first commit

modules/paynow/vendor/pay-now/paynow-php-sdk/src/Paynow/Notification.php

@@ -0,0 +1,72 @@
+<?php
+
+namespace Paynow;
+
+use InvalidArgumentException;
+use Paynow\Exception\SignatureVerificationException;
+use Paynow\Util\SignatureCalculator;
+
+class Notification
+{
+    /**
+     * @param $signatureKey
+     * @param $payload
+     * @param $headers
+     * @throws SignatureVerificationException
+     */
+    public function __construct($signatureKey, $payload = null, ?array $headers = null)
+    {
+        if (! $payload) {
+            throw new InvalidArgumentException('No payload has been provided');
+        }
+
+        if (! $headers) {
+            throw new InvalidArgumentException('No headers have been provided');
+        }
+
+        $this->verify($signatureKey, $payload, $headers);
+    }
+
+    /**
+     * Verify payload Signature
+     *
+     * @param string $signatureKey
+     * @param string $data
+     * @param array $headers
+     * @throws SignatureVerificationException
+     * @return bool
+     */
+    private function verify(string $signatureKey, string $data, array $headers)
+    {
+        $calculatedSignature = (string)new SignatureCalculator($signatureKey, $data);
+        if ($calculatedSignature !== $this->getPayloadSignature($headers)) {
+            throw new SignatureVerificationException('Signature mismatched for payload');
+        }
+
+        return true;
+    }
+
+    /**
+     * Retrieve Signature from payload
+     *
+     * @param array $headers
+     * @throws SignatureVerificationException
+     * @return string
+     */
+    private function getPayloadSignature(array $headers)
+    {
+        if (isset($headers['Signature']) && $headers['Signature']) {
+            $signature = $headers['Signature'];
+        }
+
+        if (isset($headers['signature']) && $headers['signature']) {
+            $signature = $headers['signature'];
+        }
+
+        if (empty($signature)) {
+            throw new SignatureVerificationException('No signature was found for payload');
+        }
+
+        return $signature;
+    }
+}