Node.JS static file web server, also provides CORSProxy, Http/Https proxy function. Put it in your path to fire up servers in any directory, takes an optional port argument. If provide second https port argument, it will also start https. For https to work, need to put key and cert file in the folder.

static_server.js

#!/usr/bin/env node

const { argv } = require('process');

/**
Static http server implemented with NodeJS. 

Features:

1. No external dependencies
2. Support http/https, with custom port.
3. Support CORSProxy function
4. Zero configuration, convension over configuration
5. Support gzip compression

Usage:
1. Static file directory

It will always serve the static files under current directory where the process is started.

2. Start http server with default port: (http on 80), it will server the static file under current directory
node static_server.js

3. Start http on 8080 and https on 8443, to support https, you need to put the key.pem and cert.pem under current directory
node static_server.js 8080 8443. 

To generate cert.pem: openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 10000 -nodes


4. To access it as CORSProxy:

https://host/https://www.somewebsite.com

or 

http://host/http://www.somewebsite.com

5. To bypass SSL certification check (when using proxy mode)
NODE_TLS_REJECT_UNAUTHORIZED=0 node static_server.js

*/

function findFirstArg() {
  for (let i; i < argv.length; i++) {
    if (argv[i].endsWith(__filename))
      return i;
  }
  return 1;  // default:  node static_server.js
}

let argIdx = findFirstArg();

console.log(`argIdx=${argIdx}, _fileName=${__filename}, argv=${argv}`)

const http = require('http'),
    https = require('https'),
    url = require('url'),
    Path = require('path'),
    fs = require('fs'),
    zlib = require('zlib'),
    port = process.argv[argIdx + 1] || 8888,
    httpsPort = process.argv[argIdx + 2] || 0;

console.log("Command Line Format: node static_server.js [port] [httpsPort]");
http.createServer(serve).listen(parseInt(port, 10));
console.log(`Static file server running at\n  => http://localhost:${port}`);

if (httpsPort){
  var opt;
  try {
    opt = {
      key: fs.readFileSync("key.pem"),
      cert: fs.readFileSync("cert.pem"),
    };
  } catch(e) {
    console.log("Error start https: missing key.pem and cert.pem in current directory");
  }
  if (opt) {
    https.createServer(opt, serve).listen(parseInt(httpsPort, 10));
    console.log(`https at\n  => https://localhost:${httpsPort}`);
  }
}
console.log(`CTRL + C to shutdown`);

function serve(request, response) {
  try {
    const path = url.parse(request.url).pathname
    if (path.startsWith('/https://') || path.startsWith('/http://'))
      serveProxy(path, request, response);
    else
      serveLocalFile(path, request, response);
  } catch(e) {
    response.writeHead(500, {'Content-Type': 'text/plain'});
    response.write(`Error connect to remote server: exception=${error}\n`);
    response.end();
  }
}

function serveProxy(path, request, response) {
  const uri = url.parse(path.substring(1));
  const isHttps = uri.protocol === 'https:';
  const opt = {
    hostname: uri.hostname,
    port: uri.port || (isHttps ? 443 : 80),
    path: uri.path,
    method: request.method,
    headers: request.headers,
  };
  delete opt.headers.host;

  const ht =  isHttps ? https : http;
  const proxy = ht.request(opt, (res) => {
    const headers = Object.assign(res.headers, {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Method': request.headers['access-control-request-method'] || '*',  // TODO: case insensitive
      'Access-Control-Allow-Headers': request.headers['access-control-request-headers'] || '*',
    });
    response.writeHead(res.statusCode, headers);
    res.on('data', (data) => {
      response.write(data);
    });
    res.on('end', () => {
      response.end()
    });
  });

  proxy.on('error', (error) => {
    response.writeHead(500, {'Content-Type': 'text/plain'});
    response.write(`Error connect to remote server: exception=${error}\n`);
    response.end();
  });
  request.on('data', (data) => {
    proxy.write(data)
  });
  request.on('end', () => {
    proxy.end();
  });
}

function serveLocalFile(path, request, response) {
  var filename = Path.join(process.cwd(), path);

  fs.exists(filename, function(exists) {
    if(!exists || filename.endsWith('.pem')) {
      response.writeHead(404, {'Content-Type': 'text/plain'});
      response.write('404 Not Found\n');
      response.end();
      return;
    }

    if (fs.statSync(filename).isDirectory()) {
      serveLocalFile(path + '/index.html', request, response);
      return;
    }

    response.writeHead(200, { 'Access-Control-Allow-Origin': '*' });
    var raw = fs.createReadStream(filename);
    
    var acceptEncoding = request.headers['accept-encoding'] || '';        
    if (acceptEncoding.match(/\bdeflate\b/)) {
      response.writeHead(200, { 'content-encoding': 'deflate' });
      raw.pipe(zlib.createDeflate()).pipe(response);
    } else if (acceptEncoding.match(/\bgzip\b/)) {
      response.writeHead(200, { 'content-encoding': 'gzip' });
      raw.pipe(zlib.createGzip()).pipe(response);
    } else {
      response.writeHead(200, {});
      raw.pipe(response);
    }
    
    // fs.readFile(filename, 'binary', function(err, file) {
    //   if(err) {
    //     response.writeHead(500, {'Content-Type': 'text/plain'});
    //     response.write(err + '\n');
    //     response.end();
    //     return;
    //   }

    //   response.writeHead(200, { 'Access-Control-Allow-Origin': '*' });
    //   response.write(file, 'binary');
    //   response.end();
    // });
  });
}

make the js file executable

Would you be willing to port this to run via nanohttpd in Java? https://github.com/NanoHttpd/nanohttpd

I would but my experience with Java isn't good enough to tackle this.

Fix few bugs related to proxy to an https server with custom port number
Added a usage example to by pass ssl certificate check.