HTTP retry

server.js

const express = require('express');

console.log(process.version);

const app = express();

app.get('/hello', (req, res) => {
  console.log('HANDLING REQUEST');
  res.setHeader('content-type', 'application/json');
  res.flushHeaders(); // `flushHeaders` to prevent http client from retrying and therefore invoking this handler multiple times.
  res.destroy();
});

app.listen(9000, () => {
  console.log('Listening');
});

// https://blogs.oracle.com/ravello/beware-http-requests-automatic-retries

With POST, and without flushHeaders (request done using fetch in Chrome console) the browser does not repeat the request and HANDLING REQUEST is printed only once)