From e9419f10d3d24e24c9cedab93104c418f383782c Mon Sep 17 00:00:00 2001
From: Duco van Amstel <duco.vanamstel@gmail.com>
Date: Mon, 12 Nov 2018 14:58:00 +0000
Subject: [PATCH] Restore file comments coming from Slack (#583)

---
 bridge/slack/handlers.go | 29 +++++++++--------------------
 bridge/slack/slack.go    | 25 ++++++++++++++++---------
 2 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/bridge/slack/handlers.go b/bridge/slack/handlers.go
index 61f572fa..c4c68961 100644
--- a/bridge/slack/handlers.go
+++ b/bridge/slack/handlers.go
@@ -3,7 +3,6 @@ package bslack
 import (
 	"fmt"
 	"html"
-	"regexp"
 	"time"
 
 	"github.com/42wim/matterbridge/bridge/config"
@@ -228,33 +227,23 @@ func (b *Bslack) handleAttachments(ev *slack.MessageEvent, rmsg *config.Message)
 	}
 
 	// If we have files attached, download them (in memory) and put a pointer to it in msg.Extra.
-	for _, f := range ev.Files {
-		f := f
-		err := b.handleDownloadFile(rmsg, &f)
-		if err != nil {
+	for i := range ev.Files {
+		if err := b.handleDownloadFile(rmsg, &ev.Files[i]); err != nil {
 			b.Log.Errorf("Could not download incoming file: %#v", err)
 		}
 	}
 }
 
-var commentRE = regexp.MustCompile(`.*?commented: (.*)`)
-
 func (b *Bslack) handleTypingEvent(ev *slack.UserTypingEvent) (*config.Message, error) {
-	var err error
-	// use our own func because rtm.GetChannelInfo doesn't work for private channels
 	channelInfo, err := b.getChannelByID(ev.Channel)
 	if err != nil {
 		return nil, err
 	}
-
-	rmsg := config.Message{
+	return &config.Message{
 		Channel: channelInfo.Name,
 		Account: b.Account,
 		Event:   config.EVENT_USER_TYPING,
-	}
-
-	return &rmsg, nil
-
+	}, nil
 }
 
 // handleDownloadFile handles file download
@@ -275,11 +264,11 @@ func (b *Bslack) handleDownloadFile(rmsg *config.Message, file *slack.File) erro
 		return fmt.Errorf("download %s failed %#v", file.URLPrivateDownload, err)
 	}
 
-	// Add the downloaded data to the message.
-	var comment string
-	if results := commentRE.FindAllStringSubmatch(rmsg.Text, -1); len(results) > 0 {
-		comment = results[0][1]
-	}
+	// If a comment is attached to the file(s) it is in the 'Text' field of the Slack messge event
+	// and should be added as comment to only one of the files. We reset the 'Text' field to ensure
+	// that the comment is not duplicated.
+	comment := rmsg.Text
+	rmsg.Text = ""
 	helper.HandleDownloadData(b.Log, rmsg, file.Name, comment, file.URLPrivateDownload, data, b.General)
 	return nil
 }
diff --git a/bridge/slack/slack.go b/bridge/slack/slack.go
index 038e0d90..ecf58287 100644
--- a/bridge/slack/slack.go
+++ b/bridge/slack/slack.go
@@ -207,7 +207,7 @@ func (b *Bslack) Send(msg config.Message) (string, error) {
 
 // sendWebhook uses the configured WebhookURL to send the message
 func (b *Bslack) sendWebhook(msg config.Message) (string, error) {
-	// skip events
+	// Skip events.
 	if msg.Event != "" {
 		return "", nil
 	}
@@ -217,7 +217,7 @@ func (b *Bslack) sendWebhook(msg config.Message) (string, error) {
 	}
 
 	if msg.Extra != nil {
-		// this sends a message only if we received a config.EVENT_FILE_FAILURE_SIZE
+		// This sends a message only if we received a config.EVENT_FILE_FAILURE_SIZE.
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
 			rmsg := rmsg // scopelint
 			iconURL := config.GetIconURL(&rmsg, b.GetString(iconURLConfig))
@@ -232,16 +232,20 @@ func (b *Bslack) sendWebhook(msg config.Message) (string, error) {
 			}
 		}
 
-		// webhook doesn't support file uploads, so we add the url manually
+		// Webhook doesn't support file uploads, so we add the URL manually.
 		for _, f := range msg.Extra["file"] {
-			fi := f.(config.FileInfo)
+			fi, ok := f.(config.FileInfo)
+			if !ok {
+				b.Log.Errorf("Received a file with unexpected content: %#v", f)
+				continue
+			}
 			if fi.URL != "" {
 				msg.Text += " " + fi.URL
 			}
 		}
 	}
 
-	// if we have native slack_attachments add them
+	// If we have native slack_attachments add them.
 	var attachs []slack.Attachment
 	for _, attach := range msg.Extra[sSlackAttachment] {
 		attachs = append(attachs, attach.([]slack.Attachment)...)
@@ -258,9 +262,8 @@ func (b *Bslack) sendWebhook(msg config.Message) (string, error) {
 	if msg.Avatar != "" {
 		matterMessage.IconURL = msg.Avatar
 	}
-	err := b.mh.Send(matterMessage)
-	if err != nil {
-		b.Log.Error(err)
+	if err := b.mh.Send(matterMessage); err != nil {
+		b.Log.Errorf("Failed to send message via webhook: %#v", err)
 		return "", err
 	}
 	return "", nil
@@ -373,7 +376,11 @@ func (b *Bslack) postMessage(msg *config.Message, messageParameters *slack.PostM
 // uploadFile handles native upload of files
 func (b *Bslack) uploadFile(msg *config.Message, channelID string) {
 	for _, f := range msg.Extra["file"] {
-		fi := f.(config.FileInfo)
+		fi, ok := f.(config.FileInfo)
+		if !ok {
+			b.Log.Errorf("Received a file with unexpected content: %#v", f)
+			continue
+		}
 		if msg.Text == fi.Comment {
 			msg.Text = ""
 		}