push.js

var request = require('request');

// app below needs to be a Connect/Express app.

// Subscribing: use https://push.superfeedr.com/ to use Superfeedr (works with any feed!) 
function subscribe(url, conf, cb) {
  var hub = conf.hub;
  var params = {
    method: 'POST',
    uri: hub,
    auth: {
      'user': 'username',
      'pass': 'password',
    }, // Only required if you use Superfeedr as your default hub
    headers: {
      accept: 'application/json'
    }, // On required if you use Superfeedr as your default hub and if you want JSON normalization
    form: conf.form || {}
  }
  params.form['hub.mode'] = 'subscribe';
  params.form['hub.topic'] = url;
  params.form['hub.verify'] = 'sync'; // Only required if you use Superfeedr as your default hub
  params.form['hub.callback'] = base + '/push/' + encodeURIComponent(url);

  request(params, function(error, response, body) {
    if(response.statusCode === 204) {
      console.log('Subscribed to', url);
      cb();
    }
    else if(response.statusCode === 204) {
      console.log('Will verify intent subscription to', url);
      cb();
    }
    else {
      console.error(response.statusCode)
      console.error(body);
    }
  })
}

// Verification of intent. Not required when using https://push.superfeedr.com/
// You probably want to customiaz this to echo the challenge *only if* you really want to subscribe to the
// request.query['hub.topic']. Also, keep track of request.query['hub.lease_seconds'] because it indicates when/if
// you subscription will expire.
app.get('/push/:feed', function(request, response) {
  response.send(request.query['hub.challenge']);
});

//
app.post('/push/:feed', function(request, response) {
  // Do something with the body (needs to get it raw)
  response.send('Thx');
});