Fulltext implementation using Bleve (#2675)

Based on #2480

This actually indexes events based on their event type. They are removed
from the index if we receive a `m.room.redaction` event on the
`OutputRoomEvent` stream.
An admin endpoint is added to reindex all existing events.


Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

clientapi/routing/admin.go

@@ -3,15 +3,19 @@ package routing
 import (
 	"encoding/json"
 	"net/http"
+	"time"
 
 	"github.com/gorilla/mux"
 	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	"github.com/matrix-org/dendrite/internal/httputil"
 	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/setup/jetstream"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
+	"github.com/nats-io/nats.go"
+	"github.com/sirupsen/logrus"
 )
 
 func AdminEvacuateRoom(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, rsAPI roomserverAPI.ClientRoomserverAPI) util.JSONResponse {
@@ -138,3 +142,21 @@ func AdminResetPassword(req *http.Request, cfg *config.ClientAPI, device *userap
 		},
 	}
 }
+
+func AdminReindex(req *http.Request, cfg *config.ClientAPI, device *userapi.Device, natsClient *nats.Conn) util.JSONResponse {
+	if device.AccountType != userapi.AccountTypeAdmin {
+		return util.JSONResponse{
+			Code: http.StatusForbidden,
+			JSON: jsonerror.Forbidden("This API can only be used by admin users."),
+		}
+	}
+	_, err := natsClient.RequestMsg(nats.NewMsg(cfg.Matrix.JetStream.Prefixed(jetstream.InputFulltextReindex)), time.Second*10)
+	if err != nil {
+		logrus.WithError(err).Error("failed to publish nats message")
+		return jsonerror.InternalServerError()
+	}
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: struct{}{},
+	}
+}

clientapi/routing/routing.go

@@ -20,6 +20,12 @@ import (
 	"strings"
 
 	"github.com/gorilla/mux"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	"github.com/nats-io/nats.go"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/sirupsen/logrus"
+
 	appserviceAPI "github.com/matrix-org/dendrite/appservice/api"
 	"github.com/matrix-org/dendrite/clientapi/api"
 	"github.com/matrix-org/dendrite/clientapi/auth"
@@ -34,11 +40,6 @@ import (
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/jetstream"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
-	"github.com/matrix-org/gomatrixserverlib"
-	"github.com/matrix-org/util"
-	"github.com/nats-io/nats.go"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/sirupsen/logrus"
 )
 
 // Setup registers HTTP handlers with the given ServeMux. It also supplies the given http.Client
@@ -161,6 +162,12 @@ func Setup(
 		}),
 	).Methods(http.MethodPost, http.MethodOptions)
 
+	dendriteAdminRouter.Handle("/admin/fulltext/reindex",
+		httputil.MakeAuthAPI("admin_fultext_reindex", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			return AdminReindex(req, cfg, device, natsClient)
+		}),
+	).Methods(http.MethodGet, http.MethodOptions)
+
 	// server notifications
 	if cfg.Matrix.ServerNotices.Enabled {
 		logrus.Info("Enabling server notices at /_synapse/admin/v1/send_server_notice")

cmd/generate-config/main.go

@@ -5,10 +5,11 @@ import (
 	"fmt"
 	"path/filepath"
 
-	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/gomatrixserverlib"
 	"golang.org/x/crypto/bcrypt"
 	"gopkg.in/yaml.v2"
+
+	"github.com/matrix-org/dendrite/setup/config"
 )
 
 func main() {
@@ -82,6 +83,12 @@ func main() {
 				EnableInbound:  true,
 				EnableOutbound: true,
 			}
+			cfg.SyncAPI.Fulltext = config.Fulltext{
+				Enabled:   true,
+				IndexPath: config.Path(filepath.Join(*dirPath, "fulltextindex")),
+				InMemory:  true,
+				Language:  "en",
+			}
 		}
 	} else {
 		var err error

dendrite-sample.monolith.yaml

@@ -275,10 +275,15 @@ sync_api:
   # address of the client. This is likely required if Dendrite is running behind
   # a reverse proxy server.
   # real_ip_header: X-Real-IP
-  fulltext:
+
+  # Configuration for the fulltext search
+  search:
     enabled: false
+    # The path where the fulltext index will be created in.
     index_path: "./fulltextindex"
-    language: "en" # more possible languages can be found at https://github.com/blevesearch/bleve/tree/master/analysis/lang
+    # The language most likely to be used on the server - used when indexing, to ensure the returned results match the expectations.
+    # A full list of possible languages can be found at https://github.com/blevesearch/bleve/tree/master/analysis/lang
+    language: "en"
 
 # Configuration for the User API.
 user_api:

dendrite-sample.polylith.yaml

@@ -326,10 +326,15 @@ sync_api:
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
-  fulltext:
+
+  # Configuration for the fulltext search
+  search:
     enabled: false
+    # The path where the fulltext index will be created in.
     index_path: "./fulltextindex"
-    language: "en" # more possible languages can be found at https://github.com/blevesearch/bleve/tree/master/analysis/lang
+    # The language most likely to be used on the server - used when indexing, to ensure the returned results match the expectations.
+    # A full list of possible languages can be found at https://github.com/blevesearch/bleve/tree/master/analysis/lang
+    language: "en"
 
   # This option controls which HTTP header to inspect to find the real remote IP
   # address of the client. This is likely required if Dendrite is running behind

docs/administration/4_adminapi.md

@@ -57,6 +57,11 @@ Request body format:
 Reset the password of a local user. The `localpart` is the username only, i.e. if
 the full user ID is `@alice:domain.com` then the local part is `alice`.
 
+## GET `/_dendrite/admin/fulltext/reindex`
+
+This endpoint instructs Dendrite to reindex all searchable events (`m.room.message`, `m.room.topic` and `m.room.name`). An empty JSON body will be returned immediately.
+Indexing is done in the background, the server logs every 1000 events (or below) when they are being indexed. Once reindexing is done, you'll see something along the lines `Indexed 69586 events in 53.68223182s` in your debug logs.
+
 ## POST `/_synapse/admin/v1/send_server_notice`
 
 Request body format:

docs/installation/7_configuration.md

@@ -140,12 +140,12 @@ room_server:
 
 ## Fulltext search
 
-Dendrite supports experimental fulltext indexing using [Bleve](https://github.com/blevesearch/bleve), it is configured in the `sync_api` section as follows. Depending on the language most likely to be used on the server, it might make sense to change the `language` used when indexing, to ensure the returned results match the expections. A full list of possible languages can be found [here](https://github.com/blevesearch/bleve/tree/master/analysis/lang).
+Dendrite supports experimental fulltext indexing using [Bleve](https://github.com/blevesearch/bleve), it is configured in the `sync_api` section as follows. Depending on the language most likely to be used on the server, it might make sense to change the `language` used when indexing, to ensure the returned results match the expectations. A full list of possible languages can be found [here](https://github.com/blevesearch/bleve/tree/master/analysis/lang).
 
 ```yaml
 sync_api:
   # ...
-  fulltext:
+  search:
     enabled: false
     index_path: "./fulltextindex"
     language: "en"

internal/fulltext/bleve.go

@@ -22,8 +22,9 @@ import (
 
 	"github.com/blevesearch/bleve/v2"
 	"github.com/blevesearch/bleve/v2/mapping"
-	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/gomatrixserverlib"
+
+	"github.com/matrix-org/dendrite/setup/config"
 )
 
 // Search contains all existing bleve.Index

internal/fulltext/bleve_test.go

@@ -27,11 +27,11 @@ import (
 
 func mustOpenIndex(t *testing.T, tempDir string) *fulltext.Search {
 	t.Helper()
-	cfg := config.Fulltext{}
+	cfg := config.Fulltext{
-	cfg.Defaults(config.DefaultOpts{
+		Enabled:  true,
-		Generate:   true,
+		InMemory: true,
-		Monolithic: true,
+		Language: "en",
-	})
+	}
 	if tempDir != "" {
 		cfg.IndexPath = config.Path(tempDir)
 		cfg.InMemory = false

setup/base/base.go

@@ -37,16 +37,13 @@ import (
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/h2c"
 
+	"github.com/matrix-org/dendrite/internal"
 	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/internal/fulltext"
 	"github.com/matrix-org/dendrite/internal/httputil"
 	"github.com/matrix-org/dendrite/internal/pushgateway"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 
-	"github.com/matrix-org/dendrite/internal"
-	"github.com/matrix-org/dendrite/setup/jetstream"
-	"github.com/matrix-org/dendrite/setup/process"
-
 	"github.com/gorilla/mux"
 	"github.com/kardianos/minwinsvc"
 
@@ -61,6 +58,8 @@ import (
 	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
 	rsinthttp "github.com/matrix-org/dendrite/roomserver/inthttp"
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/setup/jetstream"
+	"github.com/matrix-org/dendrite/setup/process"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 	userapiinthttp "github.com/matrix-org/dendrite/userapi/inthttp"
 )

setup/config/config_syncapi.go

@@ -10,7 +10,7 @@ type SyncAPI struct {
 
 	RealIPHeader string `yaml:"real_ip_header"`
 
-	Fulltext Fulltext `yaml:"fulltext"`
+	Fulltext Fulltext `yaml:"search"`
 }
 
 func (c *SyncAPI) Defaults(opts DefaultOpts) {
@@ -52,16 +52,12 @@ func (f *Fulltext) Defaults(opts DefaultOpts) {
 	f.Enabled = false
 	f.IndexPath = "./fulltextindex"
 	f.Language = "en"
-	if opts.Generate {
-		f.Enabled = true
-		f.InMemory = true
-	}
 }
 
 func (f *Fulltext) Verify(configErrs *ConfigErrors, isMonolith bool) {
 	if !f.Enabled {
 		return
 	}
-	checkNotEmpty(configErrs, "syncapi.fulltext.index_path", string(f.IndexPath))
+	checkNotEmpty(configErrs, "syncapi.search.index_path", string(f.IndexPath))
-	checkNotEmpty(configErrs, "syncapi.fulltext.language", f.Language)
+	checkNotEmpty(configErrs, "syncapi.search.language", f.Language)
 }

syncapi/consumers/clientapi.go

@@ -17,14 +17,18 @@ package consumers
 import (
 	"context"
 	"encoding/json"
+	"strings"
+	"time"
 
 	"github.com/getsentry/sentry-go"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
 	"github.com/sirupsen/logrus"
 	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
 
 	"github.com/matrix-org/dendrite/internal/eventutil"
+	"github.com/matrix-org/dendrite/internal/fulltext"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/jetstream"
 	"github.com/matrix-org/dendrite/setup/process"
@@ -35,14 +39,18 @@ import (
 
 // OutputClientDataConsumer consumes events that originated in the client API server.
 type OutputClientDataConsumer struct {
-	ctx        context.Context
+	ctx          context.Context
-	jetstream  nats.JetStreamContext
+	jetstream    nats.JetStreamContext
-	durable    string
+	nats         *nats.Conn
-	topic      string
+	durable      string
-	db         storage.Database
+	topic        string
-	stream     types.StreamProvider
+	topicReIndex string
-	notifier   *notifier.Notifier
+	db           storage.Database
-	serverName gomatrixserverlib.ServerName
+	stream       types.StreamProvider
+	notifier     *notifier.Notifier
+	serverName   gomatrixserverlib.ServerName
+	fts          *fulltext.Search
+	cfg          *config.SyncAPI
 }
 
 // NewOutputClientDataConsumer creates a new OutputClientData consumer. Call Start() to begin consuming from room servers.
@@ -50,24 +58,93 @@ func NewOutputClientDataConsumer(
 	process *process.ProcessContext,
 	cfg *config.SyncAPI,
 	js nats.JetStreamContext,
+	nats *nats.Conn,
 	store storage.Database,
 	notifier *notifier.Notifier,
 	stream types.StreamProvider,
+	fts *fulltext.Search,
 ) *OutputClientDataConsumer {
 	return &OutputClientDataConsumer{
-		ctx:        process.Context(),
+		ctx:          process.Context(),
-		jetstream:  js,
+		jetstream:    js,
-		topic:      cfg.Matrix.JetStream.Prefixed(jetstream.OutputClientData),
+		topic:        cfg.Matrix.JetStream.Prefixed(jetstream.OutputClientData),
-		durable:    cfg.Matrix.JetStream.Durable("SyncAPIAccountDataConsumer"),
+		topicReIndex: cfg.Matrix.JetStream.Prefixed(jetstream.InputFulltextReindex),
-		db:         store,
+		durable:      cfg.Matrix.JetStream.Durable("SyncAPIAccountDataConsumer"),
-		notifier:   notifier,
+		nats:         nats,
-		stream:     stream,
+		db:           store,
-		serverName: cfg.Matrix.ServerName,
+		notifier:     notifier,
+		stream:       stream,
+		serverName:   cfg.Matrix.ServerName,
+		fts:          fts,
+		cfg:          cfg,
 	}
 }
 
 // Start consuming from room servers
 func (s *OutputClientDataConsumer) Start() error {
+	_, err := s.nats.Subscribe(s.topicReIndex, func(msg *nats.Msg) {
+		if err := msg.Ack(); err != nil {
+			return
+		}
+		if !s.cfg.Fulltext.Enabled {
+			logrus.Warn("Fulltext indexing is disabled")
+			return
+		}
+		ctx := context.Background()
+		logrus.Debugf("Starting to index events")
+		var offset int
+		start := time.Now()
+		count := 0
+		var id int64 = 0
+		for {
+			evs, err := s.db.ReIndex(ctx, 1000, id)
+			if err != nil {
+				logrus.WithError(err).Errorf("unable to get events to index")
+				return
+			}
+			if len(evs) == 0 {
+				break
+			}
+			logrus.Debugf("Indexing %d events", len(evs))
+			elements := make([]fulltext.IndexElement, 0, len(evs))
+
+			for streamPos, ev := range evs {
+				id = streamPos
+				e := fulltext.IndexElement{
+					EventID:        ev.EventID(),
+					RoomID:         ev.RoomID(),
+					StreamPosition: streamPos,
+				}
+				e.SetContentType(ev.Type())
+
+				switch ev.Type() {
+				case "m.room.message":
+					e.Content = gjson.GetBytes(ev.Content(), "body").String()
+				case gomatrixserverlib.MRoomName:
+					e.Content = gjson.GetBytes(ev.Content(), "name").String()
+				case gomatrixserverlib.MRoomTopic:
+					e.Content = gjson.GetBytes(ev.Content(), "topic").String()
+				default:
+					continue
+				}
+
+				if strings.TrimSpace(e.Content) == "" {
+					continue
+				}
+				elements = append(elements, e)
+			}
+			if err = s.fts.Index(elements...); err != nil {
+				logrus.WithError(err).Error("unable to index events")
+				continue
+			}
+			offset += len(evs)
+			count += len(elements)
+		}
+		logrus.Debugf("Indexed %d events in %v", count, time.Since(start))
+	})
+	if err != nil {
+		return err
+	}
 	return jetstream.JetStreamConsumer(
 		s.ctx, s.jetstream, s.topic, s.durable, 1,
 		s.onMessage, nats.DeliverAll(), nats.ManualAck(),

syncapi/consumers/roomserver.go

@@ -24,7 +24,9 @@ import (
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/nats-io/nats.go"
 	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
 
+	"github.com/matrix-org/dendrite/internal/fulltext"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/jetstream"
@@ -46,6 +48,7 @@ type OutputRoomEventConsumer struct {
 	pduStream    types.StreamProvider
 	inviteStream types.StreamProvider
 	notifier     *notifier.Notifier
+	fts          *fulltext.Search
 }
 
 // NewOutputRoomEventConsumer creates a new OutputRoomEventConsumer. Call Start() to begin consuming from room servers.
@@ -58,6 +61,7 @@ func NewOutputRoomEventConsumer(
 	pduStream types.StreamProvider,
 	inviteStream types.StreamProvider,
 	rsAPI api.SyncRoomserverAPI,
+	fts *fulltext.Search,
 ) *OutputRoomEventConsumer {
 	return &OutputRoomEventConsumer{
 		ctx:          process.Context(),
@@ -70,6 +74,7 @@ func NewOutputRoomEventConsumer(
 		pduStream:    pduStream,
 		inviteStream: inviteStream,
 		rsAPI:        rsAPI,
+		fts:          fts,
 	}
 }
 
@@ -251,6 +256,12 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 		}).Panicf("roomserver output log: write new event failure")
 		return nil
 	}
+	if err = s.writeFTS(ev, pduPos); err != nil {
+		log.WithFields(log.Fields{
+			"event_id": ev.EventID(),
+			"type":     ev.Type(),
+		}).WithError(err).Warn("failed to index fulltext element")
+	}
 
 	if pduPos, err = s.notifyJoinedPeeks(ctx, ev, pduPos); err != nil {
 		log.WithError(err).Errorf("Failed to notifyJoinedPeeks for PDU pos %d", pduPos)
@@ -295,6 +306,13 @@ func (s *OutputRoomEventConsumer) onOldRoomEvent(
 		return nil
 	}
 
+	if err = s.writeFTS(ev, pduPos); err != nil {
+		log.WithFields(log.Fields{
+			"event_id": ev.EventID(),
+			"type":     ev.Type(),
+		}).WithError(err).Warn("failed to index fulltext element")
+	}
+
 	if pduPos, err = s.notifyJoinedPeeks(ctx, ev, pduPos); err != nil {
 		log.WithError(err).Errorf("Failed to notifyJoinedPeeks for PDU pos %d", pduPos)
 		return err
@@ -451,3 +469,39 @@ func (s *OutputRoomEventConsumer) updateStateEvent(event *gomatrixserverlib.Head
 	event.Event, err = event.SetUnsigned(prev)
 	return event, err
 }
+
+func (s *OutputRoomEventConsumer) writeFTS(ev *gomatrixserverlib.HeaderedEvent, pduPosition types.StreamPosition) error {
+	if !s.cfg.Fulltext.Enabled {
+		return nil
+	}
+	e := fulltext.IndexElement{
+		EventID:        ev.EventID(),
+		RoomID:         ev.RoomID(),
+		StreamPosition: int64(pduPosition),
+	}
+	e.SetContentType(ev.Type())
+
+	switch ev.Type() {
+	case "m.room.message":
+		e.Content = gjson.GetBytes(ev.Content(), "body").String()
+	case gomatrixserverlib.MRoomName:
+		e.Content = gjson.GetBytes(ev.Content(), "name").String()
+	case gomatrixserverlib.MRoomTopic:
+		e.Content = gjson.GetBytes(ev.Content(), "topic").String()
+	case gomatrixserverlib.MRoomRedaction:
+		log.Tracef("Redacting event: %s", ev.Redacts())
+		if err := s.fts.Delete(ev.Redacts()); err != nil {
+			return fmt.Errorf("failed to delete entry from fulltext index: %w", err)
+		}
+		return nil
+	default:
+		return nil
+	}
+	if e.Content != "" {
+		log.Tracef("Indexing element: %+v", e)
+		if err := s.fts.Index(e); err != nil {
+			return err
+		}
+	}
+	return nil
+}

syncapi/routing/context.go

@@ -37,11 +37,11 @@ import (
 
 type ContextRespsonse struct {
 	End          string                          `json:"end"`
-	Event        gomatrixserverlib.ClientEvent   `json:"event"`
+	Event        *gomatrixserverlib.ClientEvent  `json:"event,omitempty"`
 	EventsAfter  []gomatrixserverlib.ClientEvent `json:"events_after,omitempty"`
 	EventsBefore []gomatrixserverlib.ClientEvent `json:"events_before,omitempty"`
 	Start        string                          `json:"start"`
-	State        []gomatrixserverlib.ClientEvent `json:"state"`
+	State        []gomatrixserverlib.ClientEvent `json:"state,omitempty"`
 }
 
 func Context(
@@ -162,8 +162,9 @@ func Context(
 	eventsAfterClient := gomatrixserverlib.HeaderedToClientEvents(eventsAfterFiltered, gomatrixserverlib.FormatAll)
 	newState := applyLazyLoadMembers(device, filter, eventsAfterClient, eventsBeforeClient, state, lazyLoadCache)
 
+	ev := gomatrixserverlib.HeaderedToClientEvent(&requestedEvent, gomatrixserverlib.FormatAll)
 	response := ContextRespsonse{
-		Event:        gomatrixserverlib.HeaderedToClientEvent(&requestedEvent, gomatrixserverlib.FormatAll),
+		Event:        &ev,
 		EventsAfter:  eventsAfterClient,
 		EventsBefore: eventsBeforeClient,
 		State:        gomatrixserverlib.HeaderedToClientEvents(newState, gomatrixserverlib.FormatAll),

syncapi/routing/routing.go

@@ -18,15 +18,18 @@ import (
 	"net/http"
 
 	"github.com/gorilla/mux"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	"github.com/matrix-org/dendrite/internal/caching"
+	"github.com/matrix-org/dendrite/internal/fulltext"
 	"github.com/matrix-org/dendrite/internal/httputil"
 	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/sync"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
-	"github.com/matrix-org/gomatrixserverlib"
-	"github.com/matrix-org/util"
 )
 
 // Setup configures the given mux with sync-server listeners
@@ -40,6 +43,7 @@ func Setup(
 	rsAPI api.SyncRoomserverAPI,
 	cfg *config.SyncAPI,
 	lazyLoadCache caching.LazyLoadCache,
+	fts *fulltext.Search,
 ) {
 	v3mux := csMux.PathPrefix("/{apiversion:(?:r0|v3)}/").Subrouter()
 
@@ -95,4 +99,24 @@ func Setup(
 			)
 		}),
 	).Methods(http.MethodGet, http.MethodOptions)
+
+	v3mux.Handle("/search",
+		httputil.MakeAuthAPI("search", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
+			if !cfg.Fulltext.Enabled {
+				return util.JSONResponse{
+					Code: http.StatusNotImplemented,
+					JSON: jsonerror.Unknown("Search has been disabled by the server administrator."),
+				}
+			}
+			var nextBatch *string
+			if err := req.ParseForm(); err != nil {
+				return jsonerror.InternalServerError()
+			}
+			if req.Form.Has("next_batch") {
+				nb := req.FormValue("next_batch")
+				nextBatch = &nb
+			}
+			return Search(req, device, syncDB, fts, nextBatch)
+		}),
+	).Methods(http.MethodPost, http.MethodOptions)
 }

syncapi/routing/search.go

@@ -0,0 +1,344 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// 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 routing
+
+import (
+	"context"
+	"net/http"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/blevesearch/bleve/v2/search"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	"github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+
+	"github.com/matrix-org/dendrite/clientapi/httputil"
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
+	"github.com/matrix-org/dendrite/internal/fulltext"
+	"github.com/matrix-org/dendrite/syncapi/storage"
+	"github.com/matrix-org/dendrite/userapi/api"
+)
+
+// nolint:gocyclo
+func Search(req *http.Request, device *api.Device, syncDB storage.Database, fts *fulltext.Search, from *string) util.JSONResponse {
+	start := time.Now()
+	var (
+		searchReq SearchRequest
+		err       error
+		ctx       = req.Context()
+	)
+	resErr := httputil.UnmarshalJSONRequest(req, &searchReq)
+	if resErr != nil {
+		logrus.Error("failed to unmarshal search request")
+		return *resErr
+	}
+
+	nextBatch := 0
+	if from != nil && *from != "" {
+		nextBatch, err = strconv.Atoi(*from)
+		if err != nil {
+			return jsonerror.InternalServerError()
+		}
+	}
+
+	if searchReq.SearchCategories.RoomEvents.Filter.Limit == 0 {
+		searchReq.SearchCategories.RoomEvents.Filter.Limit = 5
+	}
+
+	// only search rooms the user is actually joined to
+	joinedRooms, err := syncDB.RoomIDsWithMembership(ctx, device.UserID, "join")
+	if err != nil {
+		return jsonerror.InternalServerError()
+	}
+	if len(joinedRooms) == 0 {
+		return util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: jsonerror.NotFound("User not joined to any rooms."),
+		}
+	}
+	joinedRoomsMap := make(map[string]struct{}, len(joinedRooms))
+	for _, roomID := range joinedRooms {
+		joinedRoomsMap[roomID] = struct{}{}
+	}
+	rooms := []string{}
+	if searchReq.SearchCategories.RoomEvents.Filter.Rooms != nil {
+		for _, roomID := range *searchReq.SearchCategories.RoomEvents.Filter.Rooms {
+			if _, ok := joinedRoomsMap[roomID]; ok {
+				rooms = append(rooms, roomID)
+			}
+		}
+	} else {
+		rooms = joinedRooms
+	}
+
+	if len(rooms) == 0 {
+		return util.JSONResponse{
+			Code: http.StatusForbidden,
+			JSON: jsonerror.Unknown("User not allowed to search in this room(s)."),
+		}
+	}
+
+	orderByTime := searchReq.SearchCategories.RoomEvents.OrderBy == "recent"
+
+	result, err := fts.Search(
+		searchReq.SearchCategories.RoomEvents.SearchTerm,
+		rooms,
+		searchReq.SearchCategories.RoomEvents.Keys,
+		searchReq.SearchCategories.RoomEvents.Filter.Limit,
+		nextBatch,
+		orderByTime,
+	)
+	if err != nil {
+		logrus.WithError(err).Error("failed to search fulltext")
+		return jsonerror.InternalServerError()
+	}
+	logrus.Debugf("Search took %s", result.Took)
+
+	// From was specified but empty, return no results, only the count
+	if from != nil && *from == "" {
+		return util.JSONResponse{
+			Code: http.StatusOK,
+			JSON: SearchResponse{
+				SearchCategories: SearchCategories{
+					RoomEvents: RoomEvents{
+						Count:     int(result.Total),
+						NextBatch: nil,
+					},
+				},
+			},
+		}
+	}
+
+	results := []Result{}
+
+	wantEvents := make([]string, 0, len(result.Hits))
+	eventScore := make(map[string]*search.DocumentMatch)
+
+	for _, hit := range result.Hits {
+		wantEvents = append(wantEvents, hit.ID)
+		eventScore[hit.ID] = hit
+	}
+
+	// Filter on m.room.message, as otherwise we also get events like m.reaction
+	// which "breaks" displaying results in Element Web.
+	types := []string{"m.room.message"}
+	roomFilter := &gomatrixserverlib.RoomEventFilter{
+		Rooms: &rooms,
+		Types: &types,
+	}
+
+	evs, err := syncDB.Events(ctx, wantEvents)
+	if err != nil {
+		logrus.WithError(err).Error("failed to get events from database")
+		return jsonerror.InternalServerError()
+	}
+
+	groups := make(map[string]RoomResult)
+	knownUsersProfiles := make(map[string]ProfileInfo)
+
+	// Sort the events by depth, as the returned values aren't ordered
+	if orderByTime {
+		sort.Slice(evs, func(i, j int) bool {
+			return evs[i].Depth() > evs[j].Depth()
+		})
+	}
+
+	stateForRooms := make(map[string][]gomatrixserverlib.ClientEvent)
+	for _, event := range evs {
+		eventsBefore, eventsAfter, err := contextEvents(ctx, syncDB, event, roomFilter, searchReq)
+		if err != nil {
+			logrus.WithError(err).Error("failed to get context events")
+			return jsonerror.InternalServerError()
+		}
+		startToken, endToken, err := getStartEnd(ctx, syncDB, eventsBefore, eventsAfter)
+		if err != nil {
+			logrus.WithError(err).Error("failed to get start/end")
+			return jsonerror.InternalServerError()
+		}
+
+		profileInfos := make(map[string]ProfileInfo)
+		for _, ev := range append(eventsBefore, eventsAfter...) {
+			profile, ok := knownUsersProfiles[event.Sender()]
+			if !ok {
+				stateEvent, err := syncDB.GetStateEvent(ctx, ev.RoomID(), gomatrixserverlib.MRoomMember, ev.Sender())
+				if err != nil {
+					logrus.WithError(err).WithField("user_id", event.Sender()).Warn("failed to query userprofile")
+					continue
+				}
+				if stateEvent == nil {
+					continue
+				}
+				profile = ProfileInfo{
+					AvatarURL:   gjson.GetBytes(stateEvent.Content(), "avatar_url").Str,
+					DisplayName: gjson.GetBytes(stateEvent.Content(), "displayname").Str,
+				}
+				knownUsersProfiles[event.Sender()] = profile
+			}
+			profileInfos[ev.Sender()] = profile
+		}
+
+		results = append(results, Result{
+			Context: SearchContextResponse{
+				Start:        startToken.String(),
+				End:          endToken.String(),
+				EventsAfter:  gomatrixserverlib.HeaderedToClientEvents(eventsAfter, gomatrixserverlib.FormatSync),
+				EventsBefore: gomatrixserverlib.HeaderedToClientEvents(eventsBefore, gomatrixserverlib.FormatSync),
+				ProfileInfo:  profileInfos,
+			},
+			Rank:   eventScore[event.EventID()].Score,
+			Result: gomatrixserverlib.HeaderedToClientEvent(event, gomatrixserverlib.FormatAll),
+		})
+		roomGroup := groups[event.RoomID()]
+		roomGroup.Results = append(roomGroup.Results, event.EventID())
+		groups[event.RoomID()] = roomGroup
+		if _, ok := stateForRooms[event.RoomID()]; searchReq.SearchCategories.RoomEvents.IncludeState && !ok {
+			stateFilter := gomatrixserverlib.DefaultStateFilter()
+			state, err := syncDB.CurrentState(ctx, event.RoomID(), &stateFilter, nil)
+			if err != nil {
+				logrus.WithError(err).Error("unable to get current state")
+				return jsonerror.InternalServerError()
+			}
+			stateForRooms[event.RoomID()] = gomatrixserverlib.HeaderedToClientEvents(state, gomatrixserverlib.FormatSync)
+		}
+	}
+
+	var nextBatchResult *string = nil
+	if int(result.Total) > nextBatch+len(results) {
+		nb := strconv.Itoa(len(results) + nextBatch)
+		nextBatchResult = &nb
+	} else if int(result.Total) == nextBatch+len(results) {
+		// Sytest expects a next_batch even if we don't actually have any more results
+		nb := ""
+		nextBatchResult = &nb
+	}
+
+	res := SearchResponse{
+		SearchCategories: SearchCategories{
+			RoomEvents: RoomEvents{
+				Count:      int(result.Total),
+				Groups:     Groups{RoomID: groups},
+				Results:    results,
+				NextBatch:  nextBatchResult,
+				Highlights: strings.Split(searchReq.SearchCategories.RoomEvents.SearchTerm, " "),
+				State:      stateForRooms,
+			},
+		},
+	}
+
+	logrus.Debugf("Full search request took %v", time.Since(start))
+
+	return util.JSONResponse{
+		Code: http.StatusOK,
+		JSON: res,
+	}
+}
+
+// contextEvents returns the events around a given eventID
+func contextEvents(
+	ctx context.Context,
+	syncDB storage.Database,
+	event *gomatrixserverlib.HeaderedEvent,
+	roomFilter *gomatrixserverlib.RoomEventFilter,
+	searchReq SearchRequest,
+) ([]*gomatrixserverlib.HeaderedEvent, []*gomatrixserverlib.HeaderedEvent, error) {
+	id, _, err := syncDB.SelectContextEvent(ctx, event.RoomID(), event.EventID())
+	if err != nil {
+		logrus.WithError(err).Error("failed to query context event")
+		return nil, nil, err
+	}
+	roomFilter.Limit = searchReq.SearchCategories.RoomEvents.EventContext.BeforeLimit
+	eventsBefore, err := syncDB.SelectContextBeforeEvent(ctx, id, event.RoomID(), roomFilter)
+	if err != nil {
+		logrus.WithError(err).Error("failed to query before context event")
+		return nil, nil, err
+	}
+	roomFilter.Limit = searchReq.SearchCategories.RoomEvents.EventContext.AfterLimit
+	_, eventsAfter, err := syncDB.SelectContextAfterEvent(ctx, id, event.RoomID(), roomFilter)
+	if err != nil {
+		logrus.WithError(err).Error("failed to query after context event")
+		return nil, nil, err
+	}
+	return eventsBefore, eventsAfter, err
+}
+
+type SearchRequest struct {
+	SearchCategories struct {
+		RoomEvents struct {
+			EventContext struct {
+				AfterLimit     int  `json:"after_limit,omitempty"`
+				BeforeLimit    int  `json:"before_limit,omitempty"`
+				IncludeProfile bool `json:"include_profile,omitempty"`
+			} `json:"event_context"`
+			Filter    gomatrixserverlib.StateFilter `json:"filter"`
+			Groupings struct {
+				GroupBy []struct {
+					Key string `json:"key"`
+				} `json:"group_by"`
+			} `json:"groupings"`
+			IncludeState bool     `json:"include_state"`
+			Keys         []string `json:"keys"`
+			OrderBy      string   `json:"order_by"`
+			SearchTerm   string   `json:"search_term"`
+		} `json:"room_events"`
+	} `json:"search_categories"`
+}
+
+type SearchResponse struct {
+	SearchCategories SearchCategories `json:"search_categories"`
+}
+type RoomResult struct {
+	NextBatch *string  `json:"next_batch,omitempty"`
+	Order     int      `json:"order"`
+	Results   []string `json:"results"`
+}
+
+type Groups struct {
+	RoomID map[string]RoomResult `json:"room_id"`
+}
+
+type Result struct {
+	Context SearchContextResponse         `json:"context"`
+	Rank    float64                       `json:"rank"`
+	Result  gomatrixserverlib.ClientEvent `json:"result"`
+}
+
+type SearchContextResponse struct {
+	End          string                          `json:"end"`
+	EventsAfter  []gomatrixserverlib.ClientEvent `json:"events_after"`
+	EventsBefore []gomatrixserverlib.ClientEvent `json:"events_before"`
+	Start        string                          `json:"start"`
+	ProfileInfo  map[string]ProfileInfo          `json:"profile_info"`
+}
+
+type ProfileInfo struct {
+	AvatarURL   string `json:"avatar_url"`
+	DisplayName string `json:"display_name"`
+}
+
+type RoomEvents struct {
+	Count      int                                        `json:"count"`
+	Groups     Groups                                     `json:"groups"`
+	Highlights []string                                   `json:"highlights"`
+	NextBatch  *string                                    `json:"next_batch,omitempty"`
+	Results    []Result                                   `json:"results"`
+	State      map[string][]gomatrixserverlib.ClientEvent `json:"state,omitempty"`
+}
+type SearchCategories struct {
+	RoomEvents RoomEvents `json:"room_events"`
+}

syncapi/storage/interface.go

@@ -161,6 +161,7 @@ type Database interface {
 	// returns "leave", the topological position and no error. If an error occurs, other than sql.ErrNoRows, returns that and an empty
 	// string as the membership.
 	SelectMembershipForUser(ctx context.Context, roomID, userID string, pos int64) (membership string, topologicalPos int, err error)
+	ReIndex(ctx context.Context, limit, afterID int64) (map[int64]gomatrixserverlib.HeaderedEvent, error)
 }
 
 type Presence interface {

syncapi/storage/postgres/output_room_events_table.go

@@ -166,6 +166,8 @@ const selectContextAfterEventSQL = "" +
 	" AND ( $7::text[] IS NULL OR NOT(type LIKE ANY($7)) )" +
 	" ORDER BY id ASC LIMIT $3"
 
+const selectSearchSQL = "SELECT id, event_id, headered_event_json FROM syncapi_output_room_events WHERE id > $1 AND type = ANY($2) ORDER BY id ASC LIMIT $3"
+
 type outputRoomEventsStatements struct {
 	insertEventStmt               *sql.Stmt
 	selectEventsStmt              *sql.Stmt
@@ -180,6 +182,7 @@ type outputRoomEventsStatements struct {
 	selectContextEventStmt        *sql.Stmt
 	selectContextBeforeEventStmt  *sql.Stmt
 	selectContextAfterEventStmt   *sql.Stmt
+	selectSearchStmt              *sql.Stmt
 }
 
 func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
@@ -215,6 +218,7 @@ func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
 		{&s.selectContextEventStmt, selectContextEventSQL},
 		{&s.selectContextBeforeEventStmt, selectContextBeforeEventSQL},
 		{&s.selectContextAfterEventStmt, selectContextAfterEventSQL},
+		{&s.selectSearchStmt, selectSearchSQL},
 	}.Prepare(db)
 }
 
@@ -632,3 +636,27 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 	}
 	return result, rows.Err()
 }
+
+func (s *outputRoomEventsStatements) ReIndex(ctx context.Context, txn *sql.Tx, limit, afterID int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectSearchStmt).QueryContext(ctx, afterID, pq.StringArray(types), limit)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "rows.close() failed")
+
+	var eventID string
+	var id int64
+	result := make(map[int64]gomatrixserverlib.HeaderedEvent)
+	for rows.Next() {
+		var ev gomatrixserverlib.HeaderedEvent
+		var eventBytes []byte
+		if err = rows.Scan(&id, &eventID, &eventBytes); err != nil {
+			return nil, err
+		}
+		if err = ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+		result[id] = ev
+	}
+	return result, rows.Err()
+}

syncapi/storage/shared/syncserver.go

@@ -1093,3 +1093,11 @@ func (d *Database) MaxStreamPositionForPresence(ctx context.Context) (types.Stre
 func (d *Database) SelectMembershipForUser(ctx context.Context, roomID, userID string, pos int64) (membership string, topologicalPos int, err error) {
 	return d.Memberships.SelectMembershipForUser(ctx, nil, roomID, userID, pos)
 }
+
+func (s *Database) ReIndex(ctx context.Context, limit, afterID int64) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	return s.OutputEvents.ReIndex(ctx, nil, limit, afterID, []string{
+		gomatrixserverlib.MRoomName,
+		gomatrixserverlib.MRoomTopic,
+		"m.room.message",
+	})
+}

syncapi/storage/sqlite3/output_room_events_table.go

@@ -115,6 +115,8 @@ const selectContextAfterEventSQL = "" +
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
+const selectSearchSQL = "SELECT id, event_id, headered_event_json FROM syncapi_output_room_events WHERE type IN ($1) AND id > $2 LIMIT $3 ORDER BY id ASC"
+
 type outputRoomEventsStatements struct {
 	db                           *sql.DB
 	streamIDStatements           *StreamIDStatements
@@ -125,6 +127,7 @@ type outputRoomEventsStatements struct {
 	selectContextEventStmt       *sql.Stmt
 	selectContextBeforeEventStmt *sql.Stmt
 	selectContextAfterEventStmt  *sql.Stmt
+	//selectSearchStmt             *sql.Stmt - prepared at runtime
 }
 
 func NewSqliteEventsTable(db *sql.DB, streamID *StreamIDStatements) (tables.Events, error) {
@@ -157,6 +160,7 @@ func NewSqliteEventsTable(db *sql.DB, streamID *StreamIDStatements) (tables.Even
 		{&s.selectContextEventStmt, selectContextEventSQL},
 		{&s.selectContextBeforeEventStmt, selectContextBeforeEventSQL},
 		{&s.selectContextAfterEventStmt, selectContextAfterEventSQL},
+		//{&s.selectSearchStmt, selectSearchSQL}, - prepared at runtime
 	}.Prepare(db)
 }
 
@@ -628,3 +632,40 @@ func unmarshalStateIDs(addIDsJSON, delIDsJSON string) (addIDs []string, delIDs [
 	}
 	return
 }
+
+func (s *outputRoomEventsStatements) ReIndex(ctx context.Context, txn *sql.Tx, limit, afterID int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	params := make([]interface{}, len(types))
+	for i := range types {
+		params[i] = types[i]
+	}
+	params = append(params, afterID)
+	params = append(params, limit)
+	selectSQL := strings.Replace(selectSearchSQL, "($1)", sqlutil.QueryVariadic(len(types)), 1)
+
+	stmt, err := s.db.Prepare(selectSQL)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, stmt, "selectEvents: stmt.close() failed")
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "rows.close() failed")
+
+	var eventID string
+	var id int64
+	result := make(map[int64]gomatrixserverlib.HeaderedEvent)
+	for rows.Next() {
+		var ev gomatrixserverlib.HeaderedEvent
+		var eventBytes []byte
+		if err = rows.Scan(&id, &eventID, &eventBytes); err != nil {
+			return nil, err
+		}
+		if err = ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+		result[id] = ev
+	}
+	return result, rows.Err()
+}

syncapi/storage/tables/interface.go

@@ -75,6 +75,7 @@ type Events interface {
 	SelectContextEvent(ctx context.Context, txn *sql.Tx, roomID, eventID string) (int, gomatrixserverlib.HeaderedEvent, error)
 	SelectContextBeforeEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) ([]*gomatrixserverlib.HeaderedEvent, error)
 	SelectContextAfterEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) (int, []*gomatrixserverlib.HeaderedEvent, error)
+	ReIndex(ctx context.Context, txn *sql.Tx, limit, offset int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error)
 }
 
 // Topology keeps track of the depths and stream positions for all events.

syncapi/syncapi.go

@@ -88,14 +88,15 @@ func AddPublicRoutes(
 
 	roomConsumer := consumers.NewOutputRoomEventConsumer(
 		base.ProcessContext, cfg, js, syncDB, notifier, streams.PDUStreamProvider,
-		streams.InviteStreamProvider, rsAPI,
+		streams.InviteStreamProvider, rsAPI, base.Fulltext,
 	)
 	if err = roomConsumer.Start(); err != nil {
 		logrus.WithError(err).Panicf("failed to start room server consumer")
 	}
 
 	clientConsumer := consumers.NewOutputClientDataConsumer(
-		base.ProcessContext, cfg, js, syncDB, notifier, streams.AccountDataStreamProvider,
+		base.ProcessContext, cfg, js, natsClient, syncDB, notifier,
+		streams.AccountDataStreamProvider, base.Fulltext,
 	)
 	if err = clientConsumer.Start(); err != nil {
 		logrus.WithError(err).Panicf("failed to start client data consumer")
@@ -131,6 +132,6 @@ func AddPublicRoutes(
 
 	routing.Setup(
 		base.PublicClientAPIMux, requestPool, syncDB, userAPI,
-		rsAPI, cfg, base.Caches,
+		rsAPI, cfg, base.Caches, base.Fulltext,
 	)
 }