http-server.js

const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const pty = require('node-pty');
const { isUndefined } = require('util');
const cors = require('cors');
const { execSync } = require('child_process');
const { stringify } = require('querystring');
const { exit } = require('process');
const fs = require('fs');
const os = require('os');

const fav_shell = "/usr/bin/zsh"

// const app = express();
// const server = http.createServer(app);
// const io = new Server(server);

// Serve static files (your index.html)
// app.use(
//     (req, res, next) => {
//         res.setHeader('Access-Control-Allow-Origin', '*');
//         next();
//     },
//     express.static('public')
// );


const app = express();
const server = http.createServer(app);
const io = new Server(server, {
    cors: {
        origin: '*', // Allow all origins (for development)
        methods: ['GET', 'POST'],
        allowedHeaders: ['Content-Type'],
        // credentials: true // Include credentials if needed
    },
});

app.use(cors(),
    express.static('public')
); // Enable CORS for all routes


// app.use();

// Store terminal instances for each socket connection
const terminals = {};

io.on('connection', (socket) => {
    console.log('Client connected');

    io._opts.pingInterval = 25000; // Adjust to control how often pings are sent
    io._opts.pingTimeout = 5000;   // Adjust to control how long to wait for a ping response
    io._opts.transports = ['websocket']; // Use only WebSocket for faster communication
    io._opts.perMessageDeflate = {
        threshold: 1024 // Enable message compression for messages larger than 1KB
    };
    io._opts.cookie = false; // Disable cookies to reduce overhead

    // Handle new terminal request
    socket.on('new-terminal', (shell) => {
        console.log(shell);
        var command = null;
        // exit();
        if (shell != fav_shell) {
            // it is a command not a shell
            command = shell;
            shell = fav_shell;
        }

        // Create a new shell for this terminal instance
        shell = pty.spawn(shell, [], {
            name: 'xterm-256color',
            cols: 80,
            rows: 30,
            cwd: process.env.HOME,
            env: { ...process.env, TERM: 'xterm-256color' },
        });


        // code 10: Enter
        // some code to easily track last executed command
        // shell.write("preexec(){echo XXX-'$*'-XXX}" + String.fromCharCode(27, 13));

        // shell.write('r() { echo -e XXX-"$*"-XXX; eval "$*" && echo "XXX-OK-XXX" || echo "XXX-ERR-XXX"; } \n');
        // shell.write("clear" + String.fromCharCode(13));
        // socket.emit("clear");
        // shell.write('# start your commands with rec to record them for automation' + String.fromCharCode(13));
        if (command)
            shell.write(command + String.fromCharCode(10));

        // Handle data from the shell
        shell.on('data', (data) => {
            var extractedCommand = ""; // extract command!
            datalines = data.split('\n');
            datalines.forEach((line) => {
                line = line.replace(/\n/g, '\r\n');
                // DEBUG
                // let charCodes = [];
                // for (let i = 0; i < line.length; i++) {
                //     charCodes.push(line.charCodeAt(i));
                // }
                // console.log(line);
                // console.log("Character codes: " + charCodes.join(', '));
                // charCodes = [];



                const regex = /XXX-(.*?)\-XXX/;
                // console.log("line : " + line);
                const match = line.match(regex);

                // Check if there is a match
                if (match) {
                    extractedCommand = match[1].trim(); // Extract the text

                    // Remove the extracted text and the markers from the original string
                    data = line.replace(regex, ''); // Remove the matched part and trim any extra spaces
                    console.log("command: " + extractedCommand);
                    if (extractedCommand == "cls" || extractedCommand == "clear") {
                        socket.emit("clear");
                        extractedCommand = "";
                    }
                    // else if (extractedCommand == "done") {
                    //     console.log('==> done');
                    //     socket.emit('done');
                    //     extractedCommand = "";
                    // }
                    else if (extractedCommand == "exit") {
                        console.log('==> ALERT');
                        socket.emit('ALERT');
                        extractedCommand = "";
                    }
                    else if (extractedCommand == "ERR") {
                        socket.emit("ERR");
                        console.log('==> ERR');
                        extractedCommand = "";
                    }
                    else if (extractedCommand == "OK") {
                        socket.emit("OK");
                        console.log('==> OK');
                        extractedCommand = "";
                    }
                    socket.emit("command", { extractedCommand });
                }

            });
            socket.emit('output', data);
            if (extractedCommand == "exit") {
                console.log('==> exit');
                socket.emit('exit');
                extractedCommand = "";
            }

        });

        shell.onExit(() => {
            socket.emit('exit');
        });


        // Handle input from the client
        socket.on('input', (inputData) => {
            const data = inputData;
            // console.log("web: " + data.charCodeAt(0));
            shell.write(data);
        });


        // Handle shell exit
        socket.on('disconnect', () => {
            shell.kill(); // Kill the associated shell when the client disconnects
            console.log('Client disconnected');
        });

        // Handle Resizing
        socket.on('resize', (resizeData) => {
            // console.log(resizeData)
            const { id, new_w, new_h } = resizeData;
            // console.log("resize : ", id, new_w, new_h)
            if (new_w <= 0 || new_h <= 0 || new_w == undefined || new_h == undefined)
                return;

            // console.log("resizing to: " + new_w + "," + new_h);
            shell.resize(new_w, new_h);
        });

        // Listen for a command to get environment variables
        socket.on('getEnvVar', (varName) => {
            const value = fs.readFileSync(process.env.HOME+'/.gvars/'+varName.slice(1), 'utf8').trim();
            console.log("variable#> " + varName + ":" + value);
            socket.emit('envVarResponse', { varName, value });
        });
    });
});

// Start the server
server.listen(3000, () => {
    console.log('Server is listening on http://localhost:3000');
});