Can I process a webhook in the app.post method Express JS?

[w1am]

There are three components that allows webhooks to work in Shopify Apps.

A: Loading the handlers

Shopify.Webhooks.Registry.addHandler("APP_UNINSTALLED", {
  path: "/webhook/uninstall",
  webhookHandler: async (topic, shop, body) => {
    // I don't want to process it here. Instead, I want to do it in C directly.
    console.log(topic, shop, body);
  },
});

B: Register the webhook

const response = await Shopify.Webhooks.Registry.register({
  shop: shopSession.shop,
  accessToken: String(shopSession.accessToken),
  topic: "APP_UNINSTALLED",
  path: "/webhook/uninstall",
});

if (!response.APP_UNINSTALLED.success) {
  console.log(
    `Failed to register APP_UNINSTALLED webhook: ${response.result}`
  );
} else {
  console.log("webhook registered");
}

C: Process webhook

app.post("/webhook/uninstall", async (req, res) => {
  try {
    // I want to process the webhook here instead of doing it in A because I need to fetch some user information in the req object.
    await Shopify.Webhooks.Registry.process(req, res);
    console.log("Webhook processed, returned status code 200");
  } catch (error) {
    console.log(`Failed to process webhook: ${error}`);
    if (!res.headersSent) {
      res.status(500).send(error.message);
    }
  }
});

Is it possible to process the webhook in C instead of doing it in the callback function in A ? If the answer is no. How can I do it so that I can access the req or res object when a webhook is called.