Add Mumble support (#1245)

4 files changed, 493 insertions, 0 deletions

diff --git a/bridge/config/config.go b/bridge/config/config.go
index f34da511..a1bce8dc 100644
--- a/bridge/config/config.go
+++ b/bridge/config/config.go
@@ -213,6 +213,7 @@ type BridgeValues struct {
 	WhatsApp           map[string]Protocol // TODO is this struct used? Search for "SlackLegacy" for example didn't return any results
 	Zulip              map[string]Protocol
 	Keybase            map[string]Protocol
+	Mumble             map[string]Protocol
 	General            Protocol
 	Tengo              Tengo
 	Gateway            []Gateway
diff --git a/bridge/mumble/handlers.go b/bridge/mumble/handlers.go
new file mode 100644
index 00000000..a6845955
--- /dev/null
+++ b/bridge/mumble/handlers.go
@@ -0,0 +1,90 @@
+package bmumble
+
+import (
+	"strconv"
+	"time"
+
+	"layeh.com/gumble/gumble"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+)
+
+func (b *Bmumble) handleServerConfig(event *gumble.ServerConfigEvent) {
+	b.serverConfigUpdate <- *event
+}
+
+func (b *Bmumble) handleTextMessage(event *gumble.TextMessageEvent) {
+	sender := "unknown"
+	if event.TextMessage.Sender != nil {
+		sender = event.TextMessage.Sender.Name
+	}
+	// Convert Mumble HTML messages to markdown
+	parts, err := b.convertHTMLtoMarkdown(event.TextMessage.Message)
+	if err != nil {
+		b.Log.Error(err)
+	}
+	now := time.Now().UTC()
+	for i, part := range parts {
+		// Construct matterbridge message and pass on to the gateway
+		rmsg := config.Message{
+			Channel:  strconv.FormatUint(uint64(event.Client.Self.Channel.ID), 10),
+			Username: sender,
+			UserID:   sender + "@" + b.Host,
+			Account:  b.Account,
+		}
+		if part.Image == nil {
+			rmsg.Text = part.Text
+		} else {
+			fname := b.Account + "_" + strconv.FormatInt(now.UnixNano(), 10) + "_" + strconv.Itoa(i) + part.FileExtension
+			rmsg.Extra = make(map[string][]interface{})
+			if err = helper.HandleDownloadSize(b.Log, &rmsg, fname, int64(len(part.Image)), b.General); err != nil {
+				b.Log.WithError(err).Warn("not including image in message")
+				continue
+			}
+			helper.HandleDownloadData(b.Log, &rmsg, fname, "", "", &part.Image, b.General)
+		}
+		b.Log.Debugf("Sending message to gateway: %+v", rmsg)
+		b.Remote <- rmsg
+	}
+}
+
+func (b *Bmumble) handleConnect(event *gumble.ConnectEvent) {
+	// Set the user's "bio"/comment
+	if comment := b.GetString("UserComment"); comment != "" && event.Client.Self != nil {
+		event.Client.Self.SetComment(comment)
+	}
+	// No need to talk or listen
+	event.Client.Self.SetSelfDeafened(true)
+	event.Client.Self.SetSelfMuted(true)
+	// if the Channel variable is set, this is a reconnect -> rejoin channel
+	if b.Channel != nil {
+		if err := b.doJoin(event.Client, *b.Channel); err != nil {
+			b.Log.Error(err)
+		}
+		b.Remote <- config.Message{
+			Username: "system",
+			Text:     "rejoin",
+			Channel:  "",
+			Account:  b.Account,
+			Event:    config.EventRejoinChannels,
+		}
+	}
+}
+
+func (b *Bmumble) handleUserChange(event *gumble.UserChangeEvent) {
+	// Only care about changes to self
+	if event.User != event.Client.Self {
+		return
+	}
+	// Someone attempted to move the user out of the configured channel; attempt to join back
+	if b.Channel != nil {
+		if err := b.doJoin(event.Client, *b.Channel); err != nil {
+			b.Log.Error(err)
+		}
+	}
+}
+
+func (b *Bmumble) handleDisconnect(event *gumble.DisconnectEvent) {
+	b.connected <- *event
+}
diff --git a/bridge/mumble/helpers.go b/bridge/mumble/helpers.go
new file mode 100644
index 00000000..c828df2c
--- /dev/null
+++ b/bridge/mumble/helpers.go
@@ -0,0 +1,143 @@
+package bmumble
+
+import (
+	"fmt"
+	"mime"
+	"net/http"
+	"regexp"
+	"strings"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/mattn/godown"
+	"github.com/vincent-petithory/dataurl"
+)
+
+type MessagePart struct {
+	Text          string
+	FileExtension string
+	Image         []byte
+}
+
+func (b *Bmumble) decodeImage(uri string, parts *[]MessagePart) error {
+	// Decode the data:image/... URI
+	image, err := dataurl.DecodeString(uri)
+	if err != nil {
+		b.Log.WithError(err).Info("No image extracted")
+		return err
+	}
+	// Determine the file extensions for that image
+	ext, err := mime.ExtensionsByType(image.MediaType.ContentType())
+	if err != nil || len(ext) == 0 {
+		b.Log.WithError(err).Infof("No file extension registered for MIME type '%s'", image.MediaType.ContentType())
+		return err
+	}
+	// Add the image to the MessagePart slice
+	*parts = append(*parts, MessagePart{"", ext[0], image.Data})
+	return nil
+}
+
+func (b *Bmumble) tokenize(t *string) ([]MessagePart, error) {
+	// `^(.*?)` matches everything before the image
+	// `!\[[^\]]*\]\(` matches the `![alt](` part of markdown images
+	// `(data:image\/[^)]+)` matches the data: URI used by Mumble
+	// `\)` matches the closing parenthesis after the URI
+	// `(.*)$` matches the remaining text to be examined in the next iteration
+	p := regexp.MustCompile(`^(?ms)(.*?)!\[[^\]]*\]\((data:image\/[^)]+)\)(.*)$`)
+	remaining := *t
+	var parts []MessagePart
+	for {
+		tokens := p.FindStringSubmatch(remaining)
+		if tokens == nil {
+			// no match -> remaining string is non-image text
+			pre := strings.TrimSpace(remaining)
+			if len(pre) > 0 {
+				parts = append(parts, MessagePart{pre, "", nil})
+			}
+			return parts, nil
+		}
+
+		// tokens[1] is the text before the image
+		if len(tokens[1]) > 0 {
+			pre := strings.TrimSpace(tokens[1])
+			parts = append(parts, MessagePart{pre, "", nil})
+		}
+		// tokens[2] is the image URL
+		uri, err := dataurl.UnescapeToString(strings.TrimSpace(strings.ReplaceAll(tokens[2], " ", "")))
+		if err != nil {
+			b.Log.WithError(err).Info("URL unescaping failed")
+			remaining = strings.TrimSpace(tokens[3])
+			continue
+		}
+		err = b.decodeImage(uri, &parts)
+		if err != nil {
+			b.Log.WithError(err).Info("Decoding the image failed")
+		}
+		// tokens[3] is the text after the image, processed in the next iteration
+		remaining = strings.TrimSpace(tokens[3])
+	}
+}
+
+func (b *Bmumble) convertHTMLtoMarkdown(html string) ([]MessagePart, error) {
+	var sb strings.Builder
+	err := godown.Convert(&sb, strings.NewReader(html), nil)
+	if err != nil {
+		return nil, err
+	}
+	markdown := sb.String()
+	b.Log.Debugf("### to markdown: %s", markdown)
+	return b.tokenize(&markdown)
+}
+
+func (b *Bmumble) extractFiles(msg *config.Message) []config.Message {
+	var messages []config.Message
+	if msg.Extra == nil || len(msg.Extra["file"]) == 0 {
+		return messages
+	}
+	// Create a separate message for each file
+	for _, f := range msg.Extra["file"] {
+		fi := f.(config.FileInfo)
+		imsg := config.Message{
+			Channel:   msg.Channel,
+			Username:  msg.Username,
+			UserID:    msg.UserID,
+			Account:   msg.Account,
+			Protocol:  msg.Protocol,
+			Timestamp: msg.Timestamp,
+			Event:     "mumble_image",
+		}
+		// If no data is present for the file, send a link instead
+		if fi.Data == nil || len(*fi.Data) == 0 {
+			if len(fi.URL) > 0 {
+				imsg.Text = fmt.Sprintf(`<a href="%s">%s</a>`, fi.URL, fi.URL)
+				messages = append(messages, imsg)
+			} else {
+				b.Log.Infof("Not forwarding file without local data")
+			}
+			continue
+		}
+		mimeType := http.DetectContentType(*fi.Data)
+		// Mumble only supports images natively, send a link instead
+		if !strings.HasPrefix(mimeType, "image/") {
+			if len(fi.URL) > 0 {
+				imsg.Text = fmt.Sprintf(`<a href="%s">%s</a>`, fi.URL, fi.URL)
+				messages = append(messages, imsg)
+			} else {
+				b.Log.Infof("Not forwarding file of type %s", mimeType)
+			}
+			continue
+		}
+		mimeType = strings.TrimSpace(strings.Split(mimeType, ";")[0])
+		// Build data:image/...;base64,... style image URL and embed image directly into the message
+		du := dataurl.New(*fi.Data, mimeType)
+		dataURL, err := du.MarshalText()
+		if err != nil {
+			b.Log.WithError(err).Infof("Image Serialization into data URL failed (type: %s, length: %d)", mimeType, len(*fi.Data))
+			continue
+		}
+		imsg.Text = fmt.Sprintf(`<img src="%s"/>`, dataURL)
+		messages = append(messages, imsg)
+	}
+	// Remove files from original message
+	msg.Extra["file"] = nil
+	return messages
+}
diff --git a/bridge/mumble/mumble.go b/bridge/mumble/mumble.go
new file mode 100644
index 00000000..2281d1c2
--- /dev/null
+++ b/bridge/mumble/mumble.go
@@ -0,0 +1,259 @@
+package bmumble
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strconv"
+	"time"
+
+	"layeh.com/gumble/gumble"
+	"layeh.com/gumble/gumbleutil"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	stripmd "github.com/writeas/go-strip-markdown"
+
+	// We need to import the 'data' package as an implicit dependency.
+	// See: https://godoc.org/github.com/paulrosania/go-charset/charset
+	_ "github.com/paulrosania/go-charset/data"
+)
+
+type Bmumble struct {
+	client             *gumble.Client
+	Nick               string
+	Host               string
+	Channel            *uint32
+	local              chan config.Message
+	running            chan error
+	connected          chan gumble.DisconnectEvent
+	serverConfigUpdate chan gumble.ServerConfigEvent
+	serverConfig       gumble.ServerConfigEvent
+	tlsConfig          tls.Config
+
+	*bridge.Config
+}
+
+func New(cfg *bridge.Config) bridge.Bridger {
+	b := &Bmumble{}
+	b.Config = cfg
+	b.Nick = b.GetString("Nick")
+	b.local = make(chan config.Message)
+	b.running = make(chan error)
+	b.connected = make(chan gumble.DisconnectEvent)
+	b.serverConfigUpdate = make(chan gumble.ServerConfigEvent)
+	return b
+}
+
+func (b *Bmumble) Connect() error {
+	b.Log.Infof("Connecting %s", b.GetString("Server"))
+	host, portstr, err := net.SplitHostPort(b.GetString("Server"))
+	if err != nil {
+		return err
+	}
+	b.Host = host
+	_, err = strconv.Atoi(portstr)
+	if err != nil {
+		return err
+	}
+
+	if err = b.buildTLSConfig(); err != nil {
+		return err
+	}
+
+	go b.doSend()
+	go b.connectLoop()
+	err = <-b.running
+	return err
+}
+
+func (b *Bmumble) Disconnect() error {
+	return b.client.Disconnect()
+}
+
+func (b *Bmumble) JoinChannel(channel config.ChannelInfo) error {
+	cid, err := strconv.ParseUint(channel.Name, 10, 32)
+	if err != nil {
+		return err
+	}
+	channelID := uint32(cid)
+	if b.Channel != nil && *b.Channel != channelID {
+		b.Log.Fatalf("Cannot join channel ID '%d', already joined to channel ID %d", channelID, *b.Channel)
+		return errors.New("the Mumble bridge can only join a single channel")
+	}
+	b.Channel = &channelID
+	return b.doJoin(b.client, channelID)
+}
+
+func (b *Bmumble) Send(msg config.Message) (string, error) {
+	// Only process text messages
+	b.Log.Debugf("=> Received local message %#v", msg)
+	if msg.Event != "" && msg.Event != config.EventUserAction {
+		return "", nil
+	}
+
+	attachments := b.extractFiles(&msg)
+	b.local <- msg
+	for _, a := range attachments {
+		b.local <- a
+	}
+	return "", nil
+}
+
+func (b *Bmumble) buildTLSConfig() error {
+	b.tlsConfig = tls.Config{}
+	// Load TLS client certificate keypair required for registered user authentication
+	if cpath := b.GetString("TLSClientCertificate"); cpath != "" {
+		if ckey := b.GetString("TLSClientKey"); ckey != "" {
+			cert, err := tls.LoadX509KeyPair(cpath, ckey)
+			if err != nil {
+				return err
+			}
+			b.tlsConfig.Certificates = []tls.Certificate{cert}
+		}
+	}
+	// Load TLS CA used for server verification.  If not provided, the Go system trust anchor is used
+	if capath := b.GetString("TLSCACertificate"); capath != "" {
+		ca, err := ioutil.ReadFile(capath)
+		if err != nil {
+			return err
+		}
+		b.tlsConfig.RootCAs = x509.NewCertPool()
+		b.tlsConfig.RootCAs.AppendCertsFromPEM(ca)
+	}
+	b.tlsConfig.InsecureSkipVerify = b.GetBool("SkipTLSVerify")
+	return nil
+}
+
+func (b *Bmumble) connectLoop() {
+	firstConnect := true
+	for {
+		err := b.doConnect()
+		if firstConnect {
+			b.running <- err
+		}
+		if err != nil {
+			b.Log.Errorf("Connection to server failed: %#v", err)
+			if firstConnect {
+				break
+			} else {
+				b.Log.Info("Retrying in 10s")
+				time.Sleep(10 * time.Second)
+				continue
+			}
+		}
+		firstConnect = false
+		d := <-b.connected
+		switch d.Type {
+		case gumble.DisconnectError:
+			b.Log.Errorf("Lost connection to the server (%s), attempting reconnect", d.String)
+			continue
+		case gumble.DisconnectKicked:
+			b.Log.Errorf("Kicked from the server (%s), attempting reconnect", d.String)
+			continue
+		case gumble.DisconnectBanned:
+			b.Log.Errorf("Banned from the server (%s), not attempting reconnect", d.String)
+			close(b.connected)
+			close(b.running)
+			return
+		case gumble.DisconnectUser:
+			b.Log.Infof("Disconnect successful")
+			close(b.connected)
+			close(b.running)
+			return
+		}
+	}
+}
+
+func (b *Bmumble) doConnect() error {
+	// Create new gumble config and attach event handlers
+	gumbleConfig := gumble.NewConfig()
+	gumbleConfig.Attach(gumbleutil.Listener{
+		ServerConfig: b.handleServerConfig,
+		TextMessage:  b.handleTextMessage,
+		Connect:      b.handleConnect,
+		Disconnect:   b.handleDisconnect,
+		UserChange:   b.handleUserChange,
+	})
+	gumbleConfig.Username = b.GetString("Nick")
+	if password := b.GetString("Password"); password != "" {
+		gumbleConfig.Password = password
+	}
+
+	client, err := gumble.DialWithDialer(new(net.Dialer), b.GetString("Server"), gumbleConfig, &b.tlsConfig)
+	if err != nil {
+		return err
+	}
+	b.client = client
+	return nil
+}
+
+func (b *Bmumble) doJoin(client *gumble.Client, channelID uint32) error {
+	channel, ok := client.Channels[channelID]
+	if !ok {
+		return fmt.Errorf("no channel with ID %d", channelID)
+	}
+	client.Self.Move(channel)
+	return nil
+}
+
+func (b *Bmumble) doSend() {
+	// Message sending loop that makes sure server-side
+	// restrictions and client-side message traits don't conflict
+	// with each other.
+	for {
+		select {
+		case serverConfig := <-b.serverConfigUpdate:
+			b.Log.Debugf("Received server config update: AllowHTML=%#v, MaximumMessageLength=%#v", serverConfig.AllowHTML, serverConfig.MaximumMessageLength)
+			b.serverConfig = serverConfig
+		case msg := <-b.local:
+			b.processMessage(&msg)
+		}
+	}
+}
+
+func (b *Bmumble) processMessage(msg *config.Message) {
+	b.Log.Debugf("Processing message %s", msg.Text)
+
+	allowHTML := true
+	if b.serverConfig.AllowHTML != nil {
+		allowHTML = *b.serverConfig.AllowHTML
+	}
+
+	// If this is a specially generated image message, send it unmodified
+	if msg.Event == "mumble_image" {
+		if allowHTML {
+			b.client.Self.Channel.Send(msg.Username+msg.Text, false)
+		} else {
+			b.Log.Info("Can't send image, server does not allow HTML messages")
+		}
+		return
+	}
+
+	// Don't process empty messages
+	if len(msg.Text) == 0 {
+		return
+	}
+	// If HTML is allowed, convert markdown into HTML, otherwise strip markdown
+	if allowHTML {
+		msg.Text = helper.ParseMarkdown(msg.Text)
+	} else {
+		msg.Text = stripmd.Strip(msg.Text)
+	}
+
+	// If there is a maximum message length, split and truncate the lines
+	var msgLines []string
+	if maxLength := b.serverConfig.MaximumMessageLength; maxLength != nil {
+		msgLines = helper.GetSubLines(msg.Text, *maxLength-len(msg.Username))
+	} else {
+		msgLines = helper.GetSubLines(msg.Text, 0)
+	}
+	// Send the individual lindes
+	for i := range msgLines {
+		b.client.Self.Channel.Send(msg.Username+msgLines[i], false)
+	}
+}