From c147ba1da1d4d5f181c4de796e414a72248447cc Mon Sep 17 00:00:00 2001
From: Tadeo Kondrak <me@tadeo.ca>
Date: Mon, 15 Feb 2021 14:34:14 -0700
Subject: [PATCH] Handle Rocket.Chat attachments (#1395)

---
 bridge/helper/helper.go       | 24 +++++++++++++++++++++
 bridge/rocketchat/handlers.go | 39 +++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/bridge/helper/helper.go b/bridge/helper/helper.go
index cbb319ac..2d16dc93 100644
--- a/bridge/helper/helper.go
+++ b/bridge/helper/helper.go
@@ -51,6 +51,30 @@ func DownloadFileAuth(url string, auth string) (*[]byte, error) {
 	return &data, nil
 }
 
+// DownloadFileAuthRocket downloads the given URL using the specified Rocket user ID and authentication token.
+func DownloadFileAuthRocket(url, token, userID string) (*[]byte, error) {
+	var buf bytes.Buffer
+	client := &http.Client{
+		Timeout: time.Second * 5,
+	}
+	req, err := http.NewRequest("GET", url, nil)
+
+	req.Header.Add("X-Auth-Token", token)
+	req.Header.Add("X-User-Id", userID)
+
+	if err != nil {
+		return nil, err
+	}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	_, err = io.Copy(&buf, resp.Body)
+	data := buf.Bytes()
+	return &data, err
+}
+
 // GetSubLines splits messages in newline-delimited lines. If maxLineLength is
 // specified as non-zero GetSubLines will also clip long lines to the maximum
 // length and insert a warning marker that the line was clipped.
diff --git a/bridge/rocketchat/handlers.go b/bridge/rocketchat/handlers.go
index 80adb31e..03b66eac 100644
--- a/bridge/rocketchat/handlers.go
+++ b/bridge/rocketchat/handlers.go
@@ -1,7 +1,10 @@
 package brocketchat
 
 import (
+	"fmt"
+
 	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
 	"github.com/matterbridge/Rocket.Chat.Go.SDK/models"
 )
 
@@ -58,6 +61,7 @@ func (b *Brocketchat) handleStatusEvent(ev models.Message, rmsg *config.Message)
 
 func (b *Brocketchat) handleRocketClient(messages chan *config.Message) {
 	for message := range b.messageChan {
+		message := message
 		// skip messages with same ID, apparently messages get duplicated for an unknown reason
 		if _, ok := b.cache.Get(message.ID); ok {
 			continue
@@ -76,8 +80,11 @@ func (b *Brocketchat) handleRocketClient(messages chan *config.Message) {
 			Account:  b.Account,
 			UserID:   message.User.ID,
 			ID:       message.ID,
+			Extra:    make(map[string][]interface{}),
 		}
 
+		b.handleAttachments(&message, rmsg)
+
 		// handleStatusEvent returns false if the message should be dropped
 		// in that case it is probably some modification to the channel we do not want to relay
 		if b.handleStatusEvent(m, rmsg) {
@@ -86,6 +93,38 @@ func (b *Brocketchat) handleRocketClient(messages chan *config.Message) {
 	}
 }
 
+func (b *Brocketchat) handleAttachments(message *models.Message, rmsg *config.Message) {
+	if rmsg.Text == "" {
+		for _, attachment := range message.Attachments {
+			if attachment.Title != "" {
+				rmsg.Text = attachment.Title + "\n"
+			}
+			if attachment.Title != "" && attachment.Text != "" {
+				rmsg.Text += "\n"
+			}
+			if attachment.Text != "" {
+				rmsg.Text += attachment.Text
+			}
+		}
+	}
+
+	for i := range message.Attachments {
+		if err := b.handleDownloadFile(rmsg, &message.Attachments[i]); err != nil {
+			b.Log.Errorf("Could not download incoming file: %#v", err)
+		}
+	}
+}
+
+func (b *Brocketchat) handleDownloadFile(rmsg *config.Message, file *models.Attachment) error {
+	downloadURL := b.GetString("server") + file.TitleLink
+	data, err := helper.DownloadFileAuthRocket(downloadURL, b.user.Token, b.user.ID)
+	if err != nil {
+		return fmt.Errorf("download %s failed %#v", downloadURL, err)
+	}
+	helper.HandleDownloadData(b.Log, rmsg, file.Title, rmsg.Text, downloadURL, data, b.General)
+	return nil
+}
+
 func (b *Brocketchat) handleUploadFile(msg *config.Message) error {
 	for _, f := range msg.Extra["file"] {
 		fi := f.(config.FileInfo)