Add relay mode (#392)

commands.go

@@ -49,6 +49,8 @@ func (br *SignalBridge) RegisterCommands() {
 		cmdLogin,
 		cmdPM,
 		cmdDisconnect,
+		cmdSetRelay,
+		cmdUnsetRelay,
 	)
 }
 
@@ -64,6 +66,51 @@ func wrapCommand(handler func(*WrappedCommandEvent)) func(*commands.Event) {
 	}
 }
 
+var cmdSetRelay = &commands.FullHandler{
+	Func: wrapCommand(fnSetRelay),
+	Name: "set-relay",
+	Help: commands.HelpMeta{
+		Section:     HelpSectionPortalManagement,
+		Description: "Relay messages in this room through your Signal account.",
+	},
+	RequiresPortal: true,
+	RequiresLogin:  true,
+}
+
+func fnSetRelay(ce *WrappedCommandEvent) {
+	if !ce.Bridge.Config.Bridge.Relay.Enabled {
+		ce.Reply("Relay mode is not enabled on this instance of the bridge")
+	} else if ce.Bridge.Config.Bridge.Relay.AdminOnly && !ce.User.Admin {
+		ce.Reply("Only bridge admins are allowed to enable relay mode on this instance of the bridge")
+	} else {
+		ce.Portal.RelayUserID = ce.User.MXID
+		ce.Portal.Update()
+		ce.Reply("Messages from non-logged-in users in this room will now be bridged through your Signal account")
+	}
+}
+
+var cmdUnsetRelay = &commands.FullHandler{
+	Func: wrapCommand(fnUnsetRelay),
+	Name: "unset-relay",
+	Help: commands.HelpMeta{
+		Section:     HelpSectionPortalManagement,
+		Description: "Stop relaying messages in this room.",
+	},
+	RequiresPortal: true,
+}
+
+func fnUnsetRelay(ce *WrappedCommandEvent) {
+	if !ce.Bridge.Config.Bridge.Relay.Enabled {
+		ce.Reply("Relay mode is not enabled on this instance of the bridge")
+	} else if ce.Bridge.Config.Bridge.Relay.AdminOnly && !ce.User.Admin {
+		ce.Reply("Only bridge admins are allowed to enable relay mode on this instance of the bridge")
+	} else {
+		ce.Portal.RelayUserID = ""
+		ce.Portal.Update()
+		ce.Reply("Messages from non-logged-in users will no longer be bridged in this room")
+	}
+}
+
 var cmdDisconnect = &commands.FullHandler{
 	Func: wrapCommand(fnDisconnect),
 	Name: "disconnect",

config/bridge.go

@@ -24,6 +24,8 @@ import (
 	"time"
 
 	"maunium.net/go/mautrix/bridge/bridgeconfig"
+	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 
 	"go.mau.fi/mautrix-signal/pkg/signalmeow"
 )
@@ -68,6 +70,8 @@ type BridgeConfig struct {
 
 	Permissions bridgeconfig.PermissionConfig `yaml:"permissions"`
 
+	Relay RelaybotConfig `yaml:"relay"`
+
 	usernameTemplate    *template.Template `yaml:"-"`
 	displaynameTemplate *template.Template `yaml:"-"`
 }
@@ -169,3 +173,57 @@ func (bc BridgeConfig) FormatDisplayname(contact *signalmeow.Contact) string {
 	})
 	return buffer.String()
 }
+
+type RelaybotConfig struct {
+	Enabled          bool                         `yaml:"enabled"`
+	AdminOnly        bool                         `yaml:"admin_only"`
+	MessageFormats   map[event.MessageType]string `yaml:"message_formats"`
+	messageTemplates *template.Template           `yaml:"-"`
+}
+
+type umRelaybotConfig RelaybotConfig
+
+func (rc *RelaybotConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	err := unmarshal((*umRelaybotConfig)(rc))
+	if err != nil {
+		return err
+	}
+
+	rc.messageTemplates = template.New("messageTemplates")
+	for key, format := range rc.MessageFormats {
+		_, err := rc.messageTemplates.New(string(key)).Parse(format)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+type Sender struct {
+	UserID string
+	event.MemberEventContent
+}
+
+type formatData struct {
+	Sender  Sender
+	Message string
+	Content *event.MessageEventContent
+}
+
+func (rc *RelaybotConfig) FormatMessage(content *event.MessageEventContent, sender id.UserID, member event.MemberEventContent) (string, error) {
+	if len(member.Displayname) == 0 {
+		member.Displayname = sender.String()
+	}
+	member.Displayname = template.HTMLEscapeString(member.Displayname)
+	var output strings.Builder
+	err := rc.messageTemplates.ExecuteTemplate(&output, string(content.MsgType), formatData{
+		Sender: Sender{
+			UserID:             template.HTMLEscapeString(sender.String()),
+			MemberEventContent: member,
+		},
+		Content: content,
+		Message: content.FormattedBody,
+	})
+	return output.String(), err
+}

config/upgrade.go

@@ -128,6 +128,9 @@ func DoUpgrade(helper *up.Helper) {
 	helper.Copy(up.Bool, "bridge", "provisioning", "debug_endpoints")
 
 	helper.Copy(up.Map, "bridge", "permissions")
+	helper.Copy(up.Bool, "bridge", "relay", "enabled")
+	helper.Copy(up.Bool, "bridge", "relay", "admin_only")
+	helper.Copy(up.Map, "bridge", "relay", "message_formats")
 }
 
 var SpacedBlocks = [][]string{

example-config.yaml

@@ -262,6 +262,24 @@ bridge:
         "example.com": user
         "@admin:example.com": admin
 
+    # Settings for relay mode
+    relay:
+        # Whether relay mode should be allowed. If allowed, `!wa set-relay` can be used to turn any
+        # authenticated user into a relaybot for that chat.
+        enabled: false
+        # Should only admins be allowed to set themselves as relay users?
+        admin_only: true
+        # The formats to use when sending messages to Signal via the relaybot.
+        message_formats:
+            m.text: "<b>{{ .Sender.Displayname }}</b>: {{ .Message }}"
+            m.notice: "<b>{{ .Sender.Displayname }}</b>: {{ .Message }}"
+            m.emote: "* <b>{{ .Sender.Displayname }}</b> {{ .Message }}"
+            m.file: "<b>{{ .Sender.Displayname }}</b> sent a file"
+            m.image: "<b>{{ .Sender.Displayname }}</b> sent an image"
+            m.audio: "<b>{{ .Sender.Displayname }}</b> sent an audio file"
+            m.video: "<b>{{ .Sender.Displayname }}</b> sent a video"
+            m.location: "<b>{{ .Sender.Displayname }}</b> sent a location"
+
 # Logging config. See https://github.com/tulir/zeroconfig for details.
 logging:
     min_level: debug

messagetracking.go

@@ -33,6 +33,7 @@ var (
 	errUserNotConnected            = errors.New("you are not connected to Signal")
 	errDifferentUser               = errors.New("user is not the recipient of this private chat portal")
 	errUserNotLoggedIn             = errors.New("user is not logged in and chat has no relay bot")
+	errRelaybotNotLoggedIn         = errors.New("neither user nor relay bot of chat are logged in")
 	errMNoticeDisabled             = errors.New("bridging m.notice messages is disabled")
 	errUnexpectedParsedContentType = errors.New("unexpected parsed content type")
 	errInvalidGeoURI               = errors.New("invalid `geo:` URI in message")
@@ -96,7 +97,8 @@ func errorToStatusReason(err error) (reason event.MessageStatusReason, status ev
 	case errors.Is(err, errUserNotConnected):
 		return event.MessageStatusGenericError, event.MessageStatusRetriable, true, true, ""
 	case errors.Is(err, errUserNotLoggedIn),
-		errors.Is(err, errDifferentUser):
+		errors.Is(err, errDifferentUser),
+		errors.Is(err, errRelaybotNotLoggedIn):
 		return event.MessageStatusGenericError, event.MessageStatusRetriable, true, false, ""
 	default:
 		return event.MessageStatusGenericError, event.MessageStatusRetriable, false, true, ""
@@ -267,8 +269,7 @@ func (mt *messageTimings) String() string {
 	mt.preproc = niceRound(mt.preproc)
 	mt.convert = niceRound(mt.convert)
 	mt.totalSend = niceRound(mt.totalSend)
-	whatsmeowTimings := "N/A"
-	return fmt.Sprintf("BRIDGE: receive: %s, decrypt: %s, queue: %s, total hs->portal: %s, implicit rr: %s -- PORTAL: preprocess: %s, convert: %s, total send: %s -- WHATSMEOW: %s", mt.initReceive, mt.decrypt, mt.implicitRR, mt.portalQueue, mt.totalReceive, mt.preproc, mt.convert, mt.totalSend, whatsmeowTimings)
+	return fmt.Sprintf("BRIDGE: receive: %s, decrypt: %s, queue: %s, total hs->portal: %s, implicit rr: %s -- PORTAL: preprocess: %s, convert: %s, total send: %s ", mt.initReceive, mt.decrypt, mt.implicitRR, mt.portalQueue, mt.totalReceive, mt.preproc, mt.convert, mt.totalSend)
 }
 
 type metricSender struct {

portal.go

@@ -85,6 +85,8 @@ type Portal struct {
 	currentlyTypingLock sync.Mutex
 
 	latestReadTimestamp uint64 // Cache the latest read timestamp to avoid unnecessary read receipts
+
+	relayUser *User
 }
 
 const recentMessageBufferSize = 32
@@ -117,11 +119,20 @@ func (portal *Portal) MarkEncrypted() {
 }
 
 func (portal *Portal) ReceiveMatrixEvent(user bridge.User, evt *event.Event) {
-	if user.GetPermissionLevel() >= bridgeconfig.PermissionLevelUser {
+	if user.GetPermissionLevel() >= bridgeconfig.PermissionLevelUser || portal.HasRelaybot() {
 		portal.matrixMessages <- portalMatrixMessage{user: user.(*User), evt: evt}
 	}
 }
 
+func (portal *Portal) GetRelayUser() *User {
+	if !portal.HasRelaybot() {
+		return nil
+	} else if portal.relayUser == nil {
+		portal.relayUser = portal.bridge.GetUserByMXID(portal.RelayUserID)
+	}
+	return portal.relayUser
+}
+
 func isUUID(s string) bool {
 	if _, uuidErr := uuid.Parse(s); uuidErr == nil {
 		return true
@@ -263,7 +274,7 @@ func (portal *Portal) messageLoop() {
 func (portal *Portal) handleMatrixMessages(msg portalMatrixMessage) {
 	// If we have no SignalDevice, the bridge isn't logged in properly,
 	// so send BAD_CREDENTIALS so the user knows
-	if !msg.user.SignalDevice.IsDeviceLoggedIn() {
+	if !msg.user.SignalDevice.IsDeviceLoggedIn() && !portal.HasRelaybot() {
 		go portal.sendMessageMetrics(msg.evt, errUserNotLoggedIn, "Ignoring", nil)
 		msg.user.BridgeState.Send(status.BridgeState{StateEvent: status.StateBadCredentials, Message: "You have been logged out of Signal, please reconnect"})
 		return
@@ -367,7 +378,9 @@ func (portal *Portal) handleMatrixMessage(sender *User, evt *event.Event) {
 	if portal.ExpirationTime > 0 {
 		signalmeow.AddExpiryToDataMessage(msg, uint32(portal.ExpirationTime))
 	}
-
+	if !sender.IsLoggedIn() {
+		sender = portal.GetRelayUser()
+	}
 	err = portal.sendSignalMessage(ctx, msg, sender, evt.ID)
 
 	timings.totalSend = time.Since(start)
@@ -397,6 +410,10 @@ func (portal *Portal) handleMatrixRedaction(sender *User, evt *event.Event) {
 		return
 	}
 
+	if !sender.IsLoggedIn() {
+		sender = portal.GetRelayUser()
+	}
+
 	// If this is a message redaction, send a redaction to Signal
 	if dbMessage != nil {
 		msg := signalmeow.DataMessageForDelete(dedupedTimestamp(dbMessage))
@@ -428,6 +445,10 @@ func (portal *Portal) handleMatrixReaction(sender *User, evt *event.Event) {
 	// Find the original signal message based on eventID
 	relatedEventID := evt.Content.AsReaction().RelatesTo.EventID
 	dbMessage := portal.bridge.DB.Message.GetByMXID(relatedEventID)
+	if !sender.IsLoggedIn() {
+		portal.log.Error().Msgf("Cannot relay reaction from non-logged-in user. Ignoring")
+		return
+	}
 	if dbMessage == nil {
 		portal.sendMessageStatusCheckpointFailed(evt, errors.New("could not find original message for reaction"))
 		portal.log.Error().Msgf("Could not find original message for reaction %s", evt.ID)
@@ -438,6 +459,7 @@ func (portal *Portal) handleMatrixReaction(sender *User, evt *event.Event) {
 	targetAuthorUUID := dbMessage.Sender
 	targetTimestamp := dedupedTimestamp(dbMessage)
 	msg := signalmeow.DataMessageForReaction(signalEmoji, targetAuthorUUID, targetTimestamp, false)
+
 	err := portal.sendSignalMessage(context.Background(), msg, sender, evt.ID)
 	if err != nil {
 		portal.sendMessageStatusCheckpointFailed(evt, err)
@@ -624,15 +646,39 @@ func (portal *Portal) convertMatrixMessage(ctx context.Context, sender *User, ev
 	if evt.Type == event.EventSticker {
 		content.MsgType = event.MessageType(event.EventSticker.Type)
 	}
-
+	realSenderMXID := sender.MXID
+	isRelay := false
+	if !sender.IsLoggedIn() {
+		if !portal.HasRelaybot() {
+			return nil, errUserNotLoggedIn
+		}
+		sender = portal.GetRelayUser()
+		if !sender.IsLoggedIn() {
+			return nil, errRelaybotNotLoggedIn
+		}
+		isRelay = true
+	}
 	var outgoingMessage *signalmeow.SignalContent
+	relaybotFormatted := isRelay && portal.addRelaybotFormat(realSenderMXID, content)
+	if relaybotFormatted && content.FileName == "" {
+		content.FileName = content.Body
+	}
+
+	if evt.Type == event.EventSticker {
+		if relaybotFormatted {
+			// Stickers can't have captions, so force relaybot stickers to be images
+			content.MsgType = event.MsgImage
+		} else {
+			content.MsgType = event.MessageType(event.EventSticker.Type)
+		}
+	}
 
 	switch content.MsgType {
 	case event.MsgText, event.MsgEmote, event.MsgNotice:
 		if content.MsgType == event.MsgNotice && !portal.bridge.Config.Bridge.BridgeNotices {
 			return nil, errMNoticeDisabled
 		}
-		if content.MsgType == event.MsgEmote {
+		if content.MsgType == event.MsgEmote && !relaybotFormatted {
 			content.Body = "/me " + content.Body
 			if content.FormattedBody != "" {
 				content.FormattedBody = "/me " + content.FormattedBody
@@ -1836,3 +1882,21 @@ func (portal *Portal) HandleNewDisappearingMessageTime(newTimer uint32) {
 		intent.SendNotice(portal.MXID, fmt.Sprintf("Disappearing messages set to %s", exfmt.Duration(time.Duration(newTimer)*time.Second)))
 	}
 }
+
+func (portal *Portal) HasRelaybot() bool {
+	return portal.bridge.Config.Bridge.Relay.Enabled && len(portal.RelayUserID) > 0
+}
+
+func (portal *Portal) addRelaybotFormat(userID id.UserID, content *event.MessageEventContent) bool {
+	member := portal.MainIntent().Member(portal.MXID, userID)
+	if member == nil {
+		member = &event.MemberEventContent{}
+	}
+	content.EnsureHasHTML()
+	data, err := portal.bridge.Config.Bridge.Relay.FormatMessage(content, userID, *member)
+	if err != nil {
+		portal.log.Err(err).Msg("Failed to apply relaybot format")
+	}
+	content.FormattedBody = data
+	return true
+}

user.go

@@ -54,6 +54,7 @@ type User struct {
 	bridge *SignalBridge
 	log    zerolog.Logger
 
+	Admin           bool
 	PermissionLevel bridgeconfig.PermissionLevel
 
 	SignalDevice *signalmeow.Device
@@ -187,6 +188,7 @@ func (br *SignalBridge) NewUser(dbUser *database.User) *User {
 
 		PermissionLevel: br.Config.Bridge.Permissions.Get(dbUser.MXID),
 	}
+	user.Admin = user.PermissionLevel >= bridgeconfig.PermissionLevelAdmin
 	user.BridgeState = br.NewBridgeStateQueue(user)
 	return user
 }