Refactor slack bridge prelude (#517)

Distributing the source of the Slack bridge across multiple files to
increase readability and as a prelude to various refactors and
clean-ups.

1 files changed, 337 insertions, 0 deletions

diff --git a/bridge/slack/handlers.go b/bridge/slack/handlers.go
new file mode 100644
index 00000000..1ef2d614
--- /dev/null
+++ b/bridge/slack/handlers.go
@@ -0,0 +1,337 @@
+package bslack
+
+import (
+	"bytes"
+	"fmt"
+	"html"
+	"regexp"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/nlopes/slack"
+)
+
+func (b *Bslack) handleSlack() {
+	messages := make(chan *config.Message)
+	if b.GetString("WebhookBindAddress") != "" {
+		b.Log.Debugf("Choosing webhooks based receiving")
+		go b.handleMatterHook(messages)
+	} else {
+		b.Log.Debugf("Choosing token based receiving")
+		go b.handleSlackClient(messages)
+	}
+	time.Sleep(time.Second)
+	b.Log.Debug("Start listening for Slack messages")
+	for message := range messages {
+		b.Log.Debugf("<= Sending message from %s on %s to gateway", message.Username, b.Account)
+
+		// cleanup the message
+		message.Text = b.replaceMention(message.Text)
+		message.Text = b.replaceVariable(message.Text)
+		message.Text = b.replaceChannel(message.Text)
+		message.Text = b.replaceURL(message.Text)
+		message.Text = html.UnescapeString(message.Text)
+
+		// Add the avatar
+		message.Avatar = b.getAvatar(message.UserID)
+
+		b.Log.Debugf("<= Message is %#v", message)
+		b.Remote <- *message
+	}
+}
+
+func (b *Bslack) handleSlackClient(messages chan *config.Message) {
+	for msg := range b.rtm.IncomingEvents {
+		if msg.Type != "user_typing" && msg.Type != "latency_report" {
+			b.Log.Debugf("== Receiving event %#v", msg.Data)
+		}
+		switch ev := msg.Data.(type) {
+		case *slack.MessageEvent:
+			if b.skipMessageEvent(ev) {
+				b.Log.Debugf("Skipped message: %#v", ev)
+				continue
+			}
+			rmsg, err := b.handleMessageEvent(ev)
+			if err != nil {
+				b.Log.Errorf("%#v", err)
+				continue
+			}
+			messages <- rmsg
+		case *slack.OutgoingErrorEvent:
+			b.Log.Debugf("%#v", ev.Error())
+		case *slack.ChannelJoinedEvent:
+			b.Users, _ = b.sc.GetUsers()
+			b.Usergroups, _ = b.sc.GetUserGroups()
+		case *slack.ConnectedEvent:
+			var err error
+			b.channels, _, err = b.sc.GetConversations(&slack.GetConversationsParameters{Limit: 1000, Types: []string{"public_channel,private_channel,mpim,im"}})
+			if err != nil {
+				b.Log.Errorf("Channel list failed: %#v", err)
+			}
+			b.si = ev.Info
+			b.Users, _ = b.sc.GetUsers()
+			b.Usergroups, _ = b.sc.GetUserGroups()
+		case *slack.InvalidAuthEvent:
+			b.Log.Fatalf("Invalid Token %#v", ev)
+		case *slack.ConnectionErrorEvent:
+			b.Log.Errorf("Connection failed %#v %#v", ev.Error(), ev.ErrorObj)
+		default:
+		}
+	}
+}
+
+func (b *Bslack) handleMatterHook(messages chan *config.Message) {
+	for {
+		message := b.mh.Receive()
+		b.Log.Debugf("receiving from matterhook (slack) %#v", message)
+		if message.UserName == "slackbot" {
+			continue
+		}
+		messages <- &config.Message{Username: message.UserName, Text: message.Text, Channel: message.ChannelName}
+	}
+}
+
+// handleDownloadFile handles file download
+func (b *Bslack) handleDownloadFile(rmsg *config.Message, file *slack.File) error {
+	// if we have a file attached, download it (in memory) and put a pointer to it in msg.Extra
+	// limit to 1MB for now
+	comment := ""
+	results := regexp.MustCompile(`.*?commented: (.*)`).FindAllStringSubmatch(rmsg.Text, -1)
+	if len(results) > 0 {
+		comment = results[0][1]
+	}
+	err := helper.HandleDownloadSize(b.Log, rmsg, file.Name, int64(file.Size), b.General)
+	if err != nil {
+		return err
+	}
+	// actually download the file
+	data, err := helper.DownloadFileAuth(file.URLPrivateDownload, "Bearer "+b.GetString("Token"))
+	if err != nil {
+		return fmt.Errorf("download %s failed %#v", file.URLPrivateDownload, err)
+	}
+	// add the downloaded data to the message
+	helper.HandleDownloadData(b.Log, rmsg, file.Name, comment, file.URLPrivateDownload, data, b.General)
+	return nil
+}
+
+// handleUploadFile handles native upload of files
+func (b *Bslack) handleUploadFile(msg *config.Message, channelID string) (string, error) {
+	for _, f := range msg.Extra["file"] {
+		fi := f.(config.FileInfo)
+		if msg.Text == fi.Comment {
+			msg.Text = ""
+		}
+		/* because the result of the UploadFile is slower than the MessageEvent from slack
+		we can't match on the file ID yet, so we have to match on the filename too
+		*/
+		b.Log.Debugf("Adding file %s to cache %s", fi.Name, time.Now().String())
+		b.cache.Add("filename"+fi.Name, time.Now())
+		res, err := b.sc.UploadFile(slack.FileUploadParameters{
+			Reader:         bytes.NewReader(*fi.Data),
+			Filename:       fi.Name,
+			Channels:       []string{channelID},
+			InitialComment: fi.Comment,
+		})
+		if res.ID != "" {
+			b.Log.Debugf("Adding fileid %s to cache %s", res.ID, time.Now().String())
+			b.cache.Add("file"+res.ID, time.Now())
+		}
+		if err != nil {
+			b.Log.Errorf("uploadfile %#v", err)
+		}
+	}
+	return "", nil
+}
+
+// handleMessageEvent handles the message events
+func (b *Bslack) handleMessageEvent(ev *slack.MessageEvent) (*config.Message, error) {
+	// update the userlist on a channel_join
+	if ev.SubType == "channel_join" {
+		b.Users, _ = b.sc.GetUsers()
+	}
+
+	// Edit message
+	if !b.GetBool("EditDisable") && ev.SubMessage != nil && ev.SubMessage.ThreadTimestamp != ev.SubMessage.Timestamp {
+		b.Log.Debugf("SubMessage %#v", ev.SubMessage)
+		ev.User = ev.SubMessage.User
+		ev.Text = ev.SubMessage.Text + b.GetString("EditSuffix")
+	}
+
+	// use our own func because rtm.GetChannelInfo doesn't work for private channels
+	channel, err := b.getChannelByID(ev.Channel)
+	if err != nil {
+		return nil, err
+	}
+
+	rmsg := config.Message{Text: ev.Text, Channel: channel.Name, Account: b.Account, ID: "slack " + ev.Timestamp, Extra: make(map[string][]interface{})}
+
+	if b.UseChannelID {
+		rmsg.Channel = "ID:" + channel.ID
+	}
+
+	// find the user id and name
+	if ev.User != "" && ev.SubType != messageDeleted && ev.SubType != "file_comment" {
+		user, err := b.rtm.GetUserInfo(ev.User)
+		if err != nil {
+			return nil, err
+		}
+		rmsg.UserID = user.ID
+		rmsg.Username = user.Name
+		if user.Profile.DisplayName != "" {
+			rmsg.Username = user.Profile.DisplayName
+		}
+	}
+
+	// See if we have some text in the attachments
+	if rmsg.Text == "" {
+		for _, attach := range ev.Attachments {
+			if attach.Text != "" {
+				if attach.Title != "" {
+					rmsg.Text = attach.Title + "\n"
+				}
+				rmsg.Text += attach.Text
+			} else {
+				rmsg.Text = attach.Fallback
+			}
+		}
+	}
+
+	// when using webhookURL we can't check if it's our webhook or not for now
+	if rmsg.Username == "" && ev.BotID != "" && b.GetString("WebhookURL") == "" {
+		bot, err := b.rtm.GetBotInfo(ev.BotID)
+		if err != nil {
+			return nil, err
+		}
+		if bot.Name != "" {
+			rmsg.Username = bot.Name
+			if ev.Username != "" {
+				rmsg.Username = ev.Username
+			}
+			rmsg.UserID = bot.ID
+		}
+
+		// fixes issues with matterircd users
+		if bot.Name == "Slack API Tester" {
+			user, err := b.rtm.GetUserInfo(ev.User)
+			if err != nil {
+				return nil, err
+			}
+			rmsg.UserID = user.ID
+			rmsg.Username = user.Name
+			if user.Profile.DisplayName != "" {
+				rmsg.Username = user.Profile.DisplayName
+			}
+		}
+	}
+
+	// file comments are set by the system (because there is no username given)
+	if ev.SubType == "file_comment" {
+		rmsg.Username = "system"
+	}
+
+	// do we have a /me action
+	if ev.SubType == "me_message" {
+		rmsg.Event = config.EVENT_USER_ACTION
+	}
+
+	// Handle join/leave
+	if ev.SubType == "channel_leave" || ev.SubType == "channel_join" {
+		rmsg.Username = "system"
+		rmsg.Event = config.EVENT_JOIN_LEAVE
+	}
+
+	// edited messages have a submessage, use this timestamp
+	if ev.SubMessage != nil {
+		rmsg.ID = "slack " + ev.SubMessage.Timestamp
+	}
+
+	// deleted message event
+	if ev.SubType == messageDeleted {
+		rmsg.Text = config.EVENT_MSG_DELETE
+		rmsg.Event = config.EVENT_MSG_DELETE
+		rmsg.ID = "slack " + ev.DeletedTimestamp
+	}
+
+	// topic change event
+	if ev.SubType == "channel_topic" || ev.SubType == "channel_purpose" {
+		rmsg.Event = config.EVENT_TOPIC_CHANGE
+	}
+
+	// Only deleted messages can have a empty username and text
+	if (rmsg.Text == "" || rmsg.Username == "") && ev.SubType != messageDeleted && len(ev.Files) == 0 {
+		// this is probably a webhook we couldn't resolve
+		if ev.BotID != "" {
+			return nil, fmt.Errorf("probably an incoming webhook we couldn't resolve (maybe ourselves)")
+		}
+		return nil, fmt.Errorf("empty message and not a deleted message")
+	}
+
+	// save the attachments, so that we can send them to other slack (compatible) bridges
+	if len(ev.Attachments) > 0 {
+		rmsg.Extra["slack_attachment"] = append(rmsg.Extra["slack_attachment"], ev.Attachments)
+	}
+
+	// if we have a file attached, download it (in memory) and put a pointer to it in msg.Extra
+	if len(ev.Files) > 0 {
+		for _, f := range ev.Files {
+			err := b.handleDownloadFile(&rmsg, &f)
+			if err != nil {
+				b.Log.Errorf("download failed: %s", err)
+			}
+		}
+	}
+
+	return &rmsg, nil
+}
+
+// skipMessageEvent skips event that need to be skipped :-)
+func (b *Bslack) skipMessageEvent(ev *slack.MessageEvent) bool {
+	if ev.SubType == "channel_leave" || ev.SubType == "channel_join" {
+		return b.GetBool("nosendjoinpart")
+	}
+
+	// ignore pinned items
+	if ev.SubType == "pinned_item" || ev.SubType == "unpinned_item" {
+		return true
+	}
+
+	// do not send messages from ourself
+	if b.GetString("WebhookURL") == "" && b.GetString("WebhookBindAddress") == "" && ev.Username == b.si.User.Name {
+		return true
+	}
+
+	// skip messages we made ourselves
+	if len(ev.Attachments) > 0 {
+		if ev.Attachments[0].CallbackID == "matterbridge_"+b.uuid {
+			return true
+		}
+	}
+
+	if !b.GetBool("EditDisable") && ev.SubMessage != nil && ev.SubMessage.ThreadTimestamp != ev.SubMessage.Timestamp {
+		// it seems ev.SubMessage.Edited == nil when slack unfurls
+		// do not forward these messages #266
+		if ev.SubMessage.Edited == nil {
+			return true
+		}
+	}
+
+	if len(ev.Files) > 0 {
+		for _, f := range ev.Files {
+			// if the file is in the cache and isn't older then a minute, skip it
+			if ts, ok := b.cache.Get("file" + f.ID); ok && time.Since(ts.(time.Time)) < time.Minute {
+				b.Log.Debugf("Not downloading file id %s which we uploaded", f.ID)
+				return true
+			} else {
+				if ts, ok := b.cache.Get("filename" + f.Name); ok && time.Since(ts.(time.Time)) < time.Second*10 {
+					b.Log.Debugf("Not downloading file name %s which we uploaded", f.Name)
+					return true
+				} else {
+					b.Log.Debugf("Not skipping %s %s", f.Name, time.Now().String())
+				}
+			}
+		}
+	}
+
+	return false
+}