server/src/index.ts

/*
Created by Anne Lefebvre and Anuj Panthri - 2023
Handles the HTTP file serving and the WebSocket connect for HapticTouch
*/

import express, { Application, Request, Response } from "express";
import * as http from "http";
import * as WebSocket from "ws";
import { HapticLinkServer } from "./socket/hapticLinkServer";
import { registerRoutes } from "./socket/routes";
import WebSocketWrapper from "./socket/WebSocketAdapter";
import pino from "pino";
import path from "path";

// If started with --silent, then logging will be disabled.
(() => {
    const args = process.argv;
    if (args.includes("--silent")) {
        return main(false);
    }

    return main(true);
})();

/**
 * Starts HTTP(S) and WS server, initializes HapticLinkServer and handles routing.
 * @param {boolean} logging - Defaults true
 */
function main(logging: boolean = true) {

    // Added by Anuj
    const PING_INTERVAL = parseInt(process.env.PING_INTERVAL as string, 10) || 5 * 1000;
    interface LooseWebSocket extends WebSocket {
        isAlive?: boolean
    }

    const port: number = parseInt(process.env.PORT as string, 10) || 3000;
    const logger = pino({
        level: logging ? "info" : "silent",
        formatters: {
            bindings(bindings) {
                return {
                    level: bindings.level,
                    time: bindings.time,
                    msg: bindings.msg,
                };
            },
        },
    });

    const app: Application = express();
    const server = http.createServer(app);
    const wss = new WebSocket.Server({ server });

    // The entire build/web directory is statically served.
    app.use(express.static(path.join(__dirname, "../../client/build/web")));

    // Catch all. If we want to add pages later, then we should probably change this.
    app.get("*", (_req: Request, res: Response) => {
        res.sendFile(path.join(__dirname + "/../../client/build/web/index.html"));
    });

    // Routes are in socket/routes/*.ts
    // registerRoutes imports and adds them all to router
    const hapticLink = new HapticLinkServer();
    registerRoutes(hapticLink);

    // When a user sends a message, the router checks if that route is available
    // and then calls the handler. It also generates a User object for them to store
    // data for later requests such as an ID
    wss.on("connection", (ws: LooseWebSocket) => {
        logger.info("Client Connected");
        const wsw = new WebSocketWrapper(ws);

        ws.isAlive = true;  // Added by Anuj

        ws.on("message", (message: string) => {
            logger.info(`Received Message: ${message}`);
            hapticLink.handleRoute(wsw, message);
        });

        // Added by Anuj
        // When receive pong from a client this is triggered
        ws.on('pong', () => {
            ws.isAlive = true;
            logger.info("received pong");
        });

        // Added by Anuj
        // When receive ping from a client this is triggered
        ws.on('ping', () => {
            logger.info("received ping");
        });

        // When a user disconnects, their account is removed, and they are removed from all groups
        ws.on("close", () => {
            hapticLink.removeUser(wsw);
        });
        ws.on("error", () => {
            hapticLink.removeUser(wsw);
        });

        ws.send("Welcome");
    });


    // Added by Anuj
    const interval = setInterval(function ping() {
        wss.clients.forEach((ws) => {
            const client = ws as LooseWebSocket;
            if (client.isAlive === false) return ws.terminate();

            ws.ping();
            client.isAlive = false;
        });
    }, PING_INTERVAL);

    // Added by Anuj
    wss.on('close', function close() {
        clearInterval(interval);
    });

    server.listen(port, () => {
        logger.info(`Server is running on port ${port}`);
    });
}