fix: return a 500 code on error in wh handler

Author: cabljac

firestore-stripe-payments/CHANGELOG.md

@@ -8,6 +8,8 @@
 
 [docs] - update references from @stripe to @invertase in docs
 
+[fix] - provide a 500 code to Stripe in the webhook handler response when appropriate
+
 ## Version 0.3.10 - 2025-03-24
 
 [fix] - upgrade resources to node 20

firestore-stripe-payments/functions/__tests__/tests/unit/handlers/webhook-events.test.ts

@@ -0,0 +1,79 @@
+import * as logs from '../../../../src/logs';
+import { handleWebhookEvents } from '../../../../src/handlers/webhook-events';
+import * as httpMocks from 'node-mocks-http';
+
+// Firebase functions will add rawBody to the request object before it reaches the handler
+declare module 'express' {
+  interface Request {
+    rawBody: Buffer;
+  }
+}
+
+jest.mock('../../../../src/logs', () => ({
+  startWebhookEventProcessing: jest.fn(),
+  webhookHandlerError: jest.fn(),
+  webhookHandlerSucceeded: jest.fn(),
+  badWebhookSecret: jest.fn(),
+}));
+
+jest.mock('../../../../src/config', () => ({
+  stripeWebhookSecret: 'test-webhook-secret',
+  customersCollectionPath: 'customers',
+  stripe: {
+    webhooks: {
+      constructEvent: jest.fn(),
+    },
+    paymentIntents: {
+      retrieve: jest.fn(),
+    },
+  },
+  eventChannel: null,
+}));
+
+jest.mock('firebase-admin', () => ({
+  initializeApp: jest.fn(),
+  firestore: jest.fn(() => {
+    throw new Error('Firestore operation failed');
+  }),
+}));
+
+describe('Webhook Events Handler', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+
+    const config = require('../../../../src/config');
+    config.stripe.webhooks.constructEvent.mockReturnValue({
+      id: 'evt_123',
+      type: 'product.created',
+      data: {
+        object: { id: 'prod_123' },
+      },
+    });
+  });
+
+  it('should return 500 status when webhook handler fails', async () => {
+    const mockRequest = httpMocks.createRequest({
+      rawBody: Buffer.from('test-body'),
+      headers: {
+        'stripe-signature': 'test-signature',
+      },
+    });
+
+    const mockResponse = httpMocks.createResponse();
+
+    await handleWebhookEvents(mockRequest, mockResponse);
+
+    expect(logs.webhookHandlerError).toHaveBeenCalledWith(
+      expect.any(Error),
+      'evt_123',
+      'product.created'
+    );
+
+    expect(mockResponse.statusCode).toBe(500);
+
+    const responseData = JSON.parse(mockResponse._getData());
+    expect(responseData).toEqual({
+      error: 'Webhook handler failed. View function logs in Firebase.',
+    });
+  });
+});

firestore-stripe-payments/functions/package-lock.json

@@ -35,6 +35,7 @@
     "firebase-functions-test": "^3.4.1",
     "jest": "^29.7.0",
     "mocked-env": "^1.3.5",
+    "node-mocks-http": "^1.17.2",
     "playwright": "^1.52.0",
     "rimraf": "^6.0.1",
     "ts-jest": "^29.3.4",

firestore-stripe-payments/functions/package.json

@@ -31,7 +31,7 @@ import {
 
 export const handleWebhookEvents = async (
   req: functions.https.Request,
-  resp
+  resp: functions.Response
 ) => {
   const relevantEvents = new Set([
     'product.created',
@@ -177,7 +177,7 @@ export const handleWebhookEvents = async (
       logs.webhookHandlerSucceeded(event.id, event.type);
     } catch (error) {
       logs.webhookHandlerError(error, event.id, event.type);
-      resp.json({
+      resp.status(500).json({
         error: 'Webhook handler failed. View function logs in Firebase.',
       });
       return;