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/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
+}