Ros node template for nodejs

index.js

#!/usr/bin/env node

const rosnodejs = require('rosnodejs');
const { readFileSync, readdirSync } = require('fs');
const { readFile } = require('fs').promises;
const express = require('express');
const app = express();
const path = require('node:path'); 

let host = null
let port = null
let vel_topic = null
let apppath = null

function start_server() {
    
    app.get("/host", (req, res) =>      { res.send(host)      }) 
    app.get("/vel_topic", (req, res) => { res.send(vel_topic) }) 

    app.use(express.static(apppath));
    
    app.get('/', async (request, response) => {
        response.send( await readFile("index.html", 'utf8'));
    });
    
    app.listen(process.env.PORT || 5000, () => {
        console.log(`NODE: App available on http://localhost:${5000}`)
    });
}


rosnodejs.initNode('http_serve', {node: {anonymous: true}})
    .then((nh) => {
        nh.getParam("~host").then((val) =>      {console.log(val);  host = val                     }).catch(console.log) 
        nh.getParam("~port").then((val) =>      {console.log(val);  port = val                     }).catch(console.log) 
        nh.getParam("~vel_topic").then((val) => {console.log(val);  vel_topic = val                }).catch(console.log) 
        nh.getParam("~apppath").then((val) =>   {console.log(val);  apppath = val; start_server()  }).catch(console.log) 
    });