Checkout flow: how should I process a new order? - node.js

Question

I'm trying to build an App which allows the customer to download a custom document after his order (so, the product I'm selling it's a digital custom document in pdf).
I'm trying to build that using React for the frontend, Node and Express for the backend, and PayPal Express Checkout (full-stack implementation) as payment.
What is not clear to me is what steps I should take to process an order.
I'm a this point:
Once customer clicks on PayPal button on client side it starts a call on http://localhost/api/paypal/orders endpoint which create the order on the Paypal side and return the PayPal order ID (e.g. id12345)
After the customer approves the payment on the PayPal popup, the client starts a call on http://localhost/api/paypal/orders/id12345/capture endpoint
then? What other endpoints should I crete on the server and what they should return? Maybe... 1 for save the actual store order on my MongoDB and the transaction details, 1 for create the invoice for the order, 1 for allowing the product download ???
Could you please clarify what steps I need to take, what are the endpoints I should create, and what each endpoints should return?
Maybe something like this?

Answer 1

You're trying to do too many things in too many routes. just create a route called something like process-order then you could have an async controller of that route which would contain separate functions for
Storing the order details in mongodb.
Create an invoice
Send a token that allows access to download page.
first , just await the function to complete then call the next.
exports.processOrder = async (req, res, next) => {
try {
const newOrder = await Order.create({
order: req.params.id,
details: req.body.details
})
const createInvoice = () => {
return newOrder._id;
}
const invoice = createInvoice();
const token = jwt.sign(
{
invoiceId = newOrder._id,
},
process.env.JWT_SECRET,
{
expiresIn: '24h'
}
);
return res.status(200).json({status: 'success', message: 'you have 24 hours to download your digital goods', token})
} catch (error) {
res.status(500).send(error)
}
}
This is a very basic idea, but basically store all of your info in one controller, then send a token with the id of the invoice, then when they go to download the book you would have a route where you verify the token. If it succeeds then the book is sent. like this:
app.use(
'/book-download',
expressJwt({ secret: process.env.JWT_SECRET, algorithms: ['HS256'] })
);
app.get('/book-download/success', async (req, res) => {
try{
const invoiceId = req.user.invoiceId;
const invoice = await Invoice.find({_id: invoiceId})
if (invoice) {
return res.status(200).json({status: 'success', message: 'congratulations on your new download', data: {E-book})
} else {
return.res.status(404).json({status: 'fail', message: 'could not find an invoice with that ID'})
} catch (error) {
return res.send(error)
}
});
You can choose to send the pdf via express, or you can allow them to enter a certain part of the website if the return is valid. There you go, that's an idea.

Answer 2

In Express check out, you need to define success / cancel handler
Ref here : https://www.section.io/engineering-education/nodejs-paypal-checkout/
In the success handler, based on the returned URI => you will get a Payer ID and payment ID. Based on that retrieve the transactio information (that internally contains yours order ID). Update your Order id as scucess / cancelled based on the paypal response.
app.get('/success', (req, res) => {
const payerId = req.query.PayerID;
const paymentId = req.query.paymentId;
const execute_payment_json = {
"payer_id": payerId,
"transactions": [{
"amount": {
"currency": "USD",
"total": "25.00"
}
}]
};
// Obtains the transaction details from paypal
paypal.payment.execute(paymentId, execute_payment_json, function (error, payment) {
//When error occurs when due to non-existent transaction, throw an error else log the transaction details in the console then send a Success string reposponse to the user.
if (error) {
console.log(error.response);
throw error;
} else {
console.log(JSON.stringify(payment));
res.send('Success');
}
});
});