Added feature to sync channel topic/purpose between Slack bridges. [#585]

bridge/config/config.go

@@ -117,6 +117,7 @@ type Protocol struct {
 	ShowEmbeds             bool       // discord
 	SkipTLSVerify          bool       // IRC, mattermost
 	StripNick              bool       // all protocols
+	SyncTopicChange        bool       // slack
 	Team                   string     // mattermost
 	Token                  string     // gitter, slack, discord, api
 	Topic                  string     // zulip

bridge/slack/handlers.go

@@ -116,6 +116,11 @@ func (b *Bslack) skipMessageEvent(ev *slack.MessageEvent) bool {
 		return b.GetBool(noSendJoinConfig)
 	case sPinnedItem, sUnpinnedItem:
 		return true
+	case sChannelTopic, sChannelPurpose:
+		// Skip the event if our bot/user account changed the topic/purpose
+		if ev.User == b.si.User.ID {
+			return true
+		}
 	}
 
 	// Skip any messages that we made ourselves or from 'slackbot' (see #527).
@@ -201,6 +206,7 @@ func (b *Bslack) handleStatusEvent(ev *slack.MessageEvent, rmsg *config.Message)
 		rmsg.Username = sSystemUser
 		rmsg.Event = config.EventJoinLeave
 	case sChannelTopic, sChannelPurpose:
+		b.populateChannels()
 		rmsg.Event = config.EventTopicChange
 	case sMessageChanged:
 		rmsg.Text = ev.SubMessage.Text

bridge/slack/helpers.go

@@ -266,8 +266,18 @@ var (
 	channelRE  = regexp.MustCompile(`<#[a-zA-Z0-9]+\|(.+?)>`)
 	variableRE = regexp.MustCompile(`<!((?:subteam\^)?[a-zA-Z0-9]+)(?:\|@?(.+?))?>`)
 	urlRE      = regexp.MustCompile(`<(.*?)(\|.*?)?>`)
+	topicOrPurposeRE    = regexp.MustCompile(`(?s)^@.+ set the channel (topic|purpose): (.+?)(\[nosync\])?$`)
 )
 
+func (b *Bslack) extractTopicOrPurpose(text string) (updateType string, extracted string) {
+	r := topicOrPurposeRE.FindStringSubmatch(text)
+	updateType, extracted, noSync := r[1], r[2], r[3]
+	if noSync != "" {
+		return "nosync", ""
+	}
+	return updateType, extracted
+}
+
 // @see https://api.slack.com/docs/message-formatting#linking_to_channels_and_users
 func (b *Bslack) replaceMention(text string) string {
 	replaceFunc := func(match string) string {

bridge/slack/slack.go

@@ -280,6 +280,24 @@ func (b *Bslack) sendRTM(msg config.Message) (string, error) {
 		}
 		return "", nil
 	}
+	if (msg.Event == config.EVENT_TOPIC_CHANGE) && b.GetBool("SyncTopicChange") {
+		incomingChangeType, text := b.extractTopicOrPurpose(msg.Text)
+		switch incomingChangeType {
+		case "topic":
+			if strings.HasSuffix(channelInfo.Topic.Value, "[nosync]") {
+				break
+			}
+			b.rtm.SetTopicOfConversation(channelInfo.ID, text)
+		case "purpose":
+			if strings.HasSuffix(channelInfo.Purpose.Value, "[nosync]") {
+				break
+			}
+			b.rtm.SetPurposeOfConversation(channelInfo.ID, text)
+		case "nosync":
+			break
+		}
+		return "", nil
+	}
 
 	// Handle message deletions.
 	var handled bool

matterbridge.toml.sample

@@ -765,11 +765,17 @@ ShowJoinPart=false
 #OPTIONAL (default false)
 StripNick=false
 
-#Enable to show topic changes from other bridges 
+#Enable to show topic/purpose changes from other bridges
 #Only works hiding/show topic changes from slack bridge for now
 #OPTIONAL (default false)
 ShowTopicChange=false
 
+#Enable to sync topic/purpose changes from other bridges
+#Only works syncing topic changes from slack bridge for now
+#Appending "[nosync]" to the topic/purpose will protect it from being synced
+#OPTIONAL (default false)
+SyncTopicChange=false
+
 ###################################################################
 #telegram section
 ###################################################################