matrix: send the display name (the nickname in matrix parlance) instead of the user name

There is also the option UseUserName (already in use by the discord bridge) to turn back to the old behavior.

bridge/config/config.go

@@ -154,7 +154,7 @@ type Protocol struct {
 	UseTLS                 bool       // IRC
 	UseDiscriminator       bool       // discord
 	UseFirstName           bool       // telegram
-	UseUserName            bool       // discord
+	UseUserName            bool       // discord, matrix
 	UseInsecureURL         bool       // telegram
 	VerboseJoinPart        bool       // IRC
 	WebhookBindAddress     string     // mattermost, slack

bridge/matrix/matrix.go

@@ -22,10 +22,16 @@ var (
 	htmlReplacementTag = regexp.MustCompile("<[^>]*>")
 )
 
+type NicknameCacheEntry struct {
+	nickname    string
+	lastUpdated time.Time
+}
+
 type Bmatrix struct {
-	mc      *matrix.Client
-	UserID  string
-	RoomMap map[string]string
+	mc          *matrix.Client
+	UserID      string
+	NicknameMap map[string]NicknameCacheEntry
+	RoomMap     map[string]string
 	sync.RWMutex
 	*bridge.Config
 }
@@ -60,6 +66,7 @@ func newMatrixUsername(username string) *matrixUsername {
 func New(cfg *bridge.Config) bridge.Bridger {
 	b := &Bmatrix{Config: cfg}
 	b.RoomMap = make(map[string]string)
+	b.NicknameMap = make(map[string]NicknameCacheEntry)
 	return b
 }
 
@@ -296,6 +303,43 @@ func (b *Bmatrix) handleEdit(ev *matrix.Event, rmsg config.Message) bool {
 	return true
 }
 
+func (b *Bmatrix) getUserName(mxid string) string {
+	if b.GetBool("UseUserName") {
+		return mxid[1:]
+	}
+
+	b.RLock()
+	if val, present := b.NicknameMap[mxid]; present {
+		if time.Since(val.lastUpdated) < 10*time.Minute {
+			b.RUnlock()
+			return val.nickname
+		}
+	}
+	b.RUnlock()
+
+	nickname, err := b.mc.GetDisplayName(mxid)
+	if err != nil && err.(matrix.HTTPError).Code != 404 {
+		b.Log.Warnf("Couldn't retrieve the display name for %s", mxid)
+	}
+
+	b.Lock()
+	defer b.Unlock()
+
+	if err != nil {
+		b.NicknameMap[mxid] = NicknameCacheEntry{
+			nickname:    mxid[1:],
+			lastUpdated: time.Now(),
+		}
+	} else {
+		b.NicknameMap[mxid] = NicknameCacheEntry{
+			nickname:    nickname.DisplayName,
+			lastUpdated: time.Now(),
+		}
+	}
+
+	return b.NicknameMap[mxid].nickname
+}
+
 func (b *Bmatrix) handleEvent(ev *matrix.Event) {
 	b.Log.Debugf("== Receiving event: %#v", ev)
 	if ev.Sender != b.UserID {
@@ -309,7 +353,7 @@ func (b *Bmatrix) handleEvent(ev *matrix.Event) {
 
 		// Create our message
 		rmsg := config.Message{
-			Username: ev.Sender[1:],
+			Username: b.getUserName(ev.Sender),
 			Channel:  channel,
 			Account:  b.Account,
 			UserID:   ev.Sender,

matterbridge.toml.sample

@@ -1231,6 +1231,9 @@ HTMLDisable=false
 ## RELOADABLE SETTINGS
 ## Settings below can be reloaded by editing the file
 
+# UseUserName shows the username instead of the server nickname
+UseUserName=false
+
 #Whether to prefix messages from other bridges to matrix with the sender's nick.
 #Useful if username overrides for incoming webhooks isn't enabled on the
 #matrix server. If you set PrefixMessagesWithNick to true, each message