fix: adjust middleware json data rewrite to work with recent next@canary

edge-runtime/lib/response.ts

@@ -14,6 +14,8 @@ import {
   normalizeLocalePath,
   normalizeTrailingSlash,
   relativizeURL,
+  removeBasePath,
+  rewriteDataPath,
 } from './util.ts'
 
 export interface FetchEventResult {
@@ -180,14 +182,16 @@ export const buildResponse = async ({
     }
 
     if (isDataReq) {
-      // The rewrite target is a data request, but a middleware rewrite target is always for the page route,
-      // so we need to tell the server this is a data request. Setting the `x-nextjs-data` header is not enough. 🤷
-      rewriteUrl.searchParams.set('__nextDataReq', '1')
+      rewriteUrl.pathname = rewriteDataPath({
+        dataUrl: new URL(request.url).pathname,
+        newRoute: removeBasePath(rewriteUrl.pathname, nextConfig?.basePath),
+        basePath: nextConfig?.basePath,
+      })
+    } else {
+      // respect trailing slash rules to prevent 308s
+      rewriteUrl.pathname = normalizeTrailingSlash(rewriteUrl.pathname, nextConfig?.trailingSlash)
     }
 
-    // respect trailing slash rules to prevent 308s
-    rewriteUrl.pathname = normalizeTrailingSlash(rewriteUrl.pathname, nextConfig?.trailingSlash)
-
     const target = normalizeLocalizedTarget({ target: rewriteUrl.toString(), request, nextConfig })
     if (target === request.url) {
       logger.withFields({ rewrite_url: rewrite }).debug('Rewrite url is same as original url')

tests/e2e/edge-middleware.test.ts

@@ -52,3 +52,20 @@ test('it should render OpenGraph image meta tag correctly', async ({ page, middl
   const size = await getImageSize(Buffer.from(imageBuffer), 'png')
   expect([size.width, size.height]).toEqual([1200, 630])
 })
+
+test('json data rewrite works', async ({ middlewarePages }) => {
+  const response = await fetch(`${middlewarePages.url}/_next/data/build-id/sha.json`, {
+    headers: {
+      'x-nextjs-data': '1',
+    },
+  })
+
+  expect(response.ok).toBe(true)
+  const body = await response.text()
+
+  expect(body).toMatch(/^{"pageProps":/)
+
+  const data = JSON.parse(body)
+
+  expect(data.pageProps.message).toBeDefined()
+})

tests/fixtures/middleware-pages/next-env.d.ts

@@ -2,4 +2,4 @@
 /// <reference types="next/image-types/global" />
 
 // NOTE: This file should not be edited
-// see https://nextjs.org/docs/basic-features/typescript for more information.
+// see https://nextjs.org/docs/pages/api-reference/config/typescript for more information.

tests/fixtures/middleware-pages/next.config.js

@@ -21,6 +21,7 @@ if (platform === 'win32') {
   }
 }
 
+/** @type {import('next').NextConfig} */
 module.exports = {
   trailingSlash: true,
   output: 'standalone',

tests/fixtures/middleware-pages/package.json

@@ -13,6 +13,8 @@
     "react-dom": "18.2.0"
   },
   "devDependencies": {
-    "@types/react": "18.2.47"
+    "@types/node": "^20.10.6",
+    "@types/react": "18.2.47",
+    "typescript": "^5.3.3"
   }
 }

tests/fixtures/middleware-pages/tsconfig.json

@@ -11,7 +11,8 @@
     "moduleResolution": "node",
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "jsx": "preserve"
+    "jsx": "preserve",
+    "target": "ES2017"
   },
   "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
   "exclude": ["node_modules"]

tests/integration/edge-handler.test.ts

@@ -387,8 +387,7 @@ describe('page router', () => {
     })
     const res = await response.json()
     const url = new URL(res.url, 'http://n/')
-    expect(url.pathname).toBe('/ssr-page-2/')
-    expect(url.searchParams.get('__nextDataReq')).toBe('1')
+    expect(url.pathname).toBe('/_next/data/build-id/ssr-page-2.json')
     expect(res.headers['x-nextjs-data']).toBe('1')
     expect(response.headers.get('x-nextjs-rewrite')).toBe('/ssr-page-2/')
     expect(response.status).toBe(200)
@@ -420,7 +419,7 @@ describe('page router', () => {
     expect(response.status).toBe(200)
   })
 
-  test<FixtureTestContext>('should rewrite un-rewritten data requests to page route', async (ctx) => {
+  test<FixtureTestContext>('should NOT rewrite un-rewritten data requests to page route', async (ctx) => {
     await createFixture('middleware-pages', ctx)
     await runPlugin(ctx)
     const origin = await LocalServer.run(async (req, res) => {
@@ -443,8 +442,7 @@ describe('page router', () => {
     })
     const res = await response.json()
     const url = new URL(res.url, 'http://n/')
-    expect(url.pathname).toBe('/ssg/hello/')
-    expect(url.searchParams.get('__nextDataReq')).toBe('1')
+    expect(url.pathname).toBe('/_next/data/build-id/ssg/hello.json')
     expect(res.headers['x-nextjs-data']).toBe('1')
     expect(response.status).toBe(200)
   })
@@ -472,8 +470,7 @@ describe('page router', () => {
     })
     const res = await response.json()
     const url = new URL(res.url, 'http://n/')
-    expect(url.pathname).toBe('/blog/first/')
-    expect(url.searchParams.get('__nextDataReq')).toBe('1')
+    expect(url.pathname).toBe('/_next/data/build-id/blog/first.json')
     expect(url.searchParams.get('slug')).toBe('first')
     expect(res.headers['x-nextjs-data']).toBe('1')
     expect(response.status).toBe(200)

tests/integration/page-router.test.ts

@@ -95,22 +95,6 @@ test<FixtureTestContext>('Should revalidate path with On-demand Revalidation', a
   expect(dateCacheInitial).not.toBe(dateCacheRevalidated)
 })
 
-test<FixtureTestContext>('Should return JSON for data req to page route', async (ctx) => {
-  await createFixture('page-router', ctx)
-  await runPlugin(ctx)
-
-  const response = await invokeFunction(ctx, {
-    url: '/static/revalidate-manual?__nextDataReq=1',
-    headers: { 'x-nextjs-data': '1' },
-  })
-
-  expect(response.body).toMatch(/^{"pageProps":/)
-
-  const data = JSON.parse(response.body)
-
-  expect(data.pageProps.show).toBeDefined()
-})
-
 test.skipIf(platform === 'win32')<FixtureTestContext>(
   'Should set permanent "netlify-cdn-cache-control" header on fully static pages"',
   async (ctx) => {

tests/utils/create-e2e-fixture.ts

@@ -325,6 +325,7 @@ export const fixtureFactories = {
   bun: () => createE2EFixture('simple', { packageManger: 'bun' }),
   middleware: () => createE2EFixture('middleware'),
   middlewareOg: () => createE2EFixture('middleware-og'),
+  middlewarePages: () => createE2EFixture('middleware-pages'),
   pageRouter: () => createE2EFixture('page-router'),
   pageRouterBasePathI18n: () => createE2EFixture('page-router-base-path-i18n'),
   turborepo: () =>