Improve Slack attachments formatting (slack) (#1807)

* Improve Slack attachments formatting (slack)

* Add TitleLink
* Add Footer

* Fix linter issues

bridge/slack/handlers.go

@@ -282,6 +282,13 @@ func (b *Bslack) handleStatusEvent(ev *slack.MessageEvent, rmsg *config.Message)
 	return false
 }
 
+func getMessageTitle(attach *slack.Attachment) string {
+	if attach.TitleLink != "" {
+		return fmt.Sprintf("[%s](%s)\n", attach.Title, attach.TitleLink)
+	}
+	return attach.Title
+}
+
 func (b *Bslack) handleAttachments(ev *slack.MessageEvent, rmsg *config.Message) {
 	// File comments are set by the system (because there is no username given).
 	if ev.SubType == sFileComment {
@@ -290,12 +297,15 @@ func (b *Bslack) handleAttachments(ev *slack.MessageEvent, rmsg *config.Message)
 
 	// See if we have some text in the attachments.
 	if rmsg.Text == "" {
-		for _, attach := range ev.Attachments {
+		for i, attach := range ev.Attachments {
 			if attach.Text != "" {
 				if attach.Title != "" {
-					rmsg.Text = attach.Title + "\n"
+					rmsg.Text = getMessageTitle(&ev.Attachments[i])
 				}
 				rmsg.Text += attach.Text
+				if attach.Footer != "" {
+					rmsg.Text += "\n\n" + attach.Footer
+				}
 			} else {
 				rmsg.Text = attach.Fallback
 			}

bridge/slack/helpers.go

@@ -127,7 +127,7 @@ var (
 	mentionRE        = regexp.MustCompile(`<@([a-zA-Z0-9]+)>`)
 	channelRE        = regexp.MustCompile(`<#[a-zA-Z0-9]+\|(.+?)>`)
 	variableRE       = regexp.MustCompile(`<!((?:subteam\^)?[a-zA-Z0-9]+)(?:\|@?(.+?))?>`)
-	urlRE            = regexp.MustCompile(`<(.*?)(\|.*?)?>`)
+	urlRE            = regexp.MustCompile(`<([^<\|]+)\|([^>]+)>`)
 	codeFenceRE      = regexp.MustCompile(`(?m)^` + "```" + `\w+$`)
 	topicOrPurposeRE = regexp.MustCompile(`(?s)(@.+) (cleared|set)(?: the)? channel (topic|purpose)(?:: (.*))?`)
 )
@@ -181,14 +181,7 @@ func (b *Bslack) replaceVariable(text string) string {
 
 // @see https://api.slack.com/docs/message-formatting#linking_to_urls
 func (b *Bslack) replaceURL(text string) string {
-	for _, r := range urlRE.FindAllStringSubmatch(text, -1) {
-		if len(strings.TrimSpace(r[2])) == 1 { // A display text separator was found, but the text was blank
-			text = strings.Replace(text, r[0], "", 1)
-		} else {
-			text = strings.Replace(text, r[0], r[1], 1)
-		}
-	}
-	return text
+	return urlRE.ReplaceAllString(text, "[${2}](${1})")
 }
 
 func (b *Bslack) replaceb0rkedMarkDown(text string) string {