Filter out unwanted messages when sending from Minecraft to Discord

assets/special_messages.json

@@ -0,0 +1,54 @@
+[
+    "joined the game",
+    "left the game",
+
+    "has completed the challenge",
+    "has made the advancement",
+    "has reached the goal",
+
+    "fell off",
+    "fell while climbing",
+    "fell from a high place",
+    "was doomed to fall",
+    "fell too far and was finished by",
+    "was struck by lightning",
+    "went up in flames",
+    "walked into fire",
+    "burned to death",
+    "was burnt to a crisp",
+    "tried to swim in lava",
+    "discovered the floor was lava",
+    "walked into danger zone due to",
+    "suffocated in a wall",
+    "was squished too much",
+    "was squashed by",
+    "drowned",
+    "starved to death",
+    "was pricked to death",
+    "walked into a cactus",
+    "died",
+    "blew up",
+    "was blown up by",
+    "withered away",
+    "was shot by a's skull",
+    "was slain by",
+    "was shot by",
+    "was fireballed by",
+    "was pummeled by",
+    "was killed",
+    "was impaled",
+    "hit the ground too hard",
+    "fell out of the world",
+    "didn't want to live in the same world as",
+    "was roasted in dragon breath",
+    "experienced kinetic energy",
+    "went off with a bang",
+    "was poked to death by a sweet berry bush",
+    "was stung to death",
+    "froze to death",
+    "was frozen to death by",
+    "was skewered by",
+    "was obliterated by a sonically-charged shriek",
+    "left the confines of this world",
+    "Actually, message was too long to deliver fully. Sorry! Here's stripped version: %s"
+]

package.json

@@ -25,7 +25,7 @@
         "format": "prettier --write \"**/*.ts\"",
         "lint": "eslint .",
         "lint-fix": "yarn lint --fix",
-        "start": "node .",
+        "start": "node --disable-warning=ExperimentalWarning .",
         "test": "jest --config=tests/jest.config.js"
     },
     "keywords": [

src/bridge.ts

@@ -1,6 +1,6 @@
+import { DiscordMessage, MinecraftMessage } from "./lib/messages.js";
 import { Message, TextChannel } from "discord.js";
 import { IServer } from "./interfaces.js";
-import { MinecraftMessage } from "./lib/messages.js";
 import { PacketTooBigError } from "./lib/rcon/packet.js";
 import { Rcon } from "./lib/rcon/rcon.js";
 import { Tail } from "tail";
@@ -32,14 +32,21 @@ export class Bridge {
 
         const tail = new Tail(this.serverLogPath);
         tail.on("line", (line: string) => {
-            this.channel.send(line);
+            this.sendToDiscord(line);
         });
 
         tail.on("error", (error: any) => {
             console.log(`Error while tailing log file (${this.serverLogPath}): ${error}`);
         });
     }
 
+    async sendToDiscord(line: string): Promise<void> {
+        const message = await DiscordMessage.filter(line, this.channel);
+        if (!message) return; // Message does not match what we want to send to Discord
+
+        this.channel.send({ content: message, allowedMentions: { parse: ["users", "roles"] } });
+    }
+
     async sendToMinecraft(message: Message): Promise<void> {
         // TODO: Handle errors in send
         const minecraftMsg = MinecraftMessage.format(message);

src/endbot.ts

@@ -10,6 +10,7 @@ export class Endbot extends Client {
         super({
             intents: [
                 GatewayIntentBits.Guilds,
+                GatewayIntentBits.GuildMembers,
                 GatewayIntentBits.GuildMessages,
                 GatewayIntentBits.MessageContent,
             ],

src/lib/messages.ts

@@ -1,4 +1,87 @@
-import { Message } from "discord.js";
+import { Message, TextChannel, escapeMarkdown } from "discord.js";
+import specialMessages from "../../assets/special_messages.json" with { type: "json" };
+
+export class DiscordMessage {
+    static async filter(line: string, channel: TextChannel): Promise<string | void> {
+        const regex = /\[Server thread\/INFO\]: (.*)/;
+        const text = line.match(regex);
+        if (!text) return; // Filter out messages not part of the INFO log
+
+        let message = text[1];
+        // Remove messages of entities dying
+        if (
+            (message.startsWith("Villager") && message.endsWith("'")) ||
+            message.startsWith("Named entity class_")
+        )
+            return;
+
+        // Remove messages that aren't from players or special
+        if (message.startsWith("<")) {
+            message = await this.formatContent(message, channel);
+        } else if (!this.isSpecial(message)) {
+            return;
+        }
+
+        return escapeMarkdown(message);
+    }
+
+    private static async formatContent(message: string, channel: TextChannel): Promise<string> {
+        if (message.includes("@")) message = await this.formatUsersAndRoles(message, channel);
+        if (message.includes("#")) message = this.formatChannels(message, channel);
+        return message;
+    }
+
+    private static async formatUsersAndRoles(
+        message: string,
+        channel: TextChannel,
+    ): Promise<string> {
+        // Members need to be fetched as the cache doesn't always contain all members. Not sure why,
+        // but the cache can be used for roles and channels just fine (as well as members in the
+        // MinecraftMessage class)
+        const members = await channel.guild!.members.fetch();
+        members.forEach((member) => {
+            const memberId = "<@" + member.id + ">";
+            const memberName = "@" + member.displayName;
+            if (message.includes(memberName)) {
+                message = message.replaceAll(memberName, memberId);
+            }
+        });
+
+        const roles = channel.guild!.roles.cache;
+        roles.forEach((role) => {
+            const roleId = "<@&" + role.id + ">";
+            const roleName = "@" + role.name;
+            if (message.includes(roleName)) {
+                message = message.replaceAll(roleName, roleId);
+            }
+        });
+
+        return message;
+    }
+
+    private static formatChannels(message: string, channel: TextChannel): string {
+        const channels = channel.guild!.channels.cache;
+        channels.forEach((discordChannel) => {
+            const channelId = "<#" + discordChannel.id + ">";
+            const channelName = "#" + discordChannel.name;
+            if (message.includes(channelName)) {
+                message = message.replaceAll(channelName, channelId);
+            }
+        });
+
+        return message;
+    }
+
+    private static isSpecial(message: string): boolean {
+        for (const phrase of specialMessages) {
+            if (message.includes(phrase)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
 
 export class MinecraftMessage {
     static format(message: Message): string {

tsconfig.json

@@ -18,6 +18,6 @@
         "composite": true,
         "resolveJsonModule": true
     },
-    "include": ["**/*"],
+    "include": ["**/*", "assets/*.json"],
     "exclude": ["node_modules", "dist"]
 }