trigger webhook without payment execute? - php

Question

I'm building paypal subscription system and i'm using web-hooks for notifying system on subscription created, active, etc.
However, it's required that user must return to success url and site execute $agreement->execute($token, $apiContext)); to make it work.
Let's say for some reason user never get back to return url then you will never execute payment and user will never get their subscription.
I've looked around on paypal documentation and couldn't find any solution.
Here's my code:
Subscribe.php:
$agreement = new Agreement();
$agreement->setName('Basic Plan')
->setDescription('Some info')
->setStartDate($date);
$plan = new Plan();
$plan->setId('PLAN_ID');
$agreement->setPlan($plan);
// Add Payer
$payer = new Payer();
$payer->setPaymentMethod('paypal');
$agreement->setPayer($payer);
// Add Shipping Address
$shippingAddress = new ShippingAddress();
$shippingAddress->setLine1('111 First Street')
->setCity('Saratoga')
->setState('CA')
->setPostalCode('95070')
->setCountryCode('US');
$agreement->setShippingAddress($shippingAddress);
// ### Create Agreement
try {
$agreement = $agreement->create($apiContext);
$agreement->getApprovalLink()
// method
$approvalUrl = $agreement->getApprovalLink();
redirect($approvalUrl);
} catch (Exception $ex) {
print_r($ex->getData());
}
index.php
if (isset($_GET['status']) && $_GET['status'] == 'success') {
$token = $_GET['token'];
$agreement = new \PayPal\Api\Agreement();
try {
// ## Execute Agreement
// Execute the agreement by passing in the token
echo "<pre>";
print_r($agreement->execute($token, $apiContext));
} catch (Exception $ex) {
exit(1);
}
} else {
echo "User Cancelled the Approval";
}