fix(adapter/aws-lambda): add alb event requestContext undefined check…

… for testing convenience (#3691)

* Add alb event null check for testing convenience

* Add tests for getProcessor function

* Export processor classes and add instanceOf assertions in tests

runtime-tests/lambda/index.test.ts

@@ -1,6 +1,17 @@
 import { Readable } from 'stream'
-import { handle, streamHandle } from '../../src/adapter/aws-lambda/handler'
-import type { LambdaEvent } from '../../src/adapter/aws-lambda/handler'
+import {
+  ALBProcessor,
+  EventV1Processor,
+  EventV2Processor,
+  getProcessor,
+  handle,
+  streamHandle,
+} from '../../src/adapter/aws-lambda/handler'
+import type {
+  ALBProxyEvent,
+  APIGatewayProxyEventV2,
+  LambdaEvent,
+} from '../../src/adapter/aws-lambda/handler'
 import type {
   ApiGatewayRequestContext,
   ApiGatewayRequestContextV2,
@@ -967,3 +978,53 @@ describe('streamHandle function', () => {
     expect(output).toContain(jsonResponsePrelude.replace(nullSequence, ''))
   })
 })
+
+describe('getProcessor function', () => {
+  it('Should return ALBProcessor for an ALBProxyEvent event', () => {
+    const event: ALBProxyEvent = {
+      httpMethod: 'GET',
+      path: '/',
+      body: null,
+      isBase64Encoded: false,
+      requestContext: {
+        elb: {
+          targetGroupArn:
+            'arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/lambda-279XGJDqGZ5rsrHC2Fjr/49e9d65c45c6791a',
+        },
+      },
+    }
+
+    const processor = getProcessor(event)
+    expect(processor).toBeInstanceOf(ALBProcessor)
+  })
+
+  it('Should return EventV1Processor for an event without requestContext', () => {
+    const event = {
+      httpMethod: 'GET',
+      path: '/',
+      body: null,
+      isBase64Encoded: false,
+    }
+
+    // while LambdaEvent RequestContext property is mandatory, it can be absent when testing through invoke-api or AWS Console
+    // in such cases, a V1 processor should be returned
+    const processor = getProcessor(event as unknown as LambdaEvent)
+    expect(processor).toBeInstanceOf(EventV1Processor)
+  })
+
+  it('Should return EventV2Processor for an APIGatewayProxyEventV2 event', () => {
+    const event: APIGatewayProxyEventV2 = {
+      version: '2.0',
+      routeKey: '$default',
+      headers: { 'content-type': 'text/plain' },
+      rawPath: '/',
+      rawQueryString: '',
+      body: null,
+      isBase64Encoded: false,
+      requestContext: testApiGatewayRequestContextV2,
+    }
+
+    const processor = getProcessor(event)
+    expect(processor).toBeInstanceOf(EventV2Processor)
+  })
+})

src/adapter/aws-lambda/handler.ts

@@ -184,7 +184,7 @@ export const handle = <E extends Env = Env, S extends Schema = {}, BasePath exte
   }
 }
 
-abstract class EventProcessor<E extends LambdaEvent> {
+export abstract class EventProcessor<E extends LambdaEvent> {
   protected abstract getPath(event: E): string
 
   protected abstract getMethod(event: E): string
@@ -272,7 +272,7 @@ abstract class EventProcessor<E extends LambdaEvent> {
   }
 }
 
-class EventV2Processor extends EventProcessor<APIGatewayProxyEventV2> {
+export class EventV2Processor extends EventProcessor<APIGatewayProxyEventV2> {
   protected getPath(event: APIGatewayProxyEventV2): string {
     return event.rawPath
   }
@@ -315,7 +315,7 @@ class EventV2Processor extends EventProcessor<APIGatewayProxyEventV2> {
 
 const v2Processor: EventV2Processor = new EventV2Processor()
 
-class EventV1Processor extends EventProcessor<Exclude<LambdaEvent, APIGatewayProxyEventV2>> {
+export class EventV1Processor extends EventProcessor<Exclude<LambdaEvent, APIGatewayProxyEventV2>> {
   protected getPath(event: Exclude<LambdaEvent, APIGatewayProxyEventV2>): string {
     return event.path
   }
@@ -375,7 +375,7 @@ class EventV1Processor extends EventProcessor<Exclude<LambdaEvent, APIGatewayPro
 
 const v1Processor: EventV1Processor = new EventV1Processor()
 
-class ALBProcessor extends EventProcessor<ALBProxyEvent> {
+export class ALBProcessor extends EventProcessor<ALBProxyEvent> {
   protected getHeaders(event: ALBProxyEvent): Headers {
     const headers = new Headers()
     // if multiValueHeaders is present the ALB will use it instead of the headers field
@@ -407,7 +407,7 @@ class ALBProcessor extends EventProcessor<ALBProxyEvent> {
 
   protected getQueryString(event: ALBProxyEvent): string {
     // In the case of ALB Integration either queryStringParameters or multiValueQueryStringParameters can be present not both
-    /* 
+    /*
       In other cases like when using the serverless framework, the event object does contain both queryStringParameters and multiValueQueryStringParameters:
       Below is an example event object for this URL: /payment/b8c55e69?select=amount&select=currency
       {
@@ -471,7 +471,10 @@ export const getProcessor = (event: LambdaEvent): EventProcessor<LambdaEvent> =>
 }
 
 const isProxyEventALB = (event: LambdaEvent): event is ALBProxyEvent => {
-  return Object.hasOwn(event.requestContext, 'elb')
+  if (event.requestContext) {
+    return Object.hasOwn(event.requestContext, 'elb')
+  }
+  return false
 }
 
 const isProxyEventV2 = (event: LambdaEvent): event is APIGatewayProxyEventV2 => {