Js-ipfs server hangs for multiple queries

I’ve been implementing a simple web service to upload, encrypt and send files to ipfs.
It works nicely the first time but the second time the server hangs.
I’ve been trying and trying without success. Guess I don’t understand what happens to the ipfs node once the request ends and another one arrives, and how to access the initially spawned node, check for its existence etc. I have no understanding if the files I add are persisted locally.
Could someone please point to relevant documentation? Thanks!

var express = require('express');
var formidable = require('formidable');
var fs = require('fs');
// key not synched on git
var key = fs.readFileSync('./selfCert.key');
var cert = fs.readFileSync('./selfCert.crt')
var https = require('https');
var http = require('http');
var fs = require('fs')
var crypto = require('crypto');
var series = require('async/series')  
var IPFS = require('ipfs')
var https_options = { 
        key: key,
        cert: cert
var PORT = 443;
var HOST = '';
// Nodejs encryption of buffers
var privateKey = new Buffer('my secret');
var aes = crypto.createCipher('aes-256-cbc', privateKey);
https.createServer(https_options, function (req, res) {
        if (req.url == '/fileupload' && req.method == 'POST') {
                var form = new formidable.IncomingForm();
                // form parsing
                form.parse(req, function (err, fields, files) {
                        // Move to upload directory
                        var oldpath = files.filetoupload.path;
                        var newpath = '/home/davidweisss/DNA-IDstorage/uploads/' + files.filetoupload.name;
                        fs.rename(oldpath, newpath, function (err) {
                                if (err) throw err;
                        // create read stream to encrypt and send to ipfs
                        var rstream = fs.createReadStream(newpath);
                        // Upload to IPFS
                        // Create the File to add, a file consists of a path + content. More details on
                        // https://github.com/ipfs/interface-ipfs-core/tree/master/API/files
                        // asynchronous server startup and upload
                        const ipfsNode = new IPFS()
                        console.log('New IPFS node spawned')
                        let fileMultihash
                                        // 1. load ipfs server
                                        (cb) => ipfsNode.on('ready', cb),
                                        // 2. After loading ipfs 
                                        (cb) => ipfsNode.files.add({
                                                path: 'private_data_if_no_permission_destroy.encr',
                                                content: rstream.pipe(aes)
                                                // When file loaded
                                                (err, result) => {
                                                        if (err) { return cb(err) }
                                                        console.log('\nAdded file:', result[0].path, result[0].hash)
                                                        fileMultihash = result[0].hash
                                                        var b = 
                                                        '<h1> Your information is now encrypted in the interplanetary file system</h1>'
                                                        +'<h2>Your data is immortalized, and encrypted <a href="https://ipfs.io/ipfs/'+ fileMultihash +'">here</a>. This is the Multi hash of your file:'+fileMultihash+'</h2>'
                                                        +'<h2> Only you have its password. If shared with this location, it gives access to your data. Share wisely.</h2>';
                                                        console.log("We got here.")
        else {
                // Upload form
                res.writeHead(200, {'Content-Type': 'text/html'});
                res.write('<h1> Store and send encrypted content to anyone</h1>');
                res.write('<h2>Encrypt and store in always-available, non-erasable peer-to-peer storage <br> Access and share with keys on www.</h2>');
                res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
                res.write('<input type="file" name="filetoupload"><br>');
                res.write('<input type="submit">');
                res.write('<p>secure https server encrypting your info then uploading it to permanent peer to peer storage network (ipfs). <br> </br> Gives you a web adress (ipfs) and a password to decrypt your data</p>');
                res.write('<p>Only you, and whomever you share the key with, has access</p>');
                res.write('<p>* this service is used by https://dnavid.com through its API to upload personal DNA information while retaining control. <p>');
                return res.end();
}).listen(PORT, HOST);
// start server
//server = https.createServer(https_options, app).listen(PORT, HOST);
console.log('HTTPS Server listening on %s:%s', HOST, PORT);
// Redirect from http port 80 to https
http.createServer(function (req, res) {
        res.writeHead(301, { "Location": "https://" + req.headers['host'] + req.url });