PayPal Express Checkout, update database on successful payment - php

Question

Introduction
I´ve been looking at integrating a somewhat big project of mine with PayPal Express Checkout, and use that as the main system to handle payments on my site. Although their documentation is quite extensive, I really can´t find too good a place to start. Over the past few days, I´ve been presented with headache upon headache, in attempt to figure out how on Earth to integrate my site, as well as its database, with PayPal Express Checkout.
Summary
The JavaScript bit is pretty straight forward, and charging money using the client-side integration is extremely easy. But I also need a way to update fields in my database upon a payment going through (being successful), and from what I´ve understood so far, that can only be done by using the advanced server integration.
Problem
The problem, given the aforementioned reasons, is somehow managing to implement the advanced server integration solution, into my platform, in order to make way for changes in the database to occur upon a transaction being successful.
As mentioned before, the PayPal documentation is fairly extensive--problem is, I´ve never really went over using REST API´s, and it appears as though integrating what I´m after can only really be done using the PayPal REST API, to verify that the payment(s) have taken place.
Question
With all that being said, what I need help with is finding some place in all of this to start. I´m aware StackOverflow may not be the best place for a question like this, but it appears lots of people are having trouble with this exact question, and it´s an essential part of settings up any business on the web to get this to work.
Any pointers on where to start, or anything relating to the subject other than the PayPal documentation would be extremely helpful.

Answer 1

What follows is a minimal way to use Express Checkout with a server-side Payments REST API integration, including the associated code for client and server in JavaScript. I hope it helps.
You'll need to login to developer.paypal.com and create a REST API app. Your new app will be assigned a Client ID and Secret which you can use to request access tokens, which authorize your use of the PayPal REST API. The only app setting you need for what follows here is "Accept Payments". Sandbox accounts for testing are automatically created when you create an app.
Your (checkout) page loads PayPal's Express Checkout script, and a script you write renders a PayPal button:
// In your script:
paypal.Button.render({
env: 'sandbox', // Or 'production'.
commit: true, // Show 'Pay Now' button.
style: { // Style the button.
size: 'responsive',
color: 'silver',
shape: 'rect'
},
payment: function(data, actions) {
// See step 3.
},
onAuthorize: function(data, actions) {
// See step 7.
}
}, '#paypal-button');
Your customer clicks the rendered PayPal checkout button.
The payment function you define in the argument you give to paypal.Button.render() is called by PayPal's script, which sends a request to your server with your payload. Your payload contains (for example) cart contents and its associated data.
paypal.Button.render({
// ...
payment: function(data, actions) {
return paypal.request(
{
method: 'post',
url: '/your-api/create-payment',
json: {
order: items,
or: whatever
}
}
).then(
function(res) {
// Return the payment id received from your server.
return res.paymentId;
}
).catch(
function(err) {
// Oops, foobared.
}
);
},
// ...
}
Your server sends a request to api.sandbox.paypal.com, with your access token, to create a payment. When your server receives the newly created payment data from PayPal it (perhaps) persists the data on your server, but it must return the payment id to the client.
// HTTP request data for creating a payment.
{
method: 'post',
// Remove '.sandbox' below to use production endpoint.
url: 'https://api.sandbox.paypal.com/v1/payments/payment';
headers: {
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + 'your access token here'
},
data: {
// Allows immediate payments with PayPal and credit cards in
// the Express Checkout dialog.
intent: 'sale',
// I suppose these were required by other PayPal REST services,
// but they won't be used because, for Express Checkout, you
// handle the confirmation/cancellation flow yourself, on the
// client.
redirect_urls: {
return_url: 'https://...'
cancel_url: 'https://...'
},
payer: {
payment_method: 'paypal',
},
note_to_payer: 'Thanks, you\'re magnificently awesome!',
transactions: [{
amount: {
total: total, // Your computed total.
currency: 'USD',
details: {
subtotal: subtotal, // Your computed subtotal.
tax: tax, // Your computed tax.
shipping: shipping // Your computed shipping.
// Other parameters are available for your use.
}
},
item_list: {
items: [
{
name: 'shinny shirt of mithril mail',
description: 'shinny',
sku: '12345',
quantity: 1,
price: 1.00,
currency: 'USD'
}
],
// Some properties aren't required, like this one.
shipping_method: 'USPS'
},
description: 'Your PayPal payment for a shinny shirt of mithril mail.',
// Not required and can be added later by patching the
// payment: maybe you don't want to add an invoice to and
// order until the payment is approved.
invoice_number: 12345
}]
}
}
The payment function you provided then receives the payment id from your server and uses it as its return value.
// See return value in step 3.
And now the Express Checkout payment dialog pops up for your customer, who must login in and confirm the payment, create an account, or checkout with a credit/debit card.
After the customer confirms payment by clicking the Pay Now button in the Express Checkout dialog, the onAuthorize function you define in the argument you give to paypal.Button.render() is called by PayPal's script. You can use this function's actions parameter to get() payment information from PayPal, which you can use in a confirmation page, etc. Use its data parameter to get the payment id and payer id, which must be sent in a request to your server to execute the payment.
onAuthorize: function(data, actions) {
return actions.payment.get().then(function(paymentDetails) {
// Get at the payment details like this...
// paymentDetails.payer.payer_info.first_name;
// paymentDetails.payer.payer_info.shipping_address.city;
// paymentDetails.payer.payer_info.shipping_address.state;
var payload = {
paymentId: data.paymentID,
payerId: data.payerID
};
return paypal.request(
{
method: 'post',
url: '/your-api/execute-payment',
json: payload {
paymentId: data.paymentID,
payerId: data.payerID
}
}
).then(
function(res) {
// Gotten paid! Show confirmation page.
}
).catch(
function(err) {
// Dang it.
}
);
});
}
Your server receives the payment id and payer id from the client and makes another request to PayPal, this time to execute the payment. The transaction is complete if the execute request returns successfully. And now you can persist (or update) the payment data on your server.
// HTTP request data for executing a payment.
{
method: 'post',
// Remove '.sandbox' below to use production endpoint.
url: 'https://api.sandbox.paypal.com/v1/payments/payment/' + paymentId + '/execute/',
headers: {
'Content-Type': 'application/json',
'Authorization': 'Bearer ' + 'your access token here'
},
data: {
payer_id: payerId
}
}
The client's latest request to your server completes successfully and you show a confirmation page, optionally with payment info from step 7 or from your server.
As for a place to start, here's what I suggest:
Automate requesting and storing your access token on your server. You'll need to store it because PayPal rate-limits token requests. So, either automate keeping it fresh or request a new one whenever you need to. I believe they expire in eight or nine hours; in any case, the expires-in time is given to you with the token. https://developer.paypal.com/docs/api/overview/
Build the /your-api/create-payment server endpoint. Test it with requests from an API tool like Postman using your access token. When everything goes well your server will make a successfull call to PayPal to create a payment, and you can explore the data in the response. It doesn't matter that you don't plan to execute the payment...it's the sandbox after all. Then build in your server-side persistence (if you want) and return the payment id to the client.
Next, load the PayPal script and your checkout-button rendering script on your site, and see if the Express Checkout login appears when you click the checkout button. If an error occurs in the create-payment process you'll see an error rather than the Express Checkout login.
When your system is creating payments and you can log in at the Express Checkout dialog with your sandbox credentials, build the /your-api/execute-payment endpoint. When your server has a working execute-payment endpoint you should be able to log in with Express Checkout and use your sandbox buyer account to complete a payment.
If after all that you think you'll have a go, the docs you want to pay attention to are https://developer.paypal.com/docs/api/ > API Reference > Payments API > Payments. There are five sections: create, execute, show, update and list. Read them. It will help.