add matterbridge

6 files changed, 1695 insertions, 0 deletions

diff --git a/teleirc/matterbridge/bridge/slack/handlers.go b/teleirc/matterbridge/bridge/slack/handlers.go
new file mode 100644
index 0000000..2424442
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/handlers.go
@@ -0,0 +1,415 @@
+package bslack
+
+import (
+	"errors"
+	"fmt"
+	"html"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/slack-go/slack"
+)
+
+// ErrEventIgnored is for events that should be ignored
+var ErrEventIgnored = errors.New("this event message should ignored")
+
+func (b *Bslack) handleSlack() {
+	messages := make(chan *config.Message)
+	if b.GetString(incomingWebhookConfig) != "" && b.GetString(tokenConfig) == "" {
+		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 {
+		// don't do any action on deleted/typing messages
+		if message.Event != config.EventUserTyping && message.Event != config.EventMsgDelete &&
+			message.Event != config.EventFileDelete {
+			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 = b.replaceb0rkedMarkDown(message.Text)
+			message.Text = html.UnescapeString(message.Text)
+
+			// Add the avatar
+			message.Avatar = b.users.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 != sUserTyping && msg.Type != sHello && msg.Type != sLatencyReport {
+			b.Log.Debugf("== Receiving event %#v", msg.Data)
+		}
+		switch ev := msg.Data.(type) {
+		case *slack.UserTypingEvent:
+			if !b.GetBool("ShowUserTyping") {
+				continue
+			}
+			rmsg, err := b.handleTypingEvent(ev)
+			if err == ErrEventIgnored {
+				continue
+			} else if err != nil {
+				b.Log.Errorf("%#v", err)
+				continue
+			}
+
+			messages <- rmsg
+		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.FileDeletedEvent:
+			rmsg, err := b.handleFileDeletedEvent(ev)
+			if err != nil {
+				b.Log.Printf("%#v", err)
+				continue
+			}
+			messages <- rmsg
+		case *slack.OutgoingErrorEvent:
+			b.Log.Debugf("%#v", ev.Error())
+		case *slack.ChannelJoinedEvent:
+			// When we join a channel we update the full list of users as
+			// well as the information for the channel that we joined as this
+			// should now tell that we are a member of it.
+			b.channels.registerChannel(ev.Channel)
+		case *slack.ConnectedEvent:
+			b.si = ev.Info
+			b.channels.populateChannels(true)
+			b.users.populateUsers(true)
+		case *slack.InvalidAuthEvent:
+			b.Log.Fatalf("Invalid Token %#v", ev)
+		case *slack.ConnectionErrorEvent:
+			b.Log.Errorf("Connection failed %#v %#v", ev.Error(), ev.ErrorObj)
+		case *slack.MemberJoinedChannelEvent:
+			b.users.populateUser(ev.User)
+		case *slack.HelloEvent, *slack.LatencyReport, *slack.ConnectingEvent:
+			continue
+		case *slack.UserChangeEvent:
+			b.users.invalidateUser(ev.User.ID)
+		default:
+			b.Log.Debugf("Unhandled incoming event: %T", ev)
+		}
+	}
+}
+
+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,
+		}
+	}
+}
+
+// skipMessageEvent skips event that need to be skipped :-)
+func (b *Bslack) skipMessageEvent(ev *slack.MessageEvent) bool {
+	switch ev.SubType {
+	case sChannelLeave, sChannelJoin:
+		return b.GetBool(noSendJoinConfig)
+	case sPinnedItem, sUnpinnedItem:
+		return true
+	case sChannelTopic, sChannelPurpose:
+		// Skip the event if our bot/user account changed the topic/purpose
+		if ev.User == b.si.User.ID {
+			return true
+		}
+	}
+
+	// Check for our callback ID
+	hasOurCallbackID := false
+	if len(ev.Blocks.BlockSet) == 1 {
+		block, ok := ev.Blocks.BlockSet[0].(*slack.SectionBlock)
+		hasOurCallbackID = ok && block.BlockID == "matterbridge_"+b.uuid
+	}
+
+	if ev.SubMessage != nil {
+		// It seems ev.SubMessage.Edited == nil when slack unfurls.
+		// Do not forward these messages. See Github issue #266.
+		if ev.SubMessage.ThreadTimestamp != ev.SubMessage.Timestamp &&
+			ev.SubMessage.Edited == nil {
+			return true
+		}
+		// see hidden subtypes at https://api.slack.com/events/message
+		// these messages are sent when we add a message to a thread #709
+		if ev.SubType == "message_replied" && ev.Hidden {
+			return true
+		}
+		if len(ev.SubMessage.Blocks.BlockSet) == 1 {
+			block, ok := ev.SubMessage.Blocks.BlockSet[0].(*slack.SectionBlock)
+			hasOurCallbackID = ok && block.BlockID == "matterbridge_"+b.uuid
+		}
+	}
+
+	// Skip any messages that we made ourselves or from 'slackbot' (see #527).
+	if ev.Username == sSlackBotUser ||
+		(b.rtm != nil && ev.Username == b.si.User.Name) || hasOurCallbackID {
+		return true
+	}
+
+	if len(ev.Files) > 0 {
+		return b.filesCached(ev.Files)
+	}
+	return false
+}
+
+func (b *Bslack) filesCached(files []slack.File) bool {
+	for i := range files {
+		if !b.fileCached(&files[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+// handleMessageEvent handles the message events. Together with any called sub-methods,
+// this method implements the following event processing pipeline:
+//
+// 1. Check if the message should be ignored.
+//    NOTE: This is not actually part of the method below but is done just before it
+//          is called via the 'skipMessageEvent()' method.
+// 2. Populate the Matterbridge message that will be sent to the router based on the
+//    received event and logic that is common to all events that are not skipped.
+// 3. Detect and handle any message that is "status" related (think join channel, etc.).
+//    This might result in an early exit from the pipeline and passing of the
+//    pre-populated message to the Matterbridge router.
+// 4. Handle the specific case of messages that edit existing messages depending on
+//    configuration.
+// 5. Handle any attachments of the received event.
+// 6. Check that the Matterbridge message that we end up with after at the end of the
+//    pipeline is valid before sending it to the Matterbridge router.
+func (b *Bslack) handleMessageEvent(ev *slack.MessageEvent) (*config.Message, error) {
+	rmsg, err := b.populateReceivedMessage(ev)
+	if err != nil {
+		return nil, err
+	}
+
+	// Handle some message types early.
+	if b.handleStatusEvent(ev, rmsg) {
+		return rmsg, nil
+	}
+
+	b.handleAttachments(ev, rmsg)
+
+	// Verify that we have the right information and the message
+	// is well-formed before sending it out to the router.
+	if len(ev.Files) == 0 && (rmsg.Text == "" || rmsg.Username == "") {
+		if ev.BotID != "" {
+			// This is probably a webhook we couldn't resolve.
+			return nil, fmt.Errorf("message handling resulted in an empty bot message (probably an incoming webhook we couldn't resolve): %#v", ev)
+		}
+		if ev.SubMessage != nil {
+			return nil, fmt.Errorf("message handling resulted in an empty message: %#v with submessage %#v", ev, ev.SubMessage)
+		}
+		return nil, fmt.Errorf("message handling resulted in an empty message: %#v", ev)
+	}
+	return rmsg, nil
+}
+
+func (b *Bslack) handleFileDeletedEvent(ev *slack.FileDeletedEvent) (*config.Message, error) {
+	if rawChannel, ok := b.cache.Get(cfileDownloadChannel + ev.FileID); ok {
+		channel, err := b.channels.getChannelByID(rawChannel.(string))
+		if err != nil {
+			return nil, err
+		}
+
+		return &config.Message{
+			Event:    config.EventFileDelete,
+			Text:     config.EventFileDelete,
+			Channel:  channel.Name,
+			Account:  b.Account,
+			ID:       ev.FileID,
+			Protocol: b.Protocol,
+		}, nil
+	}
+
+	return nil, fmt.Errorf("channel ID for file ID %s not found", ev.FileID)
+}
+
+func (b *Bslack) handleStatusEvent(ev *slack.MessageEvent, rmsg *config.Message) bool {
+	switch ev.SubType {
+	case sChannelJoined, sMemberJoined:
+		// There's no further processing needed on channel events
+		// so we return 'true'.
+		return true
+	case sChannelJoin, sChannelLeave:
+		rmsg.Username = sSystemUser
+		rmsg.Event = config.EventJoinLeave
+	case sChannelTopic, sChannelPurpose:
+		b.channels.populateChannels(false)
+		rmsg.Event = config.EventTopicChange
+	case sMessageChanged:
+		rmsg.Text = ev.SubMessage.Text
+		// handle deleted thread starting messages
+		if ev.SubMessage.Text == "This message was deleted." {
+			rmsg.Event = config.EventMsgDelete
+			return true
+		}
+	case sMessageDeleted:
+		rmsg.Text = config.EventMsgDelete
+		rmsg.Event = config.EventMsgDelete
+		rmsg.ID = ev.DeletedTimestamp
+		// If a message is being deleted we do not need to process
+		// the event any further so we return 'true'.
+		return true
+	case sMeMessage:
+		rmsg.Event = config.EventUserAction
+	}
+	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 {
+		rmsg.Username = sSystemUser
+	}
+
+	// See if we have some text in the attachments.
+	if rmsg.Text == "" {
+		for i, attach := range ev.Attachments {
+			if attach.Text != "" {
+				if attach.Title != "" {
+					rmsg.Text = getMessageTitle(&ev.Attachments[i])
+				}
+				rmsg.Text += attach.Text
+				if attach.Footer != "" {
+					rmsg.Text += "\n\n" + attach.Footer
+				}
+			} else {
+				rmsg.Text = attach.Fallback
+			}
+		}
+	}
+
+	// Save the attachments, so that we can send them to other slack (compatible) bridges.
+	if len(ev.Attachments) > 0 {
+		rmsg.Extra[sSlackAttachment] = append(rmsg.Extra[sSlackAttachment], ev.Attachments)
+	}
+
+	// If we have files attached, download them (in memory) and put a pointer to it in msg.Extra.
+	for i := range ev.Files {
+		// keep reference in cache on which channel we added this file
+		b.cache.Add(cfileDownloadChannel+ev.Files[i].ID, ev.Channel)
+		if err := b.handleDownloadFile(rmsg, &ev.Files[i], false); err != nil {
+			b.Log.Errorf("Could not download incoming file: %#v", err)
+		}
+	}
+}
+
+func (b *Bslack) handleTypingEvent(ev *slack.UserTypingEvent) (*config.Message, error) {
+	if ev.User == b.si.User.ID {
+		return nil, ErrEventIgnored
+	}
+	channelInfo, err := b.channels.getChannelByID(ev.Channel)
+	if err != nil {
+		return nil, err
+	}
+	return &config.Message{
+		Channel: channelInfo.Name,
+		Account: b.Account,
+		Event:   config.EventUserTyping,
+	}, nil
+}
+
+// handleDownloadFile handles file download
+func (b *Bslack) handleDownloadFile(rmsg *config.Message, file *slack.File, retry bool) error {
+	if b.fileCached(file) {
+		return nil
+	}
+	// Check that the file is neither too large nor blacklisted.
+	if err := helper.HandleDownloadSize(b.Log, rmsg, file.Name, int64(file.Size), b.General); err != nil {
+		b.Log.WithError(err).Infof("Skipping download of incoming file.")
+		return nil
+	}
+
+	// Actually download the file.
+	data, err := helper.DownloadFileAuth(file.URLPrivateDownload, "Bearer "+b.GetString(tokenConfig))
+	if err != nil {
+		return fmt.Errorf("download %s failed %#v", file.URLPrivateDownload, err)
+	}
+
+	if len(*data) != file.Size && !retry {
+		b.Log.Debugf("Data size (%d) is not equal to size declared (%d)\n", len(*data), file.Size)
+		time.Sleep(1 * time.Second)
+		return b.handleDownloadFile(rmsg, file, true)
+	}
+
+	// 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.HandleDownloadData2(b.Log, rmsg, file.Name, file.ID, comment, file.URLPrivateDownload, data, b.General)
+	return nil
+}
+
+// handleGetChannelMembers handles messages containing the GetChannelMembers event
+// Sends a message to the router containing *config.ChannelMembers
+func (b *Bslack) handleGetChannelMembers(rmsg *config.Message) bool {
+	if rmsg.Event != config.EventGetChannelMembers {
+		return false
+	}
+
+	cMembers := b.channels.getChannelMembers(b.users)
+
+	extra := make(map[string][]interface{})
+	extra[config.EventGetChannelMembers] = append(extra[config.EventGetChannelMembers], cMembers)
+	msg := config.Message{
+		Extra:   extra,
+		Event:   config.EventGetChannelMembers,
+		Account: b.Account,
+	}
+
+	b.Log.Debugf("sending msg to remote %#v", msg)
+	b.Remote <- msg
+
+	return true
+}
+
+// fileCached implements Matterbridge's caching logic for files
+// shared via Slack.
+//
+// We consider that a file was cached if its ID was added in the last minute or
+// it's name was registered in the last 10 seconds. This ensures that an
+// identically named file but with different content will be uploaded correctly
+// (the assumption is that such name collisions will not occur within the given
+// timeframes).
+func (b *Bslack) fileCached(file *slack.File) bool {
+	if ts, ok := b.cache.Get("file" + file.ID); ok && time.Since(ts.(time.Time)) < time.Minute {
+		return true
+	} else if ts, ok = b.cache.Get("filename" + file.Name); ok && time.Since(ts.(time.Time)) < 10*time.Second {
+		return true
+	}
+	return false
+}
diff --git a/teleirc/matterbridge/bridge/slack/helpers.go b/teleirc/matterbridge/bridge/slack/helpers.go
new file mode 100644
index 0000000..e46e272
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/helpers.go
@@ -0,0 +1,255 @@
+package bslack
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/sirupsen/logrus"
+	"github.com/slack-go/slack"
+)
+
+// populateReceivedMessage shapes the initial Matterbridge message that we will forward to the
+// router before we apply message-dependent modifications.
+func (b *Bslack) populateReceivedMessage(ev *slack.MessageEvent) (*config.Message, error) {
+	// Use our own func because rtm.GetChannelInfo doesn't work for private channels.
+	channel, err := b.channels.getChannelByID(ev.Channel)
+	if err != nil {
+		return nil, err
+	}
+
+	rmsg := &config.Message{
+		Text:     ev.Text,
+		Channel:  channel.Name,
+		Account:  b.Account,
+		ID:       ev.Timestamp,
+		Extra:    make(map[string][]interface{}),
+		ParentID: ev.ThreadTimestamp,
+		Protocol: b.Protocol,
+	}
+	if b.useChannelID {
+		rmsg.Channel = "ID:" + channel.ID
+	}
+
+	// Handle 'edit' messages.
+	if ev.SubMessage != nil && !b.GetBool(editDisableConfig) {
+		rmsg.ID = ev.SubMessage.Timestamp
+		if ev.SubMessage.ThreadTimestamp != ev.SubMessage.Timestamp {
+			b.Log.Debugf("SubMessage %#v", ev.SubMessage)
+			rmsg.Text = ev.SubMessage.Text + b.GetString(editSuffixConfig)
+		}
+	}
+
+	// For edits, only submessage has thread ts.
+	// Ensures edits to threaded messages maintain their prefix hint on the
+	// unthreaded end.
+	if ev.SubMessage != nil {
+		rmsg.ParentID = ev.SubMessage.ThreadTimestamp
+	}
+
+	if err = b.populateMessageWithUserInfo(ev, rmsg); err != nil {
+		return nil, err
+	}
+	return rmsg, err
+}
+
+func (b *Bslack) populateMessageWithUserInfo(ev *slack.MessageEvent, rmsg *config.Message) error {
+	if ev.SubType == sMessageDeleted || ev.SubType == sFileComment {
+		return nil
+	}
+
+	// First, deal with bot-originating messages but only do so when not using webhooks: we
+	// would not be able to distinguish which bot would be sending them.
+	if err := b.populateMessageWithBotInfo(ev, rmsg); err != nil {
+		return err
+	}
+
+	// Second, deal with "real" users if we have the necessary information.
+	var userID string
+	switch {
+	case ev.User != "":
+		userID = ev.User
+	case ev.SubMessage != nil && ev.SubMessage.User != "":
+		userID = ev.SubMessage.User
+	default:
+		return nil
+	}
+
+	user := b.users.getUser(userID)
+	if user == nil {
+		return fmt.Errorf("could not find information for user with id %s", ev.User)
+	}
+
+	rmsg.UserID = user.ID
+	rmsg.Username = user.Name
+	if user.Profile.DisplayName != "" {
+		rmsg.Username = user.Profile.DisplayName
+	}
+	if b.GetBool("UseFullName") && user.Profile.RealName != "" {
+		rmsg.Username = user.Profile.RealName
+	}
+	return nil
+}
+
+func (b *Bslack) populateMessageWithBotInfo(ev *slack.MessageEvent, rmsg *config.Message) error {
+	if ev.BotID == "" || b.GetString(outgoingWebhookConfig) != "" {
+		return nil
+	}
+
+	var err error
+	var bot *slack.Bot
+	for {
+		bot, err = b.rtm.GetBotInfo(ev.BotID)
+		if err == nil {
+			break
+		}
+
+		if err = handleRateLimit(b.Log, err); err != nil {
+			b.Log.Errorf("Could not retrieve bot information: %#v", err)
+			return err
+		}
+	}
+	b.Log.Debugf("Found bot %#v", bot)
+
+	if bot.Name != "" {
+		rmsg.Username = bot.Name
+		if ev.Username != "" {
+			rmsg.Username = ev.Username
+		}
+		rmsg.UserID = bot.ID
+	}
+	return nil
+}
+
+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(`<([^<\|]+)\|([^>]+)>`)
+	codeFenceRE      = regexp.MustCompile(`(?m)^` + "```" + `\w+$`)
+	topicOrPurposeRE = regexp.MustCompile(`(?s)(@.+) (cleared|set)(?: the)? channel (topic|purpose)(?:: (.*))?`)
+)
+
+func (b *Bslack) extractTopicOrPurpose(text string) (string, string) {
+	r := topicOrPurposeRE.FindStringSubmatch(text)
+	if len(r) == 5 {
+		action, updateType, extracted := r[2], r[3], r[4]
+		switch action {
+		case "set":
+			return updateType, extracted
+		case "cleared":
+			return updateType, ""
+		}
+	}
+	b.Log.Warnf("Encountered channel topic or purpose change message with unexpected format: %s", text)
+	return "unknown", ""
+}
+
+// @see https://api.slack.com/docs/message-formatting#linking_to_channels_and_users
+func (b *Bslack) replaceMention(text string) string {
+	replaceFunc := func(match string) string {
+		userID := strings.Trim(match, "@<>")
+		if username := b.users.getUsername(userID); userID != "" {
+			return "@" + username
+		}
+		return match
+	}
+	return mentionRE.ReplaceAllStringFunc(text, replaceFunc)
+}
+
+// @see https://api.slack.com/docs/message-formatting#linking_to_channels_and_users
+func (b *Bslack) replaceChannel(text string) string {
+	for _, r := range channelRE.FindAllStringSubmatch(text, -1) {
+		text = strings.Replace(text, r[0], "#"+r[1], 1)
+	}
+	return text
+}
+
+// @see https://api.slack.com/docs/message-formatting#variables
+func (b *Bslack) replaceVariable(text string) string {
+	for _, r := range variableRE.FindAllStringSubmatch(text, -1) {
+		if r[2] != "" {
+			text = strings.Replace(text, r[0], "@"+r[2], 1)
+		} else {
+			text = strings.Replace(text, r[0], "@"+r[1], 1)
+		}
+	}
+	return text
+}
+
+// @see https://api.slack.com/docs/message-formatting#linking_to_urls
+func (b *Bslack) replaceURL(text string) string {
+	return urlRE.ReplaceAllString(text, "[${2}](${1})")
+}
+
+func (b *Bslack) replaceb0rkedMarkDown(text string) string {
+	// taken from https://github.com/mattermost/mattermost-server/blob/master/app/slackimport.go
+	//
+	regexReplaceAllString := []struct {
+		regex *regexp.Regexp
+		rpl   string
+	}{
+		// bold
+		{
+			regexp.MustCompile(`(^|[\s.;,])\*(\S[^*\n]+)\*`),
+			"$1**$2**",
+		},
+		// strikethrough
+		{
+			regexp.MustCompile(`(^|[\s.;,])\~(\S[^~\n]+)\~`),
+			"$1~~$2~~",
+		},
+		// single paragraph blockquote
+		// Slack converts > character to &gt;
+		{
+			regexp.MustCompile(`(?sm)^&gt;`),
+			">",
+		},
+	}
+	for _, rule := range regexReplaceAllString {
+		text = rule.regex.ReplaceAllString(text, rule.rpl)
+	}
+	return text
+}
+
+func (b *Bslack) replaceCodeFence(text string) string {
+	return codeFenceRE.ReplaceAllString(text, "```")
+}
+
+// getUsersInConversation returns an array of userIDs that are members of channelID
+func (b *Bslack) getUsersInConversation(channelID string) ([]string, error) {
+	channelMembers := []string{}
+	for {
+		queryParams := &slack.GetUsersInConversationParameters{
+			ChannelID: channelID,
+		}
+
+		members, nextCursor, err := b.sc.GetUsersInConversation(queryParams)
+		if err != nil {
+			if err = handleRateLimit(b.Log, err); err != nil {
+				return channelMembers, fmt.Errorf("Could not retrieve users in channels: %#v", err)
+			}
+			continue
+		}
+
+		channelMembers = append(channelMembers, members...)
+
+		if nextCursor == "" {
+			break
+		}
+		queryParams.Cursor = nextCursor
+	}
+	return channelMembers, nil
+}
+
+func handleRateLimit(log *logrus.Entry, err error) error {
+	rateLimit, ok := err.(*slack.RateLimitedError)
+	if !ok {
+		return err
+	}
+	log.Infof("Rate-limited by Slack. Sleeping for %v", rateLimit.RetryAfter)
+	time.Sleep(rateLimit.RetryAfter)
+	return nil
+}
diff --git a/teleirc/matterbridge/bridge/slack/helpers_test.go b/teleirc/matterbridge/bridge/slack/helpers_test.go
new file mode 100644
index 0000000..fe3ba41
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/helpers_test.go
@@ -0,0 +1,36 @@
+package bslack
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExtractTopicOrPurpose(t *testing.T) {
+	testcases := map[string]struct {
+		input          string
+		wantChangeType string
+		wantOutput     string
+	}{
+		"success - topic type":   {"@someone set channel topic: foo bar", "topic", "foo bar"},
+		"success - purpose type": {"@someone set channel purpose: foo bar", "purpose", "foo bar"},
+		"success - one line":     {"@someone set channel topic: foo bar", "topic", "foo bar"},
+		"success - multi-line":   {"@someone set channel topic: foo\nbar", "topic", "foo\nbar"},
+		"success - cleared":      {"@someone cleared channel topic", "topic", ""},
+		"error - unhandled":      {"some unmatched message", "unknown", ""},
+	}
+
+	logger := logrus.New()
+	logger.SetOutput(ioutil.Discard)
+	cfg := &bridge.Config{Bridge: &bridge.Bridge{Log: logrus.NewEntry(logger)}}
+	b := newBridge(cfg)
+	for name, tc := range testcases {
+		gotChangeType, gotOutput := b.extractTopicOrPurpose(tc.input)
+
+		assert.Equalf(t, tc.wantChangeType, gotChangeType, "This testcase failed: %s", name)
+		assert.Equalf(t, tc.wantOutput, gotOutput, "This testcase failed: %s", name)
+	}
+}
diff --git a/teleirc/matterbridge/bridge/slack/legacy.go b/teleirc/matterbridge/bridge/slack/legacy.go
new file mode 100644
index 0000000..d89d286
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/legacy.go
@@ -0,0 +1,80 @@
+package bslack
+
+import (
+	"errors"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/matterhook"
+	"github.com/slack-go/slack"
+)
+
+type BLegacy struct {
+	*Bslack
+}
+
+func NewLegacy(cfg *bridge.Config) bridge.Bridger {
+	b := &BLegacy{Bslack: newBridge(cfg)}
+	b.legacy = true
+	return b
+}
+
+func (b *BLegacy) Connect() error {
+	b.RLock()
+	defer b.RUnlock()
+	if b.GetString(incomingWebhookConfig) != "" {
+		switch {
+		case b.GetString(outgoingWebhookConfig) != "":
+			b.Log.Info("Connecting using webhookurl (sending) and webhookbindaddress (receiving)")
+			b.mh = matterhook.New(b.GetString(outgoingWebhookConfig), matterhook.Config{
+				InsecureSkipVerify: b.GetBool(skipTLSConfig),
+				BindAddress:        b.GetString(incomingWebhookConfig),
+			})
+		case b.GetString(tokenConfig) != "":
+			b.Log.Info("Connecting using token (sending)")
+			b.sc = slack.New(b.GetString(tokenConfig))
+			b.rtm = b.sc.NewRTM()
+			go b.rtm.ManageConnection()
+			b.Log.Info("Connecting using webhookbindaddress (receiving)")
+			b.mh = matterhook.New(b.GetString(outgoingWebhookConfig), matterhook.Config{
+				InsecureSkipVerify: b.GetBool(skipTLSConfig),
+				BindAddress:        b.GetString(incomingWebhookConfig),
+			})
+		default:
+			b.Log.Info("Connecting using webhookbindaddress (receiving)")
+			b.mh = matterhook.New(b.GetString(outgoingWebhookConfig), matterhook.Config{
+				InsecureSkipVerify: b.GetBool(skipTLSConfig),
+				BindAddress:        b.GetString(incomingWebhookConfig),
+			})
+		}
+		go b.handleSlack()
+		return nil
+	}
+	if b.GetString(outgoingWebhookConfig) != "" {
+		b.Log.Info("Connecting using webhookurl (sending)")
+		b.mh = matterhook.New(b.GetString(outgoingWebhookConfig), matterhook.Config{
+			InsecureSkipVerify: b.GetBool(skipTLSConfig),
+			DisableServer:      true,
+		})
+		if b.GetString(tokenConfig) != "" {
+			b.Log.Info("Connecting using token (receiving)")
+			b.sc = slack.New(b.GetString(tokenConfig), slack.OptionDebug(b.GetBool("debug")))
+			b.channels = newChannelManager(b.Log, b.sc)
+			b.users = newUserManager(b.Log, b.sc)
+			b.rtm = b.sc.NewRTM()
+			go b.rtm.ManageConnection()
+			go b.handleSlack()
+		}
+	} else if b.GetString(tokenConfig) != "" {
+		b.Log.Info("Connecting using token (sending and receiving)")
+		b.sc = slack.New(b.GetString(tokenConfig), slack.OptionDebug(b.GetBool("debug")))
+		b.channels = newChannelManager(b.Log, b.sc)
+		b.users = newUserManager(b.Log, b.sc)
+		b.rtm = b.sc.NewRTM()
+		go b.rtm.ManageConnection()
+		go b.handleSlack()
+	}
+	if b.GetString(incomingWebhookConfig) == "" && b.GetString(outgoingWebhookConfig) == "" && b.GetString(tokenConfig) == "" {
+		return errors.New("no connection method found. See that you have WebhookBindAddress, WebhookURL or Token configured")
+	}
+	return nil
+}
diff --git a/teleirc/matterbridge/bridge/slack/slack.go b/teleirc/matterbridge/bridge/slack/slack.go
new file mode 100644
index 0000000..c39c608
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/slack.go
@@ -0,0 +1,566 @@
+package bslack
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge"
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/42wim/matterbridge/bridge/helper"
+	"github.com/42wim/matterbridge/matterhook"
+	lru "github.com/hashicorp/golang-lru"
+	"github.com/rs/xid"
+	"github.com/slack-go/slack"
+)
+
+type Bslack struct {
+	sync.RWMutex
+	*bridge.Config
+
+	mh  *matterhook.Client
+	sc  *slack.Client
+	rtm *slack.RTM
+	si  *slack.Info
+
+	cache        *lru.Cache
+	uuid         string
+	useChannelID bool
+
+	channels *channels
+	users    *users
+	legacy   bool
+}
+
+const (
+	sHello               = "hello"
+	sChannelJoin         = "channel_join"
+	sChannelLeave        = "channel_leave"
+	sChannelJoined       = "channel_joined"
+	sMemberJoined        = "member_joined_channel"
+	sMessageChanged      = "message_changed"
+	sMessageDeleted      = "message_deleted"
+	sSlackAttachment     = "slack_attachment"
+	sPinnedItem          = "pinned_item"
+	sUnpinnedItem        = "unpinned_item"
+	sChannelTopic        = "channel_topic"
+	sChannelPurpose      = "channel_purpose"
+	sFileComment         = "file_comment"
+	sMeMessage           = "me_message"
+	sUserTyping          = "user_typing"
+	sLatencyReport       = "latency_report"
+	sSystemUser          = "system"
+	sSlackBotUser        = "slackbot"
+	cfileDownloadChannel = "file_download_channel"
+
+	tokenConfig           = "Token"
+	incomingWebhookConfig = "WebhookBindAddress"
+	outgoingWebhookConfig = "WebhookURL"
+	skipTLSConfig         = "SkipTLSVerify"
+	useNickPrefixConfig   = "PrefixMessagesWithNick"
+	editDisableConfig     = "EditDisable"
+	editSuffixConfig      = "EditSuffix"
+	iconURLConfig         = "iconurl"
+	noSendJoinConfig      = "nosendjoinpart"
+	messageLength         = 3000
+)
+
+func New(cfg *bridge.Config) bridge.Bridger {
+	// Print a deprecation warning for legacy non-bot tokens (#527).
+	token := cfg.GetString(tokenConfig)
+	if token != "" && !strings.HasPrefix(token, "xoxb") {
+		cfg.Log.Warn("Non-bot token detected. It is STRONGLY recommended to use a proper bot-token instead.")
+		cfg.Log.Warn("Legacy tokens may be deprecated by Slack at short notice. See the Matterbridge GitHub wiki for a migration guide.")
+		cfg.Log.Warn("See https://github.com/42wim/matterbridge/wiki/Slack-bot-setup")
+		return NewLegacy(cfg)
+	}
+	return newBridge(cfg)
+}
+
+func newBridge(cfg *bridge.Config) *Bslack {
+	newCache, err := lru.New(5000)
+	if err != nil {
+		cfg.Log.Fatalf("Could not create LRU cache for Slack bridge: %v", err)
+	}
+	b := &Bslack{
+		Config: cfg,
+		uuid:   xid.New().String(),
+		cache:  newCache,
+	}
+	return b
+}
+
+func (b *Bslack) Command(cmd string) string {
+	return ""
+}
+
+func (b *Bslack) Connect() error {
+	b.RLock()
+	defer b.RUnlock()
+
+	if b.GetString(incomingWebhookConfig) == "" && b.GetString(outgoingWebhookConfig) == "" && b.GetString(tokenConfig) == "" {
+		return errors.New("no connection method found: WebhookBindAddress, WebhookURL or Token need to be configured")
+	}
+
+	// If we have a token we use the Slack websocket-based RTM for both sending and receiving.
+	if token := b.GetString(tokenConfig); token != "" {
+		b.Log.Info("Connecting using token")
+
+		b.sc = slack.New(token, slack.OptionDebug(b.GetBool("Debug")))
+
+		b.channels = newChannelManager(b.Log, b.sc)
+		b.users = newUserManager(b.Log, b.sc)
+
+		b.rtm = b.sc.NewRTM()
+		go b.rtm.ManageConnection()
+		go b.handleSlack()
+		return nil
+	}
+
+	// In absence of a token we fall back to incoming and outgoing Webhooks.
+	b.mh = matterhook.New(
+		"",
+		matterhook.Config{
+			InsecureSkipVerify: b.GetBool("SkipTLSVerify"),
+			DisableServer:      true,
+		},
+	)
+	if b.GetString(outgoingWebhookConfig) != "" {
+		b.Log.Info("Using specified webhook for outgoing messages.")
+		b.mh.Url = b.GetString(outgoingWebhookConfig)
+	}
+	if b.GetString(incomingWebhookConfig) != "" {
+		b.Log.Info("Setting up local webhook for incoming messages.")
+		b.mh.BindAddress = b.GetString(incomingWebhookConfig)
+		b.mh.DisableServer = false
+		go b.handleSlack()
+	}
+	return nil
+}
+
+func (b *Bslack) Disconnect() error {
+	return b.rtm.Disconnect()
+}
+
+// JoinChannel only acts as a verification method that checks whether Matterbridge's
+// Slack integration is already member of the channel. This is because Slack does not
+// allow apps or bots to join channels themselves and they need to be invited
+// manually by a user.
+func (b *Bslack) JoinChannel(channel config.ChannelInfo) error {
+	// We can only join a channel through the Slack API.
+	if b.sc == nil {
+		return nil
+	}
+
+	// try to join a channel when in legacy
+	if b.legacy {
+		_, _, _, err := b.sc.JoinConversation(channel.Name)
+		if err != nil {
+			switch err.Error() {
+			case "name_taken", "restricted_action":
+			case "default":
+				return err
+			}
+		}
+	}
+
+	b.channels.populateChannels(false)
+
+	channelInfo, err := b.channels.getChannel(channel.Name)
+	if err != nil {
+		return fmt.Errorf("could not join channel: %#v", err)
+	}
+
+	if strings.HasPrefix(channel.Name, "ID:") {
+		b.useChannelID = true
+		channel.Name = channelInfo.Name
+	}
+
+	// we can't join a channel unless we are using legacy tokens #651
+	if !channelInfo.IsMember && !b.legacy {
+		return fmt.Errorf("slack integration that matterbridge is using is not member of channel '%s', please add it manually", channelInfo.Name)
+	}
+	return nil
+}
+
+func (b *Bslack) Reload(cfg *bridge.Config) (string, error) {
+	return "", nil
+}
+
+func (b *Bslack) Send(msg config.Message) (string, error) {
+	// Too noisy to log like other events
+	if msg.Event != config.EventUserTyping {
+		b.Log.Debugf("=> Receiving %#v", msg)
+	}
+
+	msg.Text = helper.ClipMessage(msg.Text, messageLength, b.GetString("MessageClipped"))
+	msg.Text = b.replaceCodeFence(msg.Text)
+
+	// Make a action /me of the message
+	if msg.Event == config.EventUserAction {
+		msg.Text = "_" + msg.Text + "_"
+	}
+
+	// Use webhook to send the message
+	if b.GetString(outgoingWebhookConfig) != "" && b.GetString(tokenConfig) == "" {
+		return "", b.sendWebhook(msg)
+	}
+	return b.sendRTM(msg)
+}
+
+// sendWebhook uses the configured WebhookURL to send the message
+func (b *Bslack) sendWebhook(msg config.Message) error {
+	// Skip events.
+	if msg.Event != "" {
+		return nil
+	}
+
+	if b.GetBool(useNickPrefixConfig) {
+		msg.Text = msg.Username + msg.Text
+	}
+
+	if msg.Extra != nil {
+		// 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))
+			matterMessage := matterhook.OMessage{
+				IconURL:  iconURL,
+				Channel:  msg.Channel,
+				UserName: rmsg.Username,
+				Text:     rmsg.Text,
+			}
+			if err := b.mh.Send(matterMessage); err != nil {
+				b.Log.Errorf("Failed to send message: %v", err)
+			}
+		}
+
+		// Webhook doesn't support file uploads, so we add the URL manually.
+		for _, f := range msg.Extra["file"] {
+			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.
+	var attachs []slack.Attachment
+	for _, attach := range msg.Extra[sSlackAttachment] {
+		attachs = append(attachs, attach.([]slack.Attachment)...)
+	}
+
+	iconURL := config.GetIconURL(&msg, b.GetString(iconURLConfig))
+	matterMessage := matterhook.OMessage{
+		IconURL:     iconURL,
+		Attachments: attachs,
+		Channel:     msg.Channel,
+		UserName:    msg.Username,
+		Text:        msg.Text,
+	}
+	if msg.Avatar != "" {
+		matterMessage.IconURL = msg.Avatar
+	}
+	if err := b.mh.Send(matterMessage); err != nil {
+		b.Log.Errorf("Failed to send message via webhook: %#v", err)
+		return err
+	}
+	return nil
+}
+
+func (b *Bslack) sendRTM(msg config.Message) (string, error) {
+	// Handle channelmember messages.
+	if handled := b.handleGetChannelMembers(&msg); handled {
+		return "", nil
+	}
+
+	channelInfo, err := b.channels.getChannel(msg.Channel)
+	if err != nil {
+		return "", fmt.Errorf("could not send message: %v", err)
+	}
+	if msg.Event == config.EventUserTyping {
+		if b.GetBool("ShowUserTyping") {
+			b.rtm.SendMessage(b.rtm.NewTypingMessage(channelInfo.ID))
+		}
+		return "", nil
+	}
+
+	var handled bool
+
+	// Handle topic/purpose updates.
+	if handled, err = b.handleTopicOrPurpose(&msg, channelInfo); handled {
+		return "", err
+	}
+
+	// Handle prefix hint for unthreaded messages.
+	if msg.ParentNotFound() {
+		msg.ParentID = ""
+		msg.Text = fmt.Sprintf("[thread]: %s", msg.Text)
+	}
+
+	// Handle message deletions.
+	if handled, err = b.deleteMessage(&msg, channelInfo); handled {
+		return msg.ID, err
+	}
+
+	// Prepend nickname if configured.
+	if b.GetBool(useNickPrefixConfig) {
+		msg.Text = msg.Username + msg.Text
+	}
+
+	// Handle message edits.
+	if handled, err = b.editMessage(&msg, channelInfo); handled {
+		return msg.ID, err
+	}
+
+	// Upload a file if it exists.
+	if len(msg.Extra) > 0 {
+		extraMsgs := helper.HandleExtra(&msg, b.General)
+		for i := range extraMsgs {
+			rmsg := &extraMsgs[i]
+			rmsg.Text = rmsg.Username + rmsg.Text
+			_, err = b.postMessage(rmsg, channelInfo)
+			if err != nil {
+				b.Log.Error(err)
+			}
+		}
+		// Upload files if necessary (from Slack, Telegram or Mattermost).
+		return b.uploadFile(&msg, channelInfo.ID)
+	}
+
+	// Post message.
+	return b.postMessage(&msg, channelInfo)
+}
+
+func (b *Bslack) updateTopicOrPurpose(msg *config.Message, channelInfo *slack.Channel) error {
+	var updateFunc func(channelID string, value string) (*slack.Channel, error)
+
+	incomingChangeType, text := b.extractTopicOrPurpose(msg.Text)
+	switch incomingChangeType {
+	case "topic":
+		updateFunc = b.rtm.SetTopicOfConversation
+	case "purpose":
+		updateFunc = b.rtm.SetPurposeOfConversation
+	default:
+		b.Log.Errorf("Unhandled type received from extractTopicOrPurpose: %s", incomingChangeType)
+		return nil
+	}
+	for {
+		_, err := updateFunc(channelInfo.ID, text)
+		if err == nil {
+			return nil
+		}
+		if err = handleRateLimit(b.Log, err); err != nil {
+			return err
+		}
+	}
+}
+
+// handles updating topic/purpose and determining whether to further propagate update messages.
+func (b *Bslack) handleTopicOrPurpose(msg *config.Message, channelInfo *slack.Channel) (bool, error) {
+	if msg.Event != config.EventTopicChange {
+		return false, nil
+	}
+
+	if b.GetBool("SyncTopic") {
+		return true, b.updateTopicOrPurpose(msg, channelInfo)
+	}
+
+	// Pass along to normal message handlers.
+	if b.GetBool("ShowTopicChange") {
+		return false, nil
+	}
+
+	// Swallow message as handled no-op.
+	return true, nil
+}
+
+func (b *Bslack) deleteMessage(msg *config.Message, channelInfo *slack.Channel) (bool, error) {
+	if msg.Event != config.EventMsgDelete {
+		return false, nil
+	}
+
+	// Some protocols echo deletes, but with an empty ID.
+	if msg.ID == "" {
+		return true, nil
+	}
+
+	for {
+		_, _, err := b.rtm.DeleteMessage(channelInfo.ID, msg.ID)
+		if err == nil {
+			return true, nil
+		}
+
+		if err = handleRateLimit(b.Log, err); err != nil {
+			b.Log.Errorf("Failed to delete user message from Slack: %#v", err)
+			return true, err
+		}
+	}
+}
+
+func (b *Bslack) editMessage(msg *config.Message, channelInfo *slack.Channel) (bool, error) {
+	if msg.ID == "" {
+		return false, nil
+	}
+	messageOptions := b.prepareMessageOptions(msg)
+	for {
+		_, _, _, err := b.rtm.UpdateMessage(channelInfo.ID, msg.ID, messageOptions...)
+		if err == nil {
+			return true, nil
+		}
+
+		if err = handleRateLimit(b.Log, err); err != nil {
+			b.Log.Errorf("Failed to edit user message on Slack: %#v", err)
+			return true, err
+		}
+	}
+}
+
+func (b *Bslack) postMessage(msg *config.Message, channelInfo *slack.Channel) (string, error) {
+	// don't post empty messages
+	if msg.Text == "" {
+		return "", nil
+	}
+	messageOptions := b.prepareMessageOptions(msg)
+	for {
+		_, id, err := b.rtm.PostMessage(channelInfo.ID, messageOptions...)
+		if err == nil {
+			return id, nil
+		}
+
+		if err = handleRateLimit(b.Log, err); err != nil {
+			b.Log.Errorf("Failed to sent user message to Slack: %#v", err)
+			return "", err
+		}
+	}
+}
+
+// uploadFile handles native upload of files
+func (b *Bslack) uploadFile(msg *config.Message, channelID string) (string, error) {
+	var messageID string
+	for _, f := range msg.Extra["file"] {
+		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 = ""
+		}
+		// 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.
+		ts := time.Now()
+		b.Log.Debugf("Adding file %s to cache at %s with timestamp", fi.Name, ts.String())
+		b.cache.Add("filename"+fi.Name, ts)
+		initialComment := fmt.Sprintf("File from %s", msg.Username)
+		if fi.Comment != "" {
+			initialComment += fmt.Sprintf(" with comment: %s", fi.Comment)
+		}
+		res, err := b.sc.UploadFile(slack.FileUploadParameters{
+			Reader:          bytes.NewReader(*fi.Data),
+			Filename:        fi.Name,
+			Channels:        []string{channelID},
+			InitialComment:  initialComment,
+			ThreadTimestamp: msg.ParentID,
+		})
+		if err != nil {
+			b.Log.Errorf("uploadfile %#v", err)
+			return "", err
+		}
+		if res.ID != "" {
+			b.Log.Debugf("Adding file ID %s to cache with timestamp %s", res.ID, ts.String())
+			b.cache.Add("file"+res.ID, ts)
+
+			// search for message id by uploaded file in private/public channels, get thread timestamp from uploaded file
+			if v, ok := res.Shares.Private[channelID]; ok && len(v) > 0 {
+				messageID = v[0].Ts
+			}
+			if v, ok := res.Shares.Public[channelID]; ok && len(v) > 0 {
+				messageID = v[0].Ts
+			}
+		}
+	}
+	return messageID, nil
+}
+
+func (b *Bslack) prepareMessageOptions(msg *config.Message) []slack.MsgOption {
+	params := slack.NewPostMessageParameters()
+	if b.GetBool(useNickPrefixConfig) {
+		params.AsUser = true
+	}
+	params.Username = msg.Username
+	params.LinkNames = 1 // replace mentions
+	params.IconURL = config.GetIconURL(msg, b.GetString(iconURLConfig))
+	params.ThreadTimestamp = msg.ParentID
+	if msg.Avatar != "" {
+		params.IconURL = msg.Avatar
+	}
+
+	var attachments []slack.Attachment
+	// add file attachments
+	attachments = append(attachments, b.createAttach(msg.Extra)...)
+	// add slack attachments (from another slack bridge)
+	if msg.Extra != nil {
+		for _, attach := range msg.Extra[sSlackAttachment] {
+			attachments = append(attachments, attach.([]slack.Attachment)...)
+		}
+	}
+
+	var opts []slack.MsgOption
+	opts = append(opts,
+		// provide regular text field (fallback used in Slack notifications, etc.)
+		slack.MsgOptionText(msg.Text, false),
+
+		// add a callback ID so we can see we created it
+		slack.MsgOptionBlocks(slack.NewSectionBlock(
+			slack.NewTextBlockObject(slack.MarkdownType, msg.Text, false, false),
+			nil, nil,
+			slack.SectionBlockOptionBlockID("matterbridge_"+b.uuid),
+		)),
+
+		slack.MsgOptionEnableLinkUnfurl(),
+	)
+	opts = append(opts, slack.MsgOptionAttachments(attachments...))
+	opts = append(opts, slack.MsgOptionPostMessageParameters(params))
+	return opts
+}
+
+func (b *Bslack) createAttach(extra map[string][]interface{}) []slack.Attachment {
+	var attachements []slack.Attachment
+	for _, v := range extra["attachments"] {
+		entry := v.(map[string]interface{})
+		s := slack.Attachment{
+			Fallback:   extractStringField(entry, "fallback"),
+			Color:      extractStringField(entry, "color"),
+			Pretext:    extractStringField(entry, "pretext"),
+			AuthorName: extractStringField(entry, "author_name"),
+			AuthorLink: extractStringField(entry, "author_link"),
+			AuthorIcon: extractStringField(entry, "author_icon"),
+			Title:      extractStringField(entry, "title"),
+			TitleLink:  extractStringField(entry, "title_link"),
+			Text:       extractStringField(entry, "text"),
+			ImageURL:   extractStringField(entry, "image_url"),
+			ThumbURL:   extractStringField(entry, "thumb_url"),
+			Footer:     extractStringField(entry, "footer"),
+			FooterIcon: extractStringField(entry, "footer_icon"),
+		}
+		attachements = append(attachements, s)
+	}
+	return attachements
+}
+
+func extractStringField(data map[string]interface{}, field string) string {
+	if rawValue, found := data[field]; found {
+		if value, ok := rawValue.(string); ok {
+			return value
+		}
+	}
+	return ""
+}
diff --git a/teleirc/matterbridge/bridge/slack/users_channels.go b/teleirc/matterbridge/bridge/slack/users_channels.go
new file mode 100644
index 0000000..85b944b
--- /dev/null
+++ b/teleirc/matterbridge/bridge/slack/users_channels.go
@@ -0,0 +1,343 @@
+package bslack
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/42wim/matterbridge/bridge/config"
+	"github.com/sirupsen/logrus"
+	"github.com/slack-go/slack"
+)
+
+const minimumRefreshInterval = 10 * time.Second
+
+type users struct {
+	log *logrus.Entry
+	sc  *slack.Client
+
+	users           map[string]*slack.User
+	usersMutex      sync.RWMutex
+	usersSyncPoints map[string]chan struct{}
+
+	refreshInProgress bool
+	earliestRefresh   time.Time
+	refreshMutex      sync.Mutex
+}
+
+func newUserManager(log *logrus.Entry, sc *slack.Client) *users {
+	return &users{
+		log:             log,
+		sc:              sc,
+		users:           make(map[string]*slack.User),
+		usersSyncPoints: make(map[string]chan struct{}),
+		earliestRefresh: time.Now(),
+	}
+}
+
+func (b *users) getUser(id string) *slack.User {
+	b.usersMutex.RLock()
+	user, ok := b.users[id]
+	b.usersMutex.RUnlock()
+	if ok {
+		return user
+	}
+	b.populateUser(id)
+	b.usersMutex.RLock()
+	defer b.usersMutex.RUnlock()
+
+	return b.users[id]
+}
+
+func (b *users) getUsername(id string) string {
+	if user := b.getUser(id); user != nil {
+		if user.Profile.DisplayName != "" {
+			return user.Profile.DisplayName
+		}
+		return user.Name
+	}
+	b.log.Warnf("Could not find user with ID '%s'", id)
+	return ""
+}
+
+func (b *users) getAvatar(id string) string {
+	if user := b.getUser(id); user != nil {
+		return user.Profile.Image48
+	}
+	return ""
+}
+
+func (b *users) populateUser(userID string) {
+	for {
+		b.usersMutex.Lock()
+		_, exists := b.users[userID]
+		if exists {
+			// already in cache
+			b.usersMutex.Unlock()
+			return
+		}
+
+		if syncPoint, ok := b.usersSyncPoints[userID]; ok {
+			// Another goroutine is already populating this user for us so wait on it to finish.
+			b.usersMutex.Unlock()
+			<-syncPoint
+			// We do not return and iterate again to check that the entry does indeed exist
+			// in case the previous query failed for some reason.
+		} else {
+			b.usersSyncPoints[userID] = make(chan struct{})
+			defer func() {
+				// Wake up any waiting goroutines and remove the synchronization point.
+				close(b.usersSyncPoints[userID])
+				delete(b.usersSyncPoints, userID)
+			}()
+			break
+		}
+	}
+
+	// Do not hold the lock while fetching information from Slack
+	// as this might take an unbounded amount of time.
+	b.usersMutex.Unlock()
+
+	user, err := b.sc.GetUserInfo(userID)
+	if err != nil {
+		b.log.Debugf("GetUserInfo failed for %v: %v", userID, err)
+		return
+	}
+
+	b.usersMutex.Lock()
+	defer b.usersMutex.Unlock()
+
+	// Register user information.
+	b.users[userID] = user
+}
+
+func (b *users) invalidateUser(userID string) {
+	b.usersMutex.Lock()
+	defer b.usersMutex.Unlock()
+	delete(b.users, userID)
+}
+
+func (b *users) populateUsers(wait bool) {
+	b.refreshMutex.Lock()
+	if !wait && (time.Now().Before(b.earliestRefresh) || b.refreshInProgress) {
+		b.log.Debugf("Not refreshing user list as it was done less than %v ago.", minimumRefreshInterval)
+		b.refreshMutex.Unlock()
+
+		return
+	}
+	for b.refreshInProgress {
+		b.refreshMutex.Unlock()
+		time.Sleep(time.Second)
+		b.refreshMutex.Lock()
+	}
+	b.refreshInProgress = true
+	b.refreshMutex.Unlock()
+
+	newUsers := map[string]*slack.User{}
+	pagination := b.sc.GetUsersPaginated(slack.GetUsersOptionLimit(200))
+	count := 0
+	for {
+		var err error
+		pagination, err = pagination.Next(context.Background())
+		time.Sleep(time.Second)
+		if err != nil {
+			if pagination.Done(err) {
+				break
+			}
+
+			if err = handleRateLimit(b.log, err); err != nil {
+				b.log.Errorf("Could not retrieve users: %#v", err)
+				return
+			}
+			continue
+		}
+
+		for i := range pagination.Users {
+			newUsers[pagination.Users[i].ID] = &pagination.Users[i]
+		}
+		b.log.Debugf("getting %d users", len(pagination.Users))
+		count++
+		// more > 2000 users, slack will complain and ratelimit. break
+		if count > 10 {
+			b.log.Info("Large slack detected > 2000 users, skipping loading complete userlist.")
+			break
+		}
+	}
+
+	b.usersMutex.Lock()
+	defer b.usersMutex.Unlock()
+	b.users = newUsers
+
+	b.refreshMutex.Lock()
+	defer b.refreshMutex.Unlock()
+	b.earliestRefresh = time.Now().Add(minimumRefreshInterval)
+	b.refreshInProgress = false
+}
+
+type channels struct {
+	log *logrus.Entry
+	sc  *slack.Client
+
+	channelsByID   map[string]*slack.Channel
+	channelsByName map[string]*slack.Channel
+	channelsMutex  sync.RWMutex
+
+	channelMembers      map[string][]string
+	channelMembersMutex sync.RWMutex
+
+	refreshInProgress bool
+	earliestRefresh   time.Time
+	refreshMutex      sync.Mutex
+}
+
+func newChannelManager(log *logrus.Entry, sc *slack.Client) *channels {
+	return &channels{
+		log:             log,
+		sc:              sc,
+		channelsByID:    make(map[string]*slack.Channel),
+		channelsByName:  make(map[string]*slack.Channel),
+		earliestRefresh: time.Now(),
+	}
+}
+
+func (b *channels) getChannel(channel string) (*slack.Channel, error) {
+	if strings.HasPrefix(channel, "ID:") {
+		return b.getChannelByID(strings.TrimPrefix(channel, "ID:"))
+	}
+	return b.getChannelByName(channel)
+}
+
+func (b *channels) getChannelByName(name string) (*slack.Channel, error) {
+	return b.getChannelBy(name, b.channelsByName)
+}
+
+func (b *channels) getChannelByID(id string) (*slack.Channel, error) {
+	return b.getChannelBy(id, b.channelsByID)
+}
+
+func (b *channels) getChannelBy(lookupKey string, lookupMap map[string]*slack.Channel) (*slack.Channel, error) {
+	b.channelsMutex.RLock()
+	defer b.channelsMutex.RUnlock()
+
+	if channel, ok := lookupMap[lookupKey]; ok {
+		return channel, nil
+	}
+	return nil, fmt.Errorf("channel %s not found", lookupKey)
+}
+
+func (b *channels) getChannelMembers(users *users) config.ChannelMembers {
+	b.channelMembersMutex.RLock()
+	defer b.channelMembersMutex.RUnlock()
+
+	membersInfo := config.ChannelMembers{}
+	for channelID, members := range b.channelMembers {
+		for _, member := range members {
+			channelName := ""
+			userName := ""
+			userNick := ""
+			user := users.getUser(member)
+			if user != nil {
+				userName = user.Name
+				userNick = user.Profile.DisplayName
+			}
+			channel, _ := b.getChannelByID(channelID)
+			if channel != nil {
+				channelName = channel.Name
+			}
+			memberInfo := config.ChannelMember{
+				Username:    userName,
+				Nick:        userNick,
+				UserID:      member,
+				ChannelID:   channelID,
+				ChannelName: channelName,
+			}
+			membersInfo = append(membersInfo, memberInfo)
+		}
+	}
+	return membersInfo
+}
+
+func (b *channels) registerChannel(channel slack.Channel) {
+	b.channelsMutex.Lock()
+	defer b.channelsMutex.Unlock()
+
+	b.channelsByID[channel.ID] = &channel
+	b.channelsByName[channel.Name] = &channel
+}
+
+func (b *channels) populateChannels(wait bool) {
+	b.refreshMutex.Lock()
+	if !wait && (time.Now().Before(b.earliestRefresh) || b.refreshInProgress) {
+		b.log.Debugf("Not refreshing channel list as it was done less than %v seconds ago.", minimumRefreshInterval)
+		b.refreshMutex.Unlock()
+		return
+	}
+	for b.refreshInProgress {
+		b.refreshMutex.Unlock()
+		time.Sleep(time.Second)
+		b.refreshMutex.Lock()
+	}
+	b.refreshInProgress = true
+	b.refreshMutex.Unlock()
+
+	newChannelsByID := map[string]*slack.Channel{}
+	newChannelsByName := map[string]*slack.Channel{}
+	newChannelMembers := make(map[string][]string)
+
+	// We only retrieve public and private channels, not IMs
+	// and MPIMs as those do not have a channel name.
+	queryParams := &slack.GetConversationsParameters{
+		ExcludeArchived: true,
+		Types:           []string{"public_channel,private_channel"},
+		Limit:           1000,
+	}
+	for {
+		channels, nextCursor, err := b.sc.GetConversations(queryParams)
+		if err != nil {
+			if err = handleRateLimit(b.log, err); err != nil {
+				b.log.Errorf("Could not retrieve channels: %#v", err)
+				return
+			}
+			continue
+		}
+
+		for i := range channels {
+			newChannelsByID[channels[i].ID] = &channels[i]
+			newChannelsByName[channels[i].Name] = &channels[i]
+			// also find all the members in every channel
+			// comment for now, issues on big slacks
+			/*
+				members, err := b.getUsersInConversation(channels[i].ID)
+				if err != nil {
+					if err = b.handleRateLimit(err); err != nil {
+						b.Log.Errorf("Could not retrieve channel members: %#v", err)
+						return
+					}
+					continue
+				}
+				newChannelMembers[channels[i].ID] = members
+			*/
+		}
+
+		if nextCursor == "" {
+			break
+		}
+		queryParams.Cursor = nextCursor
+	}
+
+	b.channelsMutex.Lock()
+	defer b.channelsMutex.Unlock()
+	b.channelsByID = newChannelsByID
+	b.channelsByName = newChannelsByName
+
+	b.channelMembersMutex.Lock()
+	defer b.channelMembersMutex.Unlock()
+	b.channelMembers = newChannelMembers
+
+	b.refreshMutex.Lock()
+	defer b.refreshMutex.Unlock()
+	b.earliestRefresh = time.Now().Add(minimumRefreshInterval)
+	b.refreshInProgress = false
+}