From 2597c9bfacfbc04d1d77162465039eb9b45d0e4d Mon Sep 17 00:00:00 2001
From: Wim <wim@42.be>
Date: Sun, 22 Jul 2018 00:27:49 +0200
Subject: [PATCH] Clip too long messages sent to discord (discord). Closes #440

---
 bridge/discord/discord.go |  6 ++++++
 bridge/helper/helper.go   | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/bridge/discord/discord.go b/bridge/discord/discord.go
index cd06eeaf..db3fb68a 100644
--- a/bridge/discord/discord.go
+++ b/bridge/discord/discord.go
@@ -13,6 +13,8 @@ import (
 	"github.com/bwmarrin/discordgo"
 )
 
+const MessageLength = 1950
+
 type Bdiscord struct {
 	c              *discordgo.Session
 	Channels       []*discordgo.Channel
@@ -141,6 +143,8 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 		if msg.Text == "" {
 			return "", nil
 		}
+
+		msg.Text = helper.ClipMessage(msg.Text, MessageLength)
 		err := b.c.WebhookExecute(
 			wID,
 			wToken,
@@ -167,6 +171,7 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 	// Upload a file if it exists
 	if msg.Extra != nil {
 		for _, rmsg := range helper.HandleExtra(&msg, b.General) {
+			rmsg.Text = helper.ClipMessage(rmsg.Text, MessageLength)
 			b.c.ChannelMessageSend(channelID, rmsg.Username+rmsg.Text)
 		}
 		// check if we have files to upload (from slack, telegram or mattermost)
@@ -175,6 +180,7 @@ func (b *Bdiscord) Send(msg config.Message) (string, error) {
 		}
 	}
 
+	msg.Text = helper.ClipMessage(msg.Text, MessageLength)
 	// Edit message
 	if msg.ID != "" {
 		_, err := b.c.ChannelMessageEdit(channelID, msg.ID, msg.Username+msg.Text)
diff --git a/bridge/helper/helper.go b/bridge/helper/helper.go
index d0c1062c..a13e02af 100644
--- a/bridge/helper/helper.go
+++ b/bridge/helper/helper.go
@@ -8,6 +8,7 @@ import (
 	"regexp"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/42wim/matterbridge/bridge/config"
 	log "github.com/sirupsen/logrus"
@@ -115,3 +116,15 @@ func RemoveEmptyNewLines(msg string) string {
 	lines = strings.TrimRight(lines, "\n")
 	return lines
 }
+
+func ClipMessage(text string, length int) string {
+	// clip too long messages
+	if len(text) > length {
+		text = text[:length-len(" *message clipped*")]
+		if r, size := utf8.DecodeLastRuneInString(text); r == utf8.RuneError {
+			text = text[:len(text)-size]
+		}
+		text += " *message clipped*"
+	}
+	return text
+}