &expireTime
 	}
 
 	eventJSON, err := json.Marshal(ote)