MSAgent-Chat/server/src/client.ts

import EventEmitter from 'events';
import { WebSocket } from 'ws';
import {
	MSAgentAdminBanMessage,
	MSAgentAdminGetIPMessage,
	MSAgentAdminGetIPResponse,
	MSAgentAdminKickMessage,
	MSAgentAdminLoginMessage,
	MSAgentAdminLoginResponse,
	MSAgentAdminMessage,
	MSAgentAdminOperation,
	MSAgentErrorMessage,
	MSAgentSendImageMessage,
	MSAgentJoinMessage,
	MSAgentProtocolMessage,
	MSAgentProtocolMessageType,
	MSAgentTalkMessage,
	MSAgentPlayAnimationMessage
} from '@msagent-chat/protocol';
import { MSAgentChatRoom } from './room.js';
import * as htmlentities from 'html-entities';
import RateLimiter from './ratelimiter.js';
import { createHash } from 'crypto';

// Event types

export interface Client {
	on(event: 'join', listener: () => void): this;
	on(event: 'close', listener: () => void): this;
	on(event: 'talk', listener: (msg: string) => void): this;
	on(event: 'animation', listener: (anim: string) => void): this;
	on(event: 'image', listener: (id: string) => void): this;

	on(event: string, listener: Function): this;
}

export class Client extends EventEmitter {
	ip: string;
	username: string | null;
	agent: string | null;
	admin: boolean;

	room: MSAgentChatRoom;
	socket: WebSocket;

	nopTimer: NodeJS.Timeout | undefined;
	nopLevel: number;

	chatRateLimit: RateLimiter;
	animRateLimit: RateLimiter;

	constructor(socket: WebSocket, room: MSAgentChatRoom, ip: string) {
		super();
		this.socket = socket;
		this.ip = ip;
		this.room = room;
		this.username = null;
		this.agent = null;
		this.admin = false;
		this.resetNop();
		this.nopLevel = 0;

		this.chatRateLimit = new RateLimiter(this.room.config.ratelimits.chat);
		this.animRateLimit = new RateLimiter(this.room.config.ratelimits.anim);

		this.socket.on('message', (msg, isBinary) => {
			if (isBinary) {
				this.socket.close();
				return;
			}
			this.parseMessage(msg.toString('utf-8'));
		});
		this.socket.on('error', () => {});
		this.socket.on('close', () => {
			this.emit('close');
		});
	}

	send(msg: MSAgentProtocolMessage) {
		return new Promise<void>((res, rej) => {
			if (this.socket.readyState !== WebSocket.OPEN) {
				res();
				return;
			}
			this.socket.send(JSON.stringify(msg), (err) => {
				if (err) {
					rej(err);
					return;
				}
				res();
			});
		});
	}

	private resetNop() {
		clearInterval(this.nopTimer);
		this.nopLevel = 0;
		this.nopTimer = setInterval(() => {
			if (this.nopLevel++ >= 3) {
				this.socket.close();
			} else {
				this.send({
					op: MSAgentProtocolMessageType.KeepAlive
				});
			}
		}, 10000);
	}

	private async parseMessage(data: string) {
		let msg: MSAgentProtocolMessage;
		try {
			msg = JSON.parse(data);
		} catch {
			this.socket.close();
			return;
		}
		this.resetNop();
		switch (msg.op) {
			case MSAgentProtocolMessageType.Join: {
				let joinMsg = msg as MSAgentJoinMessage;
				if (this.username !== null || !joinMsg.data || !joinMsg.data.username || !joinMsg.data.username) {
					this.socket.close();
					return;
				}
				let username = joinMsg.data.username.trim();
				if (!validateUsername(username)) {
					let msg: MSAgentErrorMessage = {
						op: MSAgentProtocolMessageType.Error,
						data: {
							error: 'Usernames can contain only numbers, letters, spaces, dashes, underscores, and dots, and it must be between 3 and 20 characters.'
						}
					};
					await this.send(msg);
					this.socket.close();
					return;
				}
				if (this.room.config.bannedWords.some((w) => username.indexOf(w) !== -1)) {
					this.socket.close();
					return;
				}
				if (this.room.clients.some((u) => u.username === username)) {
					let i = 1;
					let uo = username;
					do {
						username = uo + i++;
					} while (this.room.clients.some((u) => u.username === username));
				}
				if (!this.room.agents.some((a) => a.filename === joinMsg.data.agent)) {
					this.socket.close();
					return;
				}
				this.username = username;
				this.agent = joinMsg.data.agent;
				this.emit('join');
				break;
			}
			case MSAgentProtocolMessageType.Talk: {
				let talkMsg = msg as MSAgentTalkMessage;
				if (!talkMsg.data || !talkMsg.data.msg || !this.chatRateLimit.request()) {
					return;
				}
				if (talkMsg.data.msg.length > this.room.config.charlimit) return;
				if (this.room.config.bannedWords.some((w) => talkMsg.data.msg.toLowerCase().indexOf(w.toLowerCase()) !== -1)) {
					return;
				}
				this.emit('talk', talkMsg.data.msg);
				break;
			}
			case MSAgentProtocolMessageType.PlayAnimation: {
				let animMsg = msg as MSAgentPlayAnimationMessage;
				if (!animMsg.data || !animMsg.data.anim || !this.animRateLimit.request()) return;
				this.emit('animation', animMsg.data.anim);
				break;
			}
			case MSAgentProtocolMessageType.SendImage: {
				let imgMsg = msg as MSAgentSendImageMessage;
				if (!imgMsg.data || !imgMsg.data.id || !this.chatRateLimit.request()) return;
				this.emit('image', imgMsg.data.id);
				break;
			}
			case MSAgentProtocolMessageType.Admin: {
				let adminMsg = msg as MSAgentAdminMessage;
				if (!adminMsg.data) return;
				switch (adminMsg.data.action) {
					case MSAgentAdminOperation.Login: {
						let loginMsg = adminMsg as MSAgentAdminLoginMessage;
						if (this.admin || !loginMsg.data.password) return;
						let sha256 = createHash('sha256');
						sha256.update(loginMsg.data.password);
						let hash = sha256.digest('hex');
						sha256.destroy();
						let success = false;
						if (hash === this.room.config.adminPasswordHash) {
							this.admin = true;
							success = true;
							this.emit('admin');
						}
						let res: MSAgentAdminLoginResponse = {
							op: MSAgentProtocolMessageType.Admin,
							data: {
								action: MSAgentAdminOperation.Login,
								success
							}
						};
						this.send(res);
						break;
					}
					case MSAgentAdminOperation.GetIP: {
						let getIPMsg = adminMsg as MSAgentAdminGetIPMessage;
						if (!this.admin || !getIPMsg.data || !getIPMsg.data.username) return;
						let _user = this.room.clients.find((c) => c.username === getIPMsg.data.username);
						if (!_user) return;
						let res: MSAgentAdminGetIPResponse = {
							op: MSAgentProtocolMessageType.Admin,
							data: {
								action: MSAgentAdminOperation.GetIP,
								username: _user.username!,
								ip: _user.ip
							}
						};
						this.send(res);
						break;
					}
					case MSAgentAdminOperation.Kick: {
						let kickMsg = adminMsg as MSAgentAdminKickMessage;
						if (!this.admin || !kickMsg.data || !kickMsg.data.username) return;
						let _user = this.room.clients.find((c) => c.username === kickMsg.data.username);
						if (!_user) return;
						let res: MSAgentErrorMessage = {
							op: MSAgentProtocolMessageType.Error,
							data: {
								error: 'You have been kicked.'
							}
						};
						await _user.send(res);
						_user.socket.close();
						break;
					}
					case MSAgentAdminOperation.Ban: {
						let banMsg = adminMsg as MSAgentAdminBanMessage;
						if (!this.admin || !banMsg.data || !banMsg.data.username) return;
						let _user = this.room.clients.find((c) => c.username === banMsg.data.username);
						if (!_user) return;
						let res: MSAgentErrorMessage = {
							op: MSAgentProtocolMessageType.Error,
							data: {
								error: 'You have been banned.'
							}
						};
						await this.room.db.banUser(_user.ip, _user.username!);
						await _user.send(res);
						_user.socket.close();
						break;
					}
				}
				break;
			}
		}
	}
}

function validateUsername(username: string) {
	return username.length >= 3 && username.length <= 20 && /^[a-zA-Z0-9\ \-\_\.]+$/.test(username);
}