How to reference a paypal webhook to a user? - paypal

Question

I'm trying to figure out the best way to associate the webhook to a user of the webapp.
Upon a paypal transaction I receive the webhook from paypal
but it doesn't have a reliable reference that I can use
to associate with the user in the app.
My solution would be to:
On the onApprove function use javascript code to submit a form with the subscriptionID
hidden on an input and send it to the server.
After receiving the subscriptionID on the server, create the webhook database entry with the subscriptionID field of the user that made the transaction.
And when I receive the webhook from paypal I can reference the user through the
subcriptionID.
Anyone around went through this one with a better option?
I was thinking if there is a way to insert the userID of the webapp in the paypal webhook.
Would be more clean.
Havent' found anything tho.
Here is the paypal webhook client call:
<script>
paypal.Buttons({
style: {
shape: 'pill',
color: 'gold',
layout: 'vertical',
label: 'subscribe'
},
createSubscription: function(data, actions) {
return actions.subscription.create({
/* Creates the subscription */
plan_id: '************************'
});
},
onApprove: function(data, actions) {
alert(data.subscriptionID); // You can add optional success message for the subscriber here
}
}).render('#paypal-button-container-******************'); // Renders the PayPal button
</script>
Thanks

Answer 1

When you create the subscription, pass a unique custom_id

Answer 2

thanks Preston. This is defenitely the best option. I was having trouble because I was adding a new field with a random name to associate to the userID of the app. It turns out that you really need to use the custom_id key in order to receive it in the webhook calls.
Final solution was the following:
<script>
paypal.Buttons({
style: {
shape: 'pill',
color: 'gold',
layout: 'vertical',
label: 'subscribe'
},
createSubscription: function(data, actions) {
return actions.subscription.create({
/* Creates the subscription */
plan_id: '************************',
custom_id: 'appUserID'
});
},
onApprove: function(data, actions) {
alert(data.subscriptionID); // You can add optional success message for the subscriber here
}
}).render('#paypal-button-container-******************'); // Renders the PayPal button
</script>
Then the custom_id field will be available in all of the webhook calls. Perfect!