Add Mumble support (#1245)

1 files changed, 143 insertions, 0 deletions

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
+}