eval-server/index.js

const { VM } = require('vm2')
const { Server } = require('socket.io')
const util = require('util')
const { stylize } = require('./colors')
const randomstring = require('randomstring')
const ChatMessage = require('prismarine-chat')('1.20.1')
const mc = require('minecraft-protocol')
const moment = require('moment-timezone')
const crypto = require('crypto')
const nbt = require('prismarine-nbt')

const BRIDGE_PREFIX = 'function:'

const io = new Server(3069)

io.on('connection', (socket) => {
    let functions

    let proxy

    const handler = {
        get (target, prop) {
            if (!target[prop]) throw new Error(`Function "${prop}" not available`)

            return (...args) => target[prop](...args)
        }
    }

    socket.on('setFunctions', (jsonArray) => {
        const parsed = JSON.parse(jsonArray)

        functions = {}
        
        for (const eachFuntion of parsed) {
            functions[eachFuntion] = (...args) => {
                socket.emit(BRIDGE_PREFIX + eachFuntion, ...args)

                return new Promise((resolve) => {
                    socket.once(`functionOutput:${eachFuntion}`, (message, parseJSON) => {
                        if (parseJSON) resolve(JSON.parse(message))
                        else resolve(message)
                    })
                })
            }
        }

        proxy = new Proxy(functions, handler)

        resetVM()
    })

    let vm
    function resetVM () {
        vm = new VM({
            timeout: 3000,
            sandbox: {
                get bridge () { return proxy },
                randomstring,
                ChatMessage,
                mc,
                moment,
                crypto,
                nbt
            }
        })
    }

    resetVM()

    socket.on('runCode', (transactionId, code) => {
        try {
            const output = vm.run(code)

            socket.emit('codeOutput', transactionId, false, util.inspect(output, { stylize }))
        } catch (e) {
            socket.emit('codeOutput', transactionId, true, e.toString())
        }
    })

    socket.on('reset', resetVM)
})

process.on('uncaughtException', (e) => {
    console.log(`Caught an uncaught exception!\n${e.stack}`)
})