From 9d345a29b9a50cd472e4f5d42eaa4b2f4bd48364 Mon Sep 17 00:00:00 2001
From: Walter Moar <Walter.Moar@gov.bc.ca>
Date: Thu, 29 Feb 2024 07:57:09 -0800
Subject: [PATCH] test: FORMS-914 rate limiter unit tests (#1300)

* test: FORMS-914 rate limiter unit tests

* Undid unnecessary change

* switched rate limit strings to template literals

* changed if clause formatting for consistency

* tests missing async keyword
---
 .../forms/common/middleware/rateLimiter.js    |   4 +-
 .../common/middleware/rateLimiter.spec.js     | 144 ++++++++++++++++++
 2 files changed, 146 insertions(+), 2 deletions(-)
 create mode 100644 app/tests/unit/forms/common/middleware/rateLimiter.spec.js

diff --git a/app/src/forms/common/middleware/rateLimiter.js b/app/src/forms/common/middleware/rateLimiter.js
index ed673918b..b31d9ec69 100644
--- a/app/src/forms/common/middleware/rateLimiter.js
+++ b/app/src/forms/common/middleware/rateLimiter.js
@@ -7,8 +7,8 @@ const apiKeyRateLimiter = rateLimit({
 
   limit: config.get('server.rateLimit.public.max'),
 
-  // Skip Bearer token auth so that CHEFS app users are not limited.
-  skip: (req) => req.headers && req.headers.authorization && !req.headers.authorization.startsWith('Basic '),
+  // Skip everything except Basic auth so that CHEFS app users are not limited.
+  skip: (req) => !req.headers?.authorization || !req.headers.authorization.startsWith('Basic '),
 
   // Use the latest draft of the IETF standard for rate limiting headers.
   standardHeaders: 'draft-7',
diff --git a/app/tests/unit/forms/common/middleware/rateLimiter.spec.js b/app/tests/unit/forms/common/middleware/rateLimiter.spec.js
new file mode 100644
index 000000000..001daebfc
--- /dev/null
+++ b/app/tests/unit/forms/common/middleware/rateLimiter.spec.js
@@ -0,0 +1,144 @@
+const { getMockReq, getMockRes } = require('@jest-mock/express');
+const uuid = require('uuid');
+
+const { apiKeyRateLimiter } = require('../../../../../src/forms/common/middleware');
+
+const rateLimit = 7;
+const rateWindowSeconds = 11;
+
+jest.mock('config', () => {
+  return {
+    get: jest.fn((key) => {
+      if (key === 'server.rateLimit.public.max') {
+        return rateLimit;
+      }
+
+      if (key === 'server.rateLimit.public.windowMs') {
+        return rateWindowSeconds * 1000;
+      }
+    }),
+  };
+});
+
+// Headers for Draft 7 of the standard.
+const rateLimitName = 'RateLimit';
+const rateLimitValue = `limit=${rateLimit}, remaining=${rateLimit - 1}, reset=${rateWindowSeconds}`;
+const rateLimitPolicyName = 'RateLimit-Policy';
+const rateLimitPolicyValue = `${rateLimit};w=${rateWindowSeconds}`;
+
+const ipAddress = '1.2.3.4';
+
+const formId = uuid.v4();
+const secret = uuid.v4();
+const basicToken = Buffer.from(`${formId}:${secret}`).toString('base64');
+
+const bearerToken = Math.random().toString(36).substring(2);
+
+beforeEach(() => {
+  // Reset the rate limiting to be able to call the rate limiter multiple times
+  apiKeyRateLimiter.resetKey(ipAddress);
+});
+
+describe('apiKeyRateLimiter', () => {
+  it('rate limits basic auth', async () => {
+    const req = getMockReq({
+      headers: {
+        authorization: 'Basic ' + basicToken,
+      },
+      ip: ipAddress,
+    });
+    req.app.get = jest.fn().mockReturnValue();
+    const { res, next } = getMockRes();
+
+    await apiKeyRateLimiter(req, res, next);
+
+    expect(res.setHeader).toHaveBeenCalledTimes(2);
+    // These also test that the rate limiter uses our custom config values.
+    expect(res.setHeader).toHaveBeenNthCalledWith(1, rateLimitPolicyName, rateLimitPolicyValue);
+    expect(res.setHeader).toHaveBeenNthCalledWith(2, rateLimitName, rateLimitValue);
+    expect(next).toHaveBeenCalledTimes(1);
+    expect(next).toHaveBeenCalledWith();
+  });
+
+  describe('skips rate limiting for', () => {
+    test('no headers', async () => {
+      const req = getMockReq({
+        ip: ipAddress,
+      });
+      req.app.get = jest.fn().mockReturnValue();
+      const { res, next } = getMockRes();
+
+      await apiKeyRateLimiter(req, res, next);
+
+      expect(res.setHeader).toHaveBeenCalledTimes(0);
+      expect(next).toHaveBeenCalledTimes(1);
+      expect(next).toHaveBeenCalledWith();
+    });
+
+    test('no authorization header', async () => {
+      const req = getMockReq({
+        headers: {},
+        ip: ipAddress,
+      });
+      req.app.get = jest.fn().mockReturnValue();
+      const { res, next } = getMockRes();
+
+      await apiKeyRateLimiter(req, res, next);
+
+      expect(res.setHeader).toHaveBeenCalledTimes(0);
+      expect(next).toHaveBeenCalledTimes(1);
+      expect(next).toHaveBeenCalledWith();
+    });
+
+    test('empty authorization header', async () => {
+      const req = getMockReq({
+        headers: {
+          authorization: '',
+        },
+        ip: ipAddress,
+      });
+      req.app.get = jest.fn().mockReturnValue();
+      const { res, next } = getMockRes();
+
+      await apiKeyRateLimiter(req, res, next);
+
+      expect(res.setHeader).toHaveBeenCalledTimes(0);
+      expect(next).toHaveBeenCalledTimes(1);
+      expect(next).toHaveBeenCalledWith();
+    });
+
+    test('unexpected authorization type', async () => {
+      const req = getMockReq({
+        headers: {
+          authorization: Math.random().toString(36).substring(2),
+        },
+        ip: ipAddress,
+      });
+      req.app.get = jest.fn().mockReturnValue();
+      const { res, next } = getMockRes();
+
+      await apiKeyRateLimiter(req, res, next);
+
+      expect(res.setHeader).toHaveBeenCalledTimes(0);
+      expect(next).toHaveBeenCalledTimes(1);
+      expect(next).toHaveBeenCalledWith();
+    });
+
+    test('bearer auth', async () => {
+      const req = getMockReq({
+        headers: {
+          authorization: 'Bearer ' + bearerToken,
+        },
+        ip: ipAddress,
+      });
+      req.app.get = jest.fn().mockReturnValue();
+      const { res, next } = getMockRes();
+
+      await apiKeyRateLimiter(req, res, next);
+
+      expect(res.setHeader).toHaveBeenCalledTimes(0);
+      expect(next).toHaveBeenCalledTimes(1);
+      expect(next).toHaveBeenCalledWith();
+    });
+  });
+});