bridge/slack/handlers.go
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
}