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Add initial transmitter implementation (discord) 

This has been tested with one webhook in one channel.

Sends, edits and deletions work fine
This commit is contained in:
Qais Patankar 2020-11-30 05:47:02 +00:00 committed by Wim
parent 611fb279bc
commit 52e2f926f4
5 changed files with 370 additions and 119 deletions
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192
bridge/discord/discord.go
View File

@ -8,6 +8,7 @@ import (
"github.com/42wim/matterbridge/bridge"
"github.com/42wim/matterbridge/bridge/config"
"github.com/42wim/matterbridge/bridge/discord/transmitter"
"github.com/42wim/matterbridge/bridge/helper"
"github.com/matterbridge/discordgo"
)
@ -19,12 +20,9 @@ type Bdiscord struct {
c *discordgo.Session
nick string
userID string
guildID string
webhookID string
webhookToken string
canEditWebhooks bool
nick string
userID string
guildID string
channelsMutex sync.RWMutex
channels []*discordgo.Channel
@ -33,6 +31,10 @@ type Bdiscord struct {
membersMutex sync.RWMutex
userMemberMap map[string]*discordgo.Member
nickMemberMap map[string]*discordgo.Member
// Webhook specific logic
useAutoWebhooks bool
transmitter *transmitter.Transmitter
}
func New(cfg *bridge.Config) bridge.Bridger {
@ -40,9 +42,17 @@ func New(cfg *bridge.Config) bridge.Bridger {
b.userMemberMap = make(map[string]*discordgo.Member)
b.nickMemberMap = make(map[string]*discordgo.Member)
b.channelInfoMap = make(map[string]*config.ChannelInfo)
if b.GetString("WebhookURL") != "" {
b.Log.Debug("Configuring Discord Incoming Webhook")
b.webhookID, b.webhookToken = b.splitURL(b.GetString("WebhookURL"))
// If WebhookURL is set to anything, we assume preference for autoWebhooks
//
// Legacy note: WebhookURL used to have an actual webhook URL that we would edit,
// but we stopped doing that due to Discord making rate limits more aggressive.
//
// We're keeping the same setting for now, and we will late deprecate this setting
// in favour of a new setting, something like "AutoWebhooks=true"
b.useAutoWebhooks = b.GetString("WebhookURL") != ""
if b.useAutoWebhooks {
b.Log.Debug("Using automatic webhooks")
}
return b
}
@ -137,36 +147,44 @@ func (b *Bdiscord) Connect() error {
return err
}
b.channelsMutex.RLock()
if b.GetString("WebhookURL") == "" {
for _, channel := range b.channels {
b.Log.Debugf("found channel %#v", channel)
}
} else {
manageWebhooks := discordgo.PermissionManageWebhooks
var channelsDenied []string
for _, info := range b.Channels {
id := b.getChannelID(info.Name) // note(qaisjp): this readlocks channelsMutex
b.Log.Debugf("Verifying PermissionManageWebhooks for %s with ID %s", info.ID, id)
// Initialise webhook management
b.transmitter = transmitter.New(b.c, b.guildID, "matterbridge", b.useAutoWebhooks)
b.transmitter.Log = b.Log
perms, permsErr := b.c.UserChannelPermissions(userinfo.ID, id)
if permsErr != nil {
b.Log.Warnf("Failed to check PermissionManageWebhooks in channel \"%s\": %s", info.Name, permsErr.Error())
} else if perms&manageWebhooks == manageWebhooks {
continue
var webhookChannelIDs []string
for _, channel := range b.Channels {
channelID := b.getChannelID(channel.Name) // note(qaisjp): this readlocks channelsMutex
// If a WebhookURL was not explicitly provided for this channel,
// there are two options: just a regular bot message (ugly) or this is should be webhook sent
if channel.Options.WebhookURL == "" {
// If it should be webhook sent, we should enforce this via the transmitter
if b.useAutoWebhooks {
webhookChannelIDs = append(webhookChannelIDs, channelID)
}
channelsDenied = append(channelsDenied, fmt.Sprintf("%#v", info.Name))
continue
}
b.canEditWebhooks = len(channelsDenied) == 0
if b.canEditWebhooks {
b.Log.Info("Can manage webhooks; will edit channel for global webhook on send")
} else {
b.Log.Warn("Can't manage webhooks; won't edit channel for global webhook on send")
b.Log.Warn("Can't manage webhooks in channels: ", strings.Join(channelsDenied, ", "))
whID, whToken, ok := b.splitURL(channel.Options.WebhookURL)
if !ok {
return fmt.Errorf("failed to parse WebhookURL %#v for channel %#v", channel.Options.WebhookURL, channel.ID)
}
b.transmitter.AddWebhook(channelID, &discordgo.Webhook{
ID: whID,
Token: whToken,
GuildID: b.guildID,
ChannelID: channelID,
})
}
if b.useAutoWebhooks {
err = b.transmitter.RefreshGuildWebhooks(webhookChannelIDs)
if err != nil {
b.Log.WithError(err).Println("transmitter could not refresh guild webhooks")
return err
}
}
b.channelsMutex.RUnlock()
// Obtaining guild members and initializing nickname mapping.
b.membersMutex.Lock()
@ -223,23 +241,9 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
msg.Text = "_" + msg.Text + "_"
}
// use initial webhook configured for the entire Discord account
isGlobalWebhook := true
wID := b.webhookID
wToken := b.webhookToken
// check if have a channel specific webhook
b.channelsMutex.RLock()
if ci, ok := b.channelInfoMap[msg.Channel+b.Account]; ok {
if ci.Options.WebhookURL != "" {
wID, wToken = b.splitURL(ci.Options.WebhookURL)
isGlobalWebhook = false
}
}
b.channelsMutex.RUnlock()
// Use webhook to send the message
if wID != "" && msg.Event != config.EventMsgDelete {
useWebhooks := b.shouldMessageUseWebhooks(&msg)
if useWebhooks && msg.Event != config.EventMsgDelete {
// skip events
if msg.Event != "" && msg.Event != config.EventUserAction && msg.Event != config.EventJoinLeave && msg.Event != config.EventTopicChange {
return "", nil
@ -260,32 +264,18 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
if msg.ID != "" {
b.Log.Debugf("Editing webhook message")
uri := discordgo.EndpointWebhookToken(wID, wToken) + "/messages/" + msg.ID
_, err := b.c.RequestWithBucketID("PATCH", uri, discordgo.WebhookParams{
err := b.transmitter.Edit(channelID, msg.ID, &discordgo.WebhookParams{
Content: msg.Text,
Username: msg.Username,
}, discordgo.EndpointWebhookToken("", ""))
})
if err == nil {
return msg.ID, nil
}
b.Log.Errorf("Could not edit webhook message: %s", err)
}
b.Log.Debugf("Broadcasting using Webhook")
// if we have a global webhook for this Discord account, and permission
// to modify webhooks (previously verified), then set its channel to
// the message channel before using it.
if isGlobalWebhook && b.canEditWebhooks {
b.Log.Debugf("Setting webhook channel to \"%s\"", msg.Channel)
_, err := b.c.WebhookEdit(wID, "", "", channelID)
if err != nil {
b.Log.Errorf("Could not set webhook channel: %s", err)
return "", err
}
}
b.Log.Debugf("Processing webhook sending for message %#v", msg)
msg, err := b.webhookSend(&msg, wID, wToken)
msg, err := b.webhookSend(&msg, channelID)
if err != nil {
b.Log.Errorf("Could not broadcast via webook for message %#v: %s", msg, err)
return "", err
@ -339,46 +329,6 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
return res.ID, nil
}
// useWebhook returns true if we have a webhook defined somewhere
func (b *Bdiscord) useWebhook() bool {
if b.GetString("WebhookURL") != "" {
return true
}
b.channelsMutex.RLock()
defer b.channelsMutex.RUnlock()
for _, channel := range b.channelInfoMap {
if channel.Options.WebhookURL != "" {
return true
}
}
return false
}
// isWebhookID returns true if the specified id is used in a defined webhook
func (b *Bdiscord) isWebhookID(id string) bool {
if b.GetString("WebhookURL") != "" {
wID, _ := b.splitURL(b.GetString("WebhookURL"))
if wID == id {
return true
}
}
b.channelsMutex.RLock()
defer b.channelsMutex.RUnlock()
for _, channel := range b.channelInfoMap {
if channel.Options.WebhookURL != "" {
wID, _ := b.splitURL(channel.Options.WebhookURL)
if wID == id {
return true
}
}
}
return false
}
// handleUploadFile handles native upload of files
func (b *Bdiscord) handleUploadFile(msg *config.Message, channelID string) (string, error) {
var err error
@ -401,10 +351,26 @@ func (b *Bdiscord) handleUploadFile(msg *config.Message, channelID string) (stri
return "", nil
}
// shouldMessageUseWebhooks checks if have a channel specific webhook, if we're not using auto webhooks
func (b *Bdiscord) shouldMessageUseWebhooks(msg *config.Message) bool {
if b.useAutoWebhooks {
return true
}
b.channelsMutex.RLock()
defer b.channelsMutex.RUnlock()
if ci, ok := b.channelInfoMap[msg.Channel+b.Account]; ok {
if ci.Options.WebhookURL != "" {
return true
}
}
return false
}
// webhookSend send one or more message via webhook, taking care of file
// uploads (from slack, telegram or mattermost).
// Returns messageID and error.
func (b *Bdiscord) webhookSend(msg *config.Message, webhookID, token string) (*discordgo.Message, error) {
func (b *Bdiscord) webhookSend(msg *config.Message, channelID string) (*discordgo.Message, error) {
var (
res *discordgo.Message
err error
@ -427,10 +393,8 @@ func (b *Bdiscord) webhookSend(msg *config.Message, webhookID, token string) (*d
// We can't send empty messages.
if msg.Text != "" {
res, err = b.c.WebhookExecute(
webhookID,
token,
true,
res, err = b.transmitter.Send(
channelID,
&discordgo.WebhookParams{
Content: msg.Text,
Username: msg.Username,
@ -454,10 +418,8 @@ func (b *Bdiscord) webhookSend(msg *config.Message, webhookID, token string) (*d
if msg.Text == "" {
content = fi.Comment
}
_, e2 := b.c.WebhookExecute(
webhookID,
token,
false,
_, e2 := b.transmitter.Send(
channelID,
&discordgo.WebhookParams{
Username: msg.Username,
AvatarURL: msg.Avatar,

2
bridge/discord/handlers.go
View File

@ -69,7 +69,7 @@ func (b *Bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreat
return
}
// if using webhooks, do not relay if it's ours
if b.useWebhook() && m.Author.Bot && b.isWebhookID(m.Author.ID) {
if m.Author.Bot && b.transmitter.HasWebhook(m.Author.ID) {
return
}

6
bridge/discord/helpers.go
View File

@ -196,7 +196,7 @@ func (b *Bdiscord) replaceAction(text string) (string, bool) {
}
// splitURL splits a webhookURL and returns the ID and token.
func (b *Bdiscord) splitURL(url string) (string, string) {
func (b *Bdiscord) splitURL(url string) (string, string, bool) {
const (
expectedWebhookSplitCount = 7
webhookIdxID = 5
@ -204,9 +204,9 @@ func (b *Bdiscord) splitURL(url string) (string, string) {
)
webhookURLSplit := strings.Split(url, "/")
if len(webhookURLSplit) != expectedWebhookSplitCount {
b.Log.Fatalf("%s is no correct discord WebhookURL", url)
return "", "", false
}
return webhookURLSplit[webhookIdxID], webhookURLSplit[webhookIdxToken]
return webhookURLSplit[webhookIdxID], webhookURLSplit[webhookIdxToken], true
}
func enumerateUsernames(s string) []string {

257
bridge/discord/transmitter/transmitter.go Normal file
View File

@ -0,0 +1,257 @@
// Package transmitter provides functionality for transmitting
// arbitrary webhook messages to Discord.
//
// The package provides the following functionality:
// - Creating new webhooks, whenever necessary
// - Loading webhooks that we have previously created
// - Sending new messages
// - Editing messages, via message ID
// - Deleting messages, via message ID
//
// The package has been designed for matterbridge, but with other
// Go bots in mind. The public API should be matterbridge-agnostic.
package transmitter
import (
"errors"
"fmt"
"strings"
"sync"
"time"
"github.com/matterbridge/discordgo"
log "github.com/sirupsen/logrus"
)
// A Transmitter represents a message manager for a single guild.
type Transmitter struct {
session *discordgo.Session
guild string
title string
autoCreate bool
// channelWebhooks maps from a channel ID to a webhook instance
channelWebhooks map[string]*discordgo.Webhook
mutex sync.RWMutex
Log *log.Entry
}
// ErrWebhookNotFound is returned when a valid webhook for this channel/message combination does not exist
var ErrWebhookNotFound = errors.New("webhook for this channel and message does not exist")
// ErrPermissionDenied is returned if the bot does not have permission to manage webhooks.
//
// It's important to note that:
// - a bot can have both a guild-wide permission and a channel-specific permission to manage webhooks
// - even if a bot has permission to manage the guild's webhooks, there could be channel specific overrides
var ErrPermissionDenied = errors.New("missing 'Manage Webhooks' permission")
// New returns a new Transmitter given a Discord session, guild ID, and title.
func New(session *discordgo.Session, guild string, title string, autoCreate bool) *Transmitter {
return &Transmitter{
session: session,
guild: guild,
title: title,
autoCreate: autoCreate,
channelWebhooks: make(map[string]*discordgo.Webhook),
Log: log.NewEntry(nil),
}
}
// Send transmits a message to the given channel with the provided webhook data.
//
// Note that this function will wait until Discord responds with an answer.
func (t *Transmitter) Send(channelID string, params *discordgo.WebhookParams) (*discordgo.Message, error) {
wh, err := t.getOrCreateWebhook(channelID)
if err != nil {
return nil, err
}
msg, err := t.session.WebhookExecute(wh.ID, wh.Token, true, params)
if err != nil {
return nil, fmt.Errorf("execute failed: %w", err)
}
return msg, nil
}
// Edit will edit a message in a channel, if possible.
func (t *Transmitter) Edit(channelID string, messageID string, params *discordgo.WebhookParams) error {
wh := t.getWebhook(channelID)
if wh == nil {
return ErrWebhookNotFound
}
uri := discordgo.EndpointWebhookToken(wh.ID, wh.Token) + "/messages/" + messageID
_, err := t.session.RequestWithBucketID("PATCH", uri, params, discordgo.EndpointWebhookToken("", ""))
if err != nil {
return err
}
return nil
}
// HasWebhook checks whether the transmitter is using a particular webhook.
func (t *Transmitter) HasWebhook(id string) bool {
t.mutex.RLock()
defer t.mutex.RUnlock()
for _, wh := range t.channelWebhooks {
if wh.ID == id {
return true
}
}
return false
}
// AddWebhook allows you to register a channel's webhook with the transmitter.
func (t *Transmitter) AddWebhook(channelID string, webhook *discordgo.Webhook) (replaced bool) {
t.Log.Debugf("Manually added webhook %#v to channel %#v", webhook.ID, channelID)
t.mutex.Lock()
defer t.mutex.Unlock()
_, replaced := t.channelWebhooks[channelID]
t.channelWebhooks[channelID] = webhook
return replaced
}
// RefreshGuildWebhooks loads "relevant" webhooks into the transmitter, with careful permission handling.
//
// Notes:
// - A webhook is "relevant" if it was created by this bot -- the ApplicationID should match the bot's ID.
// - The term "having permission" means having the "Manage Webhooks" permission. See ErrPermissionDenied for more information.
// - This function is additive and will not unload previously loaded webhooks.
// - A nil channelIDs slice is treated the same as an empty one.
//
// If the bot has guild-wide permission:
// 1. it will load any "relevant" webhooks from the entire guild
// 2. the given slice is ignored
//
// If the bot does not have guild-wide permission:
// 1. it will load any "relevant" webhooks in each channel
// 2. a single error will be returned if any error occurs (incl. if there is no permission for any of these channels)
//
// If any channel has more than one "relevant" webhook, it will randomly pick one.
func (t *Transmitter) RefreshGuildWebhooks(channelIDs []string) error {
t.Log.Debugln("Refreshing guild webhooks")
botID, err := getDiscordUserID(t.session)
if err != nil {
return fmt.Errorf("could not get current user: %w", err)
}
// Get all existing webhooks
hooks, err := t.session.GuildWebhooks(t.guild)
if err != nil {
switch {
case isDiscordPermissionError(err):
// We fallback on manually fetching hooks from individual channels
// if we don't have the "Manage Webhooks" permission globally.
// We can only do this if we were provided channelIDs, though.
if len(channelIDs) == 0 {
return ErrPermissionDenied
}
t.Log.Debugln("Missing global 'Manage Webhooks' permission, falling back on per-channel permission")
return t.fetchChannelsHooks(channelIDs, botID)
default:
return fmt.Errorf("could not get webhooks: %w", err)
}
}
t.Log.Debugln("Refreshing guild webhooks using global permission")
t.assignHooksByAppID(hooks, botID, false)
return nil
}
// createWebhook creates a webhook for a specific channel.
func (t *Transmitter) createWebhook(channel string) (*discordgo.Webhook, error) {
t.mutex.Lock()
defer t.mutex.Unlock()
wh, err := t.session.WebhookCreate(channel, t.title+time.Now().Format(" 3:04:05PM"), "")
if err != nil {
return nil, err
}
t.channelWebhooks[channel] = wh
return wh, nil
}
func (t *Transmitter) getWebhook(channel string) *discordgo.Webhook {
t.mutex.RLock()
defer t.mutex.RUnlock()
return t.channelWebhooks[channel]
}
func (t *Transmitter) getOrCreateWebhook(channelID string) (*discordgo.Webhook, error) {
// If we have a webhook for this channel, immediately return it
wh := t.getWebhook(channelID)
if wh != nil {
return wh, nil
}
// Early exit if we don't want to automatically create one
if !t.autoCreate {
return nil, ErrWebhookNotFound
}
t.Log.Infof("Creating a webhook for %s\n", channelID)
wh, err := t.createWebhook(channelID)
if err != nil {
return nil, fmt.Errorf("could not create webhook: %w", err)
}
return wh, nil
}
// fetchChannelsHooks fetches hooks for the given channelIDs and calls assignHooksByAppID for each channel's hooks
func (t *Transmitter) fetchChannelsHooks(channelIDs []string, botID string) error {
// For each channel, search for relevant hooks
var failedHooks []string
for _, channelID := range channelIDs {
hooks, err := t.session.ChannelWebhooks(channelID)
if err != nil {
failedHooks = append(failedHooks, "\n- "+channelID+": "+err.Error())
continue
}
t.assignHooksByAppID(hooks, botID, true)
}
// Compose an error if any hooks failed
if len(failedHooks) > 0 {
return errors.New("failed to fetch hooks:" + strings.Join(failedHooks, ""))
}
return nil
}
func (t *Transmitter) assignHooksByAppID(hooks []*discordgo.Webhook, appID string, channelTargeted bool) {
logLine := "Picking up webhook"
if channelTargeted {
logLine += " (channel targeted)"
}
t.mutex.Lock()
defer t.mutex.Unlock()
for _, wh := range hooks {
if wh.ApplicationID != appID {
continue
}
t.channelWebhooks[wh.ChannelID] = wh
t.Log.WithFields(log.Fields{
"id": wh.ID,
"name": wh.Name,
"channel": wh.ChannelID,
}).Println(logLine)
break
}
}

32
bridge/discord/transmitter/utils.go Normal file
View File

@ -0,0 +1,32 @@
package transmitter
import (
"github.com/matterbridge/discordgo"
)
// isDiscordPermissionError returns false for nil, and true if a Discord RESTError with code discordgo.ErrorCodeMissionPermissions
func isDiscordPermissionError(err error) bool {
if err == nil {
return false
}
restErr, ok := err.(*discordgo.RESTError)
if !ok {
return false
}
return restErr.Message != nil && restErr.Message.Code == discordgo.ErrCodeMissingPermissions
}
// getDiscordUserID gets own user ID from state, and fallback on API request
func getDiscordUserID(session *discordgo.Session) (string, error) {
if user := session.State.User; user != nil {
return user.ID, nil
}
user, err := session.User("@me")
if err != nil {
return "", err
}
return user.ID, nil
}