Webhook_backend.js

const express = require('express');

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

//Removed for sec reasons
const stripe = require('stripe')('sk_test_xxxxx');
const endpointSecret = 'whsec_xxxxx';

// set the port of our application
// process.env.PORT lets the port be set by Heroku
var port = process.env.PORT || 8080;


app.post('/', bodyParser.raw({type: 'application/json'}), (request, response) => {
    const sig = request.headers['stripe-signature'];
    let event;

    try {
        event = stripe.webhooks.constructEvent(request.body, sig, endpointSecret);
    } catch (err) {
        return response.status(400).send(`Webhook Error: ${err.message}`);
    }

    function handleCheckoutSession(uid) {
        // Here we are getting the session obj and we can process it to check for the things we need

        console.log("UID is " + uid);


    }

    // Handle the checkout.session.completed event
    if (event.type === 'checkout.session.completed') {
        const session = event.data.object;
      
      
      ------------------------------------------
      
        let uid = request.data.metadata.uid;
      
      THE METADATA IS UNDEFINED HERE
      ----------------------------------------

        // Fulfill the purchase...
        handleCheckoutSession(uid);
    }

    // Return a response to acknowledge receipt of the event
    response.json({received: true});
});

app.listen(port, function () {
    console.log('Our app is running on http://localhost:' + port);
});

module.exports = app;