t00-multiuser/server/index.ts

import { createReader, createWriter, Endian } from "bufferstuff";
import { WebSocketServer } from "ws";
import Config from "./objects/Config";
import FunkyArray from "./objects/FunkyArray";
import RemoteUser from "./objects/RemoteUser";
import { MessageType } from "./enums/MessageType";
import Database from "./objects/Database";
import { Console } from "hsconsole";

Console.customHeader(`MultiProbe server started at ${new Date()}`);

const users = new FunkyArray<string, RemoteUser>();

new Database(Config.database.address, Config.database.port, Config.database.username, Config.database.password, Config.database.name);

const server = new WebSocketServer({
	port: Config.port
}, () => Console.printInfo(`Server listening at ${Config.port}`));

function sendToAllButSelf(user:RemoteUser, data:Buffer) {
	users.forEach(otherUser => {
		if (otherUser.id !== user.id && otherUser.currentURL === user.currentURL) {
			otherUser.send(data);
		}
	});
}

function sendToAll(user:RemoteUser, data:Buffer) {
	users.forEach(otherUser => {
		if (otherUser.currentURL === user.currentURL) {
			otherUser.send(data);
		}
	});
}

server.on("connection", (socket) => {
	const myUUID = crypto.randomUUID();
	let user:RemoteUser;

	function closeOrError() {
		if (users.has(myUUID)) {
			users.remove(myUUID);

			const userLeftPacket = createWriter(Endian.LE, 5).writeByte(MessageType.ClientLeft).writeUInt(user.id).toBuffer();
			users.forEach(otherUser => otherUser.send(userLeftPacket));
		}
	}

	socket.on("close", closeOrError);
	socket.on("error", closeOrError);

	socket.on("message", async (data) => {
		const reader = createReader(Endian.LE, data as Buffer);
		// There is absolutely no reason we should ever get
		// more than 50 bytes legit.
		if (reader.length > 0 && reader.length < 50) {
			switch (reader.readUByte()) {
				case MessageType.ClientDetails:
					if (user !== undefined) {
						return;
					}
					const username = reader.readShortString();
					const rawURL = reader.readString();
					let page = rawURL.toLowerCase().replace(".htm", "").replace(".html", "");
					if (page === "index") {
						page = "";
					}
					let lengthOfUsernames = 0;
					const usersOnPage = new Array<RemoteUser>();
					await users.forEach(otherUser => {
						if (otherUser.currentURL === page) {
							usersOnPage.push(otherUser);
							lengthOfUsernames += otherUser.username.length + 1; // + 1 for length byte
						}
					});
					const usersToSend = createWriter(Endian.LE, 3 + (usersOnPage.length * 12) + lengthOfUsernames).writeByte(MessageType.Clients).writeUShort(usersOnPage.length);
					for (const otherUser of usersOnPage) {
						usersToSend.writeUInt(otherUser.id).writeShortString(otherUser.username).writeFloat(otherUser.cursorX).writeInt(otherUser.cursorY);
					}
					user = users.set(myUUID, new RemoteUser(socket, username, page, rawURL));
					sendToAllButSelf(user, createWriter(Endian.LE, 6 + username.length).writeByte(MessageType.ClientJoined).writeUInt(user.id).writeShortString(username).toBuffer());
					user.send(usersToSend.toBuffer());
					break;
				case MessageType.CursorPos:
				{
					if (user === undefined) {
						return;
					}
					user.cursorX = reader.readFloat();
					user.cursorY = reader.readInt();
					sendToAllButSelf(user, createWriter(Endian.LE, 13).writeByte(MessageType.CursorPos).writeUInt(user.id).writeFloat(user.cursorX).writeInt(user.cursorY).toBuffer());
					break;
				}
				case MessageType.Ping:
				{
					if (user === undefined) {
						return;
					}

					if ((Date.now() - user.lastPingReset) >= 1000) {
						user.allowedPings = 10;
					}

					if (user.allowedPings > 0) {
						user.allowedPings--;
						const cursorX = reader.readFloat();
						const cursorY = reader.readInt();
						const packet = createWriter(Endian.LE, 9).writeByte(MessageType.Ping).writeFloat(cursorX).writeInt(cursorY).toBuffer();
						sendToAll(user, packet);
					}
					break;
				}
			}
		}
	});
});