Serve Static Files on a Dynamic Route using Express

Okay. I found an example in the source code for Express' response object. This is a slightly modified version of that example.

app.get('/user/:uid/files/*', function(req, res){
    var uid = req.params.uid,
        path = req.params[0] ? req.params[0] : 'index.html';
    res.sendFile(path, {root: './public'});
});

It uses the res.sendFile method.

NOTE: security changes to sendFile require the use of the root option.

You can use res.sendfile or you could still utilize express.static:

const path = require('path');
const express = require('express');
const app = express();

// Dynamic path, but only match asset at specific segment.
app.use('/website/:foo/:bar/:asset', (req, res, next) => {
  req.url = req.params.asset; // <-- programmatically update url yourself
  express.static(__dirname + '/static')(req, res, next);
});         

// Or just the asset.
app.use('/website/*', (req, res, next) => {
  req.url = path.basename(req.originalUrl);
  express.static(__dirname + '/static')(req, res, next);
});

I use below code to serve the same static files requested by different urls:

server.use(express.static(__dirname + '/client/www'));
server.use('/en', express.static(__dirname + '/client/www'));
server.use('/zh', express.static(__dirname + '/client/www'));

Although this is not your case, it may help others who got here.