The Open Event Webapp Generator has a pure HTML front end form, and Express based backend.

We needed an option where users can upload their own JSON files to create a schedule page for it.

On the HTML form that’s easy. As you can see here we simple add input tags with type=”file”

<input type="file" name="sponsorfile" id="sponsorfile">

In our express app, we need to use multer to be able to handle file uploads.

We create a middleware called uploadedFiles, and pass the middleware to the get() block

var express = require('express');
var multer = require('multer');
var app = express();

var upload = multer({dest: 'uploads/'});

var uploadedFiles = upload.fields([
  {name: 'speakerfile', maxCount: 1},
  {name: 'sessionfile', maxCount: 1},
  {name: 'trackfile', maxCount: 1},
  {name: 'sponsorfile', maxCount: 1},
  {name: 'eventfile', maxCount: 1},
  {name: 'locationfile', maxCount: 1}
]);'/live', uploadedFiles, function(req, res) {
         // req.files has the files
         // req.body has the POST body params

Now we can access the files inside req.files (that will have a path to the temporary location of the file, you’ll have to use some filesystem module to read the files), and the POST params in req.body