Fix missing function when IPN parameters are invalid

CRM/Core/Payment/StripeIPN.php

@@ -103,15 +103,15 @@ class CRM_Core_Payment_StripeIPN extends CRM_Core_Payment_BaseIPN {
    * @param array $parameters
    */
   public function setInputParameters($parameters) {
-    if (!is_object($parameters)) {
-      $this->exception('Invalid input parameters');
-    }
-
     // Determine the proper Stripe Processor ID so we can get the secret key
     // and initialize Stripe.
     $this->getPaymentProcessor();
     $this->_paymentProcessor->setAPIParams();
 
+    if (!is_object($parameters)) {
+      $this->exception('Invalid input parameters');
+    }
+
     // Now re-retrieve the data from Stripe to ensure it's legit.
     // Special case if this is the test webhook
     if (substr($parameters->id, -15, 15) === '_00000000000000') {