fix: keep __nextDataReq query param working

Author: pieh

src/run/handlers/server.ts

@@ -83,6 +83,15 @@ export default async (request: Request) => {
       },
     })
 
+    if (new URL(request.url).searchParams.get('__nextDataReq')) {
+      const NEXT_REQUEST_META = Symbol.for('NextInternalRequestMeta')
+      // @ts-expect-error NEXT_REQUEST_META doesn't exist in IncomingMessage type
+      const meta = req[NEXT_REQUEST_META] ?? {}
+      meta.isNextDataReq = true
+      // @ts-expect-error NEXT_REQUEST_META doesn't exist in IncomingMessage type
+      req[NEXT_REQUEST_META] = meta
+    }
+
     disableFaultyTransferEncodingHandling(res as unknown as ComputeJsOutgoingMessage)
 
     const requestContext = getRequestContext() ?? createRequestContext()

tests/e2e/edge-middleware.test.ts

@@ -52,3 +52,23 @@ 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?__nextDataReq=1`,
+    {
+      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/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: () =>