PayPal v2 Orders API - difference between OrdersGetRequest and OrdersCaptureRequest - spring

Question

I'm using checkout-sdk with angular and spring boot. Here is the code I have on the angular side
paypal
.Buttons({
style: {
color: 'blue',
shape: 'pill',
label: 'pay',
height: 40
},
createOrder: (data, actions) => {
return actions.order.create({
purchase_units: [
{
description: 'Order id: '+this.order.id,
amount: {
currency_code: 'EUR',
value: this.order.totalPrice
}
}
]
});
},
onApprove: async (data, actions) => {
const order = await actions.order.capture();
this.paidFor = true;
this.checkoutPaypal(this.id,order.id)
},
onError: err => {
}
})
.render(this.paypalElement.nativeElement);
This is function used to retrieve payment, and save details to database..
public String checkoutPaypal(Integer id, String orderId) {
OrdersCaptureRequest request = new OrdersCaptureRequest(orderId);
request.requestBody(buildRequestBody());
HttpResponse<com.paypal.orders.Order> response;
try {
response = payPalClient.client().execute(request);
} catch (IOException e) {
throw new ResponseStatusException(HttpStatus.INTERNAL_SERVER_ERROR, e.getMessage());
}
for (PurchaseUnit purchaseUnit : response.result().purchaseUnits()) {
purchaseUnit.amountWithBreakdown();
for (Capture capture : purchaseUnit.payments().captures()) {
if (capture.status().equals("COMPLETED")) {
Order order = orderRepository.findById(id).orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND, "Not found!"));
order.setOrderState(OrderState.PAID);
order.setPaymentDetails("Charge id: " + capture.id() + "; Status: " + capture.status() + "; Time paid: " + capture.createTime() + " GMT");
order.addOrderStateChange(OrderState.PAID, false);
sendEmail(order, " paid successfully!", "Thanks for your purchase!<br>We will work as hard as we can, to deliver the order to you, as soon as possible!");
orderRepository.save(order);
}
}
}
return "Successfully paid!";
}
Which worked few days ago.. But now I'm getting this error
{"name":"UNPROCESSABLE_ENTITY","details":[{"issue":"ORDER_ALREADY_CAPTURED","description":"Order already captured.If 'intent=CAPTURE' only one capture per order is allowed."}],"message":"The requested action could not be performed, semantically incorrect, or failed business validation.","debug_id":"f058cb447ccbb","links":[{"href":"https://developer.paypal.com/docs/api/orders/v2/#error-ORDER_ALREADY_CAPTURED","rel":"information_link","method":"GET"}]}
But after replacing
OrdersCaptureRequest request = new OrdersCaptureRequest(orderId);
request.requestBody(buildRequestBody());
HttpResponse<com.paypal.orders.Order> response;
with
OrdersGetRequest request = new OrdersGetRequest(orderId);
HttpResponse<com.paypal.orders.Order> response;
It works as it should.
So my question is, what is the difference between
https://developer.paypal.com/docs/checkout/reference/server-integration/capture-transaction/
and
https://developer.paypal.com/docs/checkout/reference/server-integration/get-transaction/ ?

Answer 1

One is to get the status of the order, the other is to capture the order.
Capturing should not be done once you have called actions.order.capture() on the client side, and will always return an error in such a case. It may also also return an error when the order has been created on the client side (actions.order.create())
A correct server-based integration uses neither actions.order.create() nor actions.order.capture() on the client side. It is very important not to do so, as transactions will be created without your server receiving any immediate direct response from PayPal.
Instead, create two routes on your server, one for 'Create Order' and one for 'Capture Order' as documented here. These routes should return JSON data. Before returning data, the capture route should check for success and act accordingly to send an email or whatever other business operation you need.
The approval flow to pair with the above two routes is https://developer.paypal.com/demo/checkout/#/pattern/server