improv(event-handler): changed path parameter in middleware and routehandler signature (#4532)

Author: sdangol

packages/event-handler/src/rest/Router.ts

@@ -224,18 +224,15 @@ class Router {
       // this response should be overwritten by the handler, if it isn't
       // it means something went wrong with the middleware chain
       res: new Response('', { status: 500 }),
+      params: {},
     };
 
     try {
       const path = new URL(req.url).pathname as Path;
 
       const route = this.routeRegistry.resolve(method, path);
 
-      const handlerMiddleware: Middleware = async ({
-        params,
-        reqCtx,
-        next,
-      }) => {
+      const handlerMiddleware: Middleware = async ({ reqCtx, next }) => {
         if (route === null) {
           const notFoundRes = await this.handleError(
             new NotFoundError(`Route ${path} for method ${method} not found`),
@@ -251,7 +248,7 @@ class Router {
               ? route.handler
               : route.handler.bind(options.scope);
 
-          const handlerResult = await handler(params, reqCtx);
+          const handlerResult = await handler(reqCtx);
           reqCtx.res = handlerResultToWebResponse(
             handlerResult,
             reqCtx.res.headers
@@ -267,8 +264,8 @@ class Router {
         handlerMiddleware,
       ]);
 
+      requestContext.params = route?.params ?? {};
       const middlewareResult = await middleware({
-        params: route?.params ?? {},
         reqCtx: requestContext,
         next: () => Promise.resolve(),
       });

packages/event-handler/src/rest/utils.ts

@@ -150,7 +150,7 @@ export const isAPIGatewayProxyResult = (
  * ```
  */
 export const composeMiddleware = (middleware: Middleware[]): Middleware => {
-  return async ({ params, reqCtx, next }): Promise<HandlerResponse | void> => {
+  return async ({ reqCtx, next }): Promise<HandlerResponse | void> => {
     let index = -1;
     let result: HandlerResponse | undefined;
 
@@ -177,7 +177,6 @@ export const composeMiddleware = (middleware: Middleware[]): Middleware => {
       };
 
       const middlewareResult = await middlewareFn({
-        params,
         reqCtx,
         next: nextFn,
       });

packages/event-handler/src/types/rest.ts

@@ -19,6 +19,7 @@ type RequestContext = {
   event: APIGatewayProxyEvent;
   context: Context;
   res: Response;
+  params: Record<string, string>;
 };
 
 type ErrorResolveOptions = RequestContext & ResolveOptions;
@@ -60,10 +61,9 @@ type DynamicRoute = Route & CompiledRoute;
 
 type HandlerResponse = Response | JSONObject;
 
-type RouteHandler<
-  TParams = Record<string, unknown>,
-  TReturn = HandlerResponse,
-> = (args: TParams, reqCtx: RequestContext) => Promise<TReturn>;
+type RouteHandler<TReturn = HandlerResponse> = (
+  reqCtx: RequestContext
+) => Promise<TReturn>;
 
 type HttpMethod = keyof typeof HttpVerbs;
 
@@ -87,7 +87,6 @@ type RestRouteOptions = {
 type NextFunction = () => Promise<HandlerResponse | void>;
 
 type Middleware = (args: {
-  params: Record<string, string>;
   reqCtx: RequestContext;
   next: NextFunction;
 }) => Promise<void | HandlerResponse>;

packages/event-handler/tests/unit/rest/Router/basic-routing.test.ts

@@ -89,7 +89,7 @@ describe('Class: Router - Basic Routing', () => {
     const app = new Router();
     const testEvent = createTestEvent('/test', 'GET');
 
-    app.get('/test', async (_params, reqCtx) => {
+    app.get('/test', async (reqCtx) => {
       return {
         hasRequest: reqCtx.req instanceof Request,
         hasEvent: reqCtx.event === testEvent,
@@ -126,8 +126,8 @@ describe('Class: Router - Basic Routing', () => {
     app.post('/', async () => {
       return { actualPath: '/todos' };
     });
-    app.get('/:todoId', async ({ todoId }) => {
-      return { actualPath: `/todos/${todoId}` };
+    app.get('/:todoId', async (reqCtx) => {
+      return { actualPath: `/todos/${reqCtx.params.todoId}` };
     });
 
     // Act

packages/event-handler/tests/unit/rest/Router/decorators.test.ts

@@ -398,7 +398,7 @@ describe('Class: Router - Decorators', () => {
 
       class Lambda {
         @app.get('/test')
-        public async getTest(_params: any, reqCtx: any) {
+        public async getTest(reqCtx: any) {
           return {
             hasRequest: reqCtx.req instanceof Request,
             hasEvent: reqCtx.event === testEvent,

packages/event-handler/tests/unit/rest/Router/middleware.test.ts

@@ -138,8 +138,8 @@ describe('Class: Router - Middleware', () => {
       let middlewareParams: Record<string, string> | undefined;
       let middlewareOptions: RequestContext | undefined;
 
-      app.use(async ({ params, reqCtx, next }) => {
-        middlewareParams = params;
+      app.use(async ({ reqCtx, next }) => {
+        middlewareParams = reqCtx.params;
         middlewareOptions = reqCtx;
         await next();
       });

packages/event-handler/tests/unit/rest/middleware/compress.test.ts

@@ -1,8 +1,8 @@
 import { gzipSync } from 'node:zlib';
 import context from '@aws-lambda-powertools/testing-utils/context';
-import { Router } from 'src/rest/Router.js';
 import { beforeEach, describe, expect, it } from 'vitest';
 import { compress } from '../../../../src/rest/middleware/index.js';
+import { Router } from '../../../../src/rest/Router.js';
 import { createSettingHeadersMiddleware, createTestEvent } from '../helpers.js';
 
 describe('Compress Middleware', () => {