apollo-server-lambda: Test against a mock ALB; upgrade to fix it (#5291)

We want ASL to work behind ALB, not just API Gateway, so let's test
against both.

Upgrading `@vendia/serverless-express` gives us better support for ALB
query strings.

Based on #5290 by @kamaz.

Co-authored-by: Kamaz <kamaz@xsimple.org>

package.json

@@ -90,7 +90,7 @@
     "@types/test-listen": "1.1.0",
     "@types/type-is": "1.6.3",
     "@types/uuid": "8.3.0",
-    "@vendia/serverless-express": "4.3.7",
+    "@vendia/serverless-express": "4.3.9",
     "apollo-link": "1.2.14",
     "apollo-link-http": "1.5.17",
     "apollo-link-persisted-queries": "0.2.2",

packages/apollo-server-lambda/package.json

@@ -27,7 +27,7 @@
   },
   "dependencies": {
     "@types/aws-lambda": "^8.10.76",
-    "@vendia/serverless-express": "^4.3.7",
+    "@vendia/serverless-express": "^4.3.9",
     "apollo-server-core": "file:../apollo-server-core",
     "apollo-server-express": "file:../apollo-server-express",
     "express": "^4.17.1"

packages/apollo-server-lambda/src/__tests__/ApolloServer.test.ts

@@ -1,7 +1,7 @@
 import http from 'http';
 import request from 'supertest';
 import express from 'express';
-import { createMockServer } from './mockServer';
+import { createMockServer } from './mockAPIGatewayServer';
 import { Config, gql } from 'apollo-server-core';
 import { ApolloServer, CreateHandlerOptions } from '../ApolloServer';
 import {

packages/apollo-server-lambda/src/__tests__/lambdaApollo.test.ts

@@ -4,18 +4,33 @@ import testSuite, {
   CreateAppOptions,
 } from 'apollo-server-integration-testsuite';
 import { Config } from 'apollo-server-core';
-import {createMockServer} from './mockServer';
+import { createMockServer as createAPIGatewayMockServer } from './mockAPIGatewayServer';
+import { createMockServer as createALBMockServer } from './mockALBServer';
 
-const createLambda = async (options: CreateAppOptions = {}) => {
+const createAPIGatewayLambda = async (options: CreateAppOptions = {}) => {
   const server = new ApolloServer(
     (options.graphqlOptions as Config) || { schema: Schema },
   );
 
   const handler = server.createHandler();
 
-  return createMockServer(handler);
-}
+  return createAPIGatewayMockServer(handler);
+};
 
-describe('integration:Lambda', () => {
-  testSuite({createApp: createLambda, serverlessFramework: true});
+const createALBLambda = async (options: CreateAppOptions = {}) => {
+  const server = new ApolloServer(
+    (options.graphqlOptions as Config) || { schema: Schema },
+  );
+
+  const handler = server.createHandler();
+
+  return createALBMockServer(handler);
+};
+
+describe('integration:APIGateway:Lambda', () => {
+  testSuite({ createApp: createAPIGatewayLambda, serverlessFramework: true });
+});
+
+describe('integration:ALB:Lambda', () => {
+  testSuite({ createApp: createALBLambda, serverlessFramework: true });
 });

packages/apollo-server-lambda/src/__tests__/mockALBServer.ts

@@ -0,0 +1,53 @@
+import url from 'url';
+import { IncomingMessage, ServerResponse } from 'http';
+import {
+  Context as LambdaContext,
+  ALBHandler,
+  ALBEvent,
+  ALBResult,
+} from 'aws-lambda';
+
+export function createMockServer(handler: ALBHandler) {
+  return (req: IncomingMessage, res: ServerResponse) => {
+    let body = '';
+    req.on('data', (chunk) => (body += chunk));
+    // this is an unawaited async function, but anything that causes it to
+    // reject should cause a test to fail
+    req.on('end', async () => {
+      const urlObject = url.parse(req.url || '', true);
+      const queryStringParameters = Object.entries(urlObject.query)
+        .map(([key, value]) => {
+          return [key, encodeURIComponent(value as string)];
+        })
+        .reduce((acc, [key, value]) => ({ [key]: value, ...acc }), {});
+      const event = {
+        httpMethod: req.method,
+        body: body,
+        path: urlObject.pathname,
+        queryStringParameters,
+        requestContext: {
+          elb: {},
+        },
+        headers: req.headers,
+      };
+      const result = (await handler(
+        event as unknown as ALBEvent,
+        {} as LambdaContext, // the fields aren't actually used now
+        () => {
+          throw Error("we don't use callback");
+        },
+      )) as ALBResult;
+      res.statusCode = result.statusCode!;
+      Object.entries(result.multiValueHeaders ?? {}).forEach(
+        ([key, values]) => {
+          res.setHeader(
+            key,
+            values.map((v) => v.toString()),
+          );
+        },
+      );
+      res.write(result.body);
+      res.end();
+    });
+  };
+}