PHP

<?php
use OrsunPay\Client;
use Nyholm\Psr7\Factory\Psr17Factory;

$factory = new Psr17Factory();
$client = new Client(
    apiKey: getenv('ORSUNPAY_API_KEY'),
    merchantId: getenv('ORSUNPAY_MERCHANT_ID'),
    baseUrl: getenv('ORSUNPAY_API_BASE_URL'),
    httpClient: new GuzzleHttp\Client(['timeout' => 30, 'connect_timeout' => 5, 'allow_redirects' => false]),
    requestFactory: $factory,
    streamFactory: $factory,
);
$transaction = $client->payments()->retrieveByOrderId($orderId)->data->transaction;

<?php
use OrsunPay\SignatureVerificationException;
use OrsunPay\Webhook;

$rawBody = file_get_contents('php://input');            // exact bytes, before any decoding
$header = $_SERVER['HTTP_ORSUNPAY_SIGNATURE'] ?? null;  // a single header value

try {
    $event = Webhook::constructEvent($rawBody, $header, [getenv('ORSUNPAY_WEBHOOK_SECRET')]);
} catch (SignatureVerificationException $e) {
    http_response_code(400);
    exit;
}

$eventId = $event->id();     // deduplicate on this
$eventType = $event->type(); // for example "transaction.updated"

<?php
use OrsunPay\InvalidResponseException;
use OrsunPay\ResponseDecoder;

try {
    $payment = (new ResponseDecoder())->decodePaymentResponse($responseBody);
} catch (InvalidResponseException $e) {
    // treat as an unexpected response; do not retry automatically
}