isHttpHook: Support Koa ctx.req (#30)

Author: 72636c

.changeset/stale-zebras-pull.md

@@ -0,0 +1,5 @@
+---
+'@seek/aws-codedeploy-hooks': patch
+---
+
+isHttpHook: Support Koa `ctx.req`

packages/hooks/package.json

@@ -28,7 +28,11 @@
   "dependencies": {},
   "devDependencies": {
     "@aws-sdk/client-lambda": "3.485.0",
-    "@types/aws-lambda": "^8.10.130"
+    "@types/aws-lambda": "^8.10.130",
+    "@types/koa": "^2.13.6",
+    "@types/supertest": "^6.0.2",
+    "koa": "^2.15.0",
+    "supertest": "^6.3.4"
   },
   "engines": {
     "node": ">=18.12"

packages/hooks/src/http.test.ts

@@ -1,9 +1,28 @@
+import Koa from 'koa';
+import { agent } from 'supertest';
+
 import { isHttpHook } from './http';
 
 describe('isHttpHook', () => {
   it('is compatible with Request', () =>
     expect(isHttpHook(new Request('https://example.com'))).toBeDefined());
 
+  it('is compatible with Koa', () => {
+    const app = new Koa().use((ctx) => {
+      ctx.body = [
+        isHttpHook(ctx.req),
+        isHttpHook(ctx.request),
+        isHttpHook(ctx.request.req),
+      ];
+    });
+
+    // eslint-disable-next-line @typescript-eslint/no-misused-promises
+    return agent(app.callback())
+      .get('/')
+      .set('User-Agent', 'gantry-codedeploy-hook-BeforeAllowTraffic-dev/1.2.3')
+      .expect(200, [true, true, true]);
+  });
+
   it('recognises the Gantry hook', () =>
     expect(
       isHttpHook(
@@ -26,6 +45,19 @@ describe('isHttpHook', () => {
       ),
     ).toBe(true));
 
+  it('recognises one of multiple user agents', () =>
+    expect(
+      isHttpHook({
+        headers: {
+          'user-agent': [
+            'rogue-agent',
+            'aws-codedeploy-hook-BeforeAllowTraffic/123',
+            'secret-agent',
+          ],
+        },
+      }),
+    ).toBe(true));
+
   it('ignores a different user agent', () =>
     expect(
       isHttpHook(
@@ -37,6 +69,15 @@ describe('isHttpHook', () => {
       ),
     ).toBe(false));
 
+  it('ignores multiple different user agents', () =>
+    expect(
+      isHttpHook({
+        headers: {
+          'user-agent': ['Mozilla/5.0', 'Mozilla/6.0'],
+        },
+      }),
+    ).toBe(false));
+
   it.each(['Mozilla/5.0', null, undefined, true])(
     'ignores a missing user agent',
     () => expect(isHttpHook(new Request('https://example.com'))).toBe(false),

packages/hooks/src/http.ts

@@ -1,11 +1,17 @@
 import { GANTRY_HOOK_PREFIX, USER_AGENT_PREFIX } from './constants';
 
+type HeadersClass = { get: (name: string) => string | null };
+
+type HeadersRecord = Record<string, null | string | string[] | undefined>;
+
 type HttpRequest = {
-  headers: {
-    get: (name: string) => string | null;
-  };
+  headers: HeadersClass | HeadersRecord;
 };
 
+const isHeadersClass = (
+  headers: HttpRequest['headers'],
+): headers is HeadersClass => typeof headers.get === 'function';
+
 /**
  * Whether the HTTP request originated from AWS CodeDeploy Hooks.
  *
@@ -34,10 +40,15 @@ type HttpRequest = {
  * Compatible with Gantry v2.3.7 and newer.
  */
 export const isHttpHook = (req: HttpRequest): boolean => {
-  const userAgent = req.headers.get('user-agent');
+  const raw = isHeadersClass(req.headers)
+    ? req.headers.get('user-agent')
+    : req.headers['user-agent'];
+
+  const userAgents: string[] = raw ? [raw].flat() : [];
 
-  return Boolean(
-    userAgent?.startsWith(GANTRY_HOOK_PREFIX) ||
-      userAgent?.startsWith(USER_AGENT_PREFIX),
+  return userAgents.some(
+    (userAgent) =>
+      userAgent.startsWith(GANTRY_HOOK_PREFIX) ||
+      userAgent.startsWith(USER_AGENT_PREFIX),
   );
 };