server.js

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

const app = express();
const bodyParser = require('body-parser');

const fetch = require('node-fetch');
// const db = require('./queries')

const { seqrun, publication, summary, s3public, misc } = require('./routes');

const port = process.env.PORT || 5000;

app.use(bodyParser.json());
app.use(
  bodyParser.urlencoded({
    extended: true,
  })
);

app.use(express.static(path.join(__dirname, 'client/build')));

// app.get('/data', db.getData);
app.use('/api/v1/seqrun', seqrun);
app.use('/api/v1/publication', publication); // http://localhost:3000/visualization/c91952a9b48f32a8f26a.worker.js
app.use('/api/v1/summary', summary);
app.use('/api/v1/misc', misc);
app.use('/data', s3public);

WORKER_SCRIPTS = {}

const getWorkerScript = (req, res) => {
  /**
   * 1. Fetch the real worker.js file from http://target.wustl.edu/dli/eg/c91952a9b48f32a8f26a.worker.js
   * 2. Save the fetched contents in WORKER_SCRIPTS[hash], https://www.npmjs.com/package/node-fetch
   * 3. Return WORKER_SCRIPTS[hash], see res.sendFile docs or google "express send string as file"
   */
  if (WORKER_SCRIPTS[req.params.hash]) {
    res.type('.js');
    return res.send(WORKER_SCRIPTS[req.params.hash]);
  }

   fetch('http://target.wustl.edu/dli/eg/' + req.params.hash + '.worker.js')
      .then(res => res.text())
      .then(text => {
        WORKER_SCRIPTS = {
          [req.params.hash]: text,
        }
        res.type('.js');
        res.send(WORKER_SCRIPTS[req.params.hash]);
      });
};

// check express docs for how to do something like /{hash}.worker.js
app.get('/:path/:hash.worker.js', getWorkerScript)
app.get('/:hash.worker.js', getWorkerScript)

app.get('*', (req, res) => {
  res.sendFile(path.join(`${__dirname}/client/build/index.html`));
});

// console.log that your server is up and running
app.listen(port, () => console.log(`Listening on port ${port}`));