Add webhook posting mode for discord. (#204)

Using it implies to configure a Webhook on discord and set the parameter :
- WebhookURL (New parameter, discord-specific)

Discord API does not allow to change the name of the user posting, but webhooks does.
This makes the relay much more elegant, even if we might lose some more advanced features.

Signed-off-by: saury07 <sacha.aury@gmail.com>

bridge/config/config.go

@@ -77,6 +77,7 @@ type Protocol struct {
 	UseSASL                bool   // IRC
 	UseTLS                 bool   // IRC
 	UseFirstName           bool   // telegram
+	WebhookURL	       string // discord
 }
 
 type ChannelOptions struct {

bridge/discord/discord.go

@@ -19,6 +19,8 @@ type bdiscord struct {
 	UseChannelID  bool
 	userMemberMap map[string]*discordgo.Member
 	guildID       string
+	webhookID     string
+	webhookToken  string
 	sync.RWMutex
 }
 
@@ -35,6 +37,12 @@ func New(cfg config.Protocol, account string, c chan config.Message) *bdiscord {
 	b.Remote = c
 	b.Account = account
 	b.userMemberMap = make(map[string]*discordgo.Member)
+	if b.Config.WebhookURL != "" {
+		flog.Debug("Configuring Discord Incoming Webhook")
+		webhookURLSplit := strings.Split(b.Config.WebhookURL, "/")
+		b.webhookToken = webhookURLSplit[len(webhookURLSplit)-1]
+		b.webhookID = webhookURLSplit[len(webhookURLSplit)-2]
+	}
 	return b
 }
 
@@ -101,7 +109,21 @@ func (b *bdiscord) Send(msg config.Message) error {
 		flog.Errorf("Could not find channelID for %v", msg.Channel)
 		return nil
 	}
+	if b.Config.WebhookURL == ""{
+		flog.Debugf("Broadcasting using API")
 		b.c.ChannelMessageSend(channelID, msg.Username+msg.Text)
+	} else {
+		flog.Debugf("Broadcasting using Webhook")
+		b.c.WebhookExecute(
+			b.webhookID,
+			b.webhookToken,
+			true,
+			&discordgo.WebhookParams{
+				Content: msg.Text,
+				Username: msg.Username,
+				AvatarURL: msg.Avatar,
+		})
+	}
 	return nil
 }
 
@@ -122,6 +144,10 @@ func (b *bdiscord) messageCreate(s *discordgo.Session, m *discordgo.MessageCreat
 	if m.Author.Username == b.Nick {
 		return
 	}
+	// if using webhooks, do not relay if it's ours
+	if b.Config.WebhookURL != "" && m.Author.Bot && m.Author.ID == b.webhookID {
+		return
+	}
 	if len(m.Attachments) > 0 {
 		for _, attach := range m.Attachments {
 			m.Content = m.Content + "\n" + attach.URL

matterbridge.toml.sample

@@ -454,6 +454,10 @@ Server="yourservername"
 #OPTIONAL (default false)
 ShowEmbeds=false
 
+#Specify WebhookURL. If given, will relay messages using the Webhook, which gives a better look to messages.
+#OPTIONAL (default empty)
+WebhookURL="Yourwebhooktokenhere"
+
 #Disable sending of edits to other bridges
 #OPTIONAL (default false)
 EditDisable=false