chore(express): Improve webhook verification DX (#6284)

Co-authored-by: Robert Soriano <[email protected]>

Author: PrashanthKumar0

.changeset/four-stingrays-cheat.md

@@ -0,0 +1,5 @@
+---
+"@clerk/express": patch
+---
+
+Make webhook verification work with both raw and parsed request bodies

packages/express/src/webhooks.ts

@@ -21,9 +21,8 @@ export * from '@clerk/backend/webhooks';
  * @example
  * ```typescript
  * import { verifyWebhook } from '@clerk/express/webhooks';
- * import express from 'express';
  *
- * app.post('/api/webhooks', express.raw({ type: 'application/json' }), async (req, res) => {
+ * app.post('/api/webhooks', async (req, res) => {
  *   try {
  *     const evt = await verifyWebhook(req);
  *     // handle event
@@ -40,8 +39,23 @@ export async function verifyWebhook(req: ExpressRequest, options?: VerifyWebhook
   const webRequest = incomingMessageToRequest(req);
   // Cloning instead of implementing the body inside incomingMessageToRequest
   // to make it more predictable
+  // we must pass in body as string not as an Object or Buffer
+  let serializedBody: string;
+  if (typeof req.body === 'string') {
+    serializedBody = req.body;
+  } else if (Buffer.isBuffer(req.body)) {
+    serializedBody = req.body.toString('utf8');
+  } else if (req.body === undefined || req.body === null) {
+    serializedBody = '';
+  } else {
+    try {
+      serializedBody = JSON.stringify(req.body);
+    } catch (error) {
+      throw new Error(`Failed to serialize request body: ${error instanceof Error ? error.message : 'Unknown error'}`);
+    }
+  }
   const clonedRequest = new Request(webRequest, {
-    body: req.body,
+    body: serializedBody,
   });
   return verifyWebhookBase(clonedRequest, options);
 }