How to identify for which user the stripe webhook route has been called?

Question

I am trying to implement a stripe subscription to my web app. I am using the stripe checkout session for this purpose.

I followed the stripe documentation https://stripe.com/docs/billing/subscriptions/build-subscriptions?ui=checkout

Whenever the checkout is completed checkout.session.completed event is fired. During this event I want to set subscriptionStatus from false to true in my database. But I am unable to identify for which user the /webhooks route has been called.

Here is my code:

export const postStripeWebhook = async (req: ExtendedRequest, res: Response) => {
    let data;
    let eventType;
    let event = req.body;
    const webhookSecret = "web hook secret provided by stripe";
    if (webhookSecret) {
        let signature = req.headers["stripe-signature"];

        try {
            event = stripe.webhooks.constructEvent(req.body, signature , webhookSecret);
        } catch (err) {
            console.log(`⚠️  Webhook signature verification failed.`);  //This part is throwing the error
            return res.sendStatus(400);
        }
        
        data = event.data;
        eventType = event.type;
    } else {
       
       
        data = req.body.data;
        eventType = req.body.type;
    }
    let subscription;

    switch (eventType) {
         
       case checkout.session.completed:
       
           //Logic to update subscriptionStatus of the user in the database 

       break;


       //other events are handles




    }

    res.sendStatus(200);
};

Please guide me on how to identify the user.

Answer 1

Under subscription mode, customer ID can be found under customer parameter in checkout.session.completed event. You can then use Customer Retrieval API to find the customer information.

Alternatively, you can create a Customer first, then set it in customer parameter when creating a Checkout Session. This allows you to identify the user with customer parameter in checkout.session.completed event afterwards.