How can I set amount field to PayPal SDK - php

Question

I am working on PayPal express and want to send the amount field value to the server file (payment.php)
from the client-side script and also want to gets its value to the server-side file.
Here is client-side script
<script src="https://www.paypal.com/sdk/js?client-id=<client-id>"></script>
<script>
paypal.Buttons({
createOrder: function() {
return fetch('payment.php', {
method: 'post',
headers: {
'content-type': 'application/json'
},
}).then(function(res) {
return res.json();
}).then(function(data) {
return data.id;
});
},
onApprove: function(data, actions) {
// This function captures the funds from the transaction.
return actions.order.capture().then(function(details) {
// This function shows a transaction success message to your buyer.
window.location = "paypal-transaction-complete.php?&orderID="+data.orderID;
});
}
}).render('#paypal-button-container');
</script>
<div id="paypal-button-container"></div>
Here is the payment.php where I want to get the amount field value
<?php
namespace Sample\CaptureIntentExamples;
require __DIR__ . '/vendor/autoload.php';
//1. Import the PayPal SDK client that was created in `Set up Server-Side SDK`.
use Sample\PayPalClient;
use PayPalCheckoutSdk\Orders\OrdersCreateRequest;
require 'paypal-client.php';
class CreateOrder
{
public static function createOrder($debug=false)
{
$request = new OrdersCreateRequest();
$request->prefer('return=representation');
$request->body = self::buildRequestBody();
// 3. Call PayPal to set up a transaction
$client = PayPalClient::client();
$response = $client->execute($request);
echo json_encode($response->result, JSON_PRETTY_PRINT);
return $response;
}
private static function buildRequestBody()
{
return array(
'intent' => 'CAPTURE',
'application_context' =>
array(
'return_url' => 'https://example.com/return',
'cancel_url' => 'https://example.com/cancel'
),
'purchase_units' =>
array(
0 =>
array(
'amount' =>
array(
'currency_code' => 'USD',
'value' => '20.00'
)
)
)
);
}
}
if (!count(debug_backtrace()))
{
CreateOrder::createOrder(true);
}
?>
Please let me know how can I do that? Thanks!

Answer 1

With PHP the simplest way is going to be to use a GET string.
return fetch('payment.php?amount=' + document.getElementById('amount').value , {
^ You might want to validate or sanitize that input or URL encode the value, but for the most part it should work.
array(
'currency_code' => 'USD',
'value' => $_GET['amount']
)
It's not modern but that's PHP for you, parsing JSON is probably overkill.
You shouldn't be using actions.order.capture() when creating on the server, I'd be surprised if that even works. Implement a capture order route on your server, and use this JS sample that has proper error handling: https://developer.paypal.com/demo/checkout/#/pattern/server