Listening to Webhooks

Assigning a LemonSqueezy Customer to a User

So... our site has users, and LemonSqueezy has customers... but as far as our code knows, they’re total strangers to each other. To build any meaningful integration - like fetching a user’s orders, debugging issues, or just having a smoother support experience when customers contact us about their orders - we need to connect them. More specifically, we want to store the LemonSqueezy customer ID on the corresponding User entity.

But here's a twist: When someone finishes checking out, LemonSqueezy creates a "customer" for us behind the scenes. You can’t pre-create a customer ID or pass an existing one during checkout. Nope! LemonSqueezy assigns one based on the email address they entered and whether they're logged into their LemonSqueezy account.

Webhooks

So... how can we grab that customer ID and link it to our user? Manually? Well, yes... but who wants to do that? Not me. Let's automate it instead, using some handy dandy webhooks.

We can send some metadata when the Checkout's created - like the user’s ID from our system - and when we receive the webhook (more on that in a second), we'll read that metadata, look up the proper user in our database, and stash that customer ID with it.

If you said "Wait... Can't we get the Customer ID right after they check out too?" that's correct! LemonSqueezy also dispatches a checkout:complete JavaScript event upon checkout that includes the Customer ID, which could be awesome for local development when you don’t want to configure webhook tunnels.

So... let’s do both!

Symfony Webhook Component

Since webhooks are a flexible, robust solution for production, let's start there. Over on the LemonSqueezy homepage, go to "Resources", choose "Help docs", and way down here in the "Webhooks" section, click on "Event types".

If we scroll a bit... I only see a few events dealing with orders. For our purposes, it looks like we'll need this order_created event - that should give us the order data we're looking for. If we click on it, and scroll down... yep! This returns customer_id! Nice!

Now, we could create a WebhookController to handle this ourselves, but Symfony’s got our back and recently released a new Webhook component that can help us handle this even better! Let's try it out! At your terminal, install it with:

composer require webhook

This gives us some much-needed dependencies. MakerBundle also has a command to help us get started. Run:

bin/console make:webhook

We'll call this lemon-squeezy. For the matcher, let's choose: PathRequestMatcher, which is option 6, and then MethodRequestMatcher - option 5. And since LemonSqueezy sends us data in JSON format, also select 4 - IsJsonRequestMatcher. Hit enter one more time, and... nice! This generated a parser and a consumer - more on those in a moment - and it also created a new endpoint. If we run:

bin/console debug:router | grep webhook

... there it is - our new /webhook/{type} URL! The {type} should be the lemon-squeezy webhook name we set earlier. This is a specific URL that'll handle LemonSqueezy webhooks. If we open that in the browser... yep! It throws a RejectWebhookException:

Request does not match.

Let's configure that! Copy this URL and, back on the LemonSqueezy dashboard, in "Settings", "Webhooks", click on the plus sign to edit the webhook. In the "Callback URL" field, paste the URL we copied a moment ago. But... hm... you may have already spotted the problem here. This URL isn't public, so LemonSqueezy's unable to hit our localhost.

We need to set up our webhooks properly using a tool like Ngrok, so LemonSqueezy can actually talk to our local machine. That's next.