Fix middleware rewrite for _next/data (vercel#41341)

x-ref: [slack thread](https://vercel.slack.com/archives/C01224Q5M99/p1665161421775079?thread_ts=1664536480.045539&cid=C01224Q5M99) ## Bug - [x] Related issues linked using `fixes #number` - [x] Integration tests added - [ ] Errors have a helpful link attached, see `contributing.md`
ThisIsMissEm · Oct 11, 2022 · 3188658 · 3188658
1 parent 2b99db0
commit 3188658
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Showing 5 changed files with 50 additions and 2 deletions.
diff --git a/packages/next/server/next-server.ts b/packages/next/server/next-server.ts
@@ -1062,9 +1062,17 @@ export default class NextNodeServer extends BaseServer {
         name: '_next/data catchall',
         check: true,
         fn: async (req, res, params, _parsedUrl) => {
+          const isNextDataNormalizing = getRequestMeta(
+            req,
+            '_nextDataNormalizing'
+          )
+
           // Make sure to 404 for /_next/data/ itself and
           // we also want to 404 if the buildId isn't correct
           if (!params.path || params.path[0] !== this.buildId) {
+            if (isNextDataNormalizing) {
+              return { finished: false }
+            }
             await this.render404(req, res, _parsedUrl)
             return {
               finished: true,

diff --git a/packages/next/server/request-meta.ts b/packages/next/server/request-meta.ts
@@ -23,6 +23,7 @@ export interface RequestMeta {
   _nextRewroteUrl?: string
   _nextMiddlewareCookie?: string[]
   _protocol?: string
+  _nextDataNormalizing?: boolean
 }
 
 export function getRequestMeta(

diff --git a/packages/next/server/router.ts b/packages/next/server/router.ts
@@ -7,7 +7,11 @@ import type {
 } from '../shared/lib/router/utils/route-matcher'
 import type { RouteHas } from '../lib/load-custom-routes'
 
-import { getNextInternalQuery, NextUrlWithParsedQuery } from './request-meta'
+import {
+  addRequestMeta,
+  getNextInternalQuery,
+  NextUrlWithParsedQuery,
+} from './request-meta'
 import { getPathMatch } from '../shared/lib/router/utils/path-match'
 import { removeTrailingSlash } from '../shared/lib/router/utils/remove-trailing-slash'
 import { normalizeLocalePath } from '../shared/lib/i18n/normalize-locale-path'
@@ -189,7 +193,11 @@ export default class Router {
       ...(middlewareCatchAllRoute
         ? this.fsRoutes
             .filter((route) => route.name === '_next/data catchall')
-            .map((route) => ({ ...route, check: false }))
+            .map((route) => ({
+              ...route,
+              name: '_next/data normalizing',
+              check: false,
+            }))
         : []),
       ...this.headers,
       ...this.redirects,
@@ -433,6 +441,11 @@ export default class Router {
         }
 
         if (params) {
+          const isNextDataNormalizing = route.name === '_next/data normalizing'
+
+          if (isNextDataNormalizing) {
+            addRequestMeta(req, '_nextDataNormalizing', true)
+          }
           parsedUrlUpdated.pathname = matchPathname
           const result = await route.fn(
             req,
@@ -441,6 +454,10 @@ export default class Router {
             parsedUrlUpdated,
             upgradeHead
           )
+
+          if (isNextDataNormalizing) {
+            addRequestMeta(req, '_nextDataNormalizing', false)
+          }
           if (result.finished) {
             return true
           }

diff --git a/test/e2e/middleware-rewrites/app/middleware.js b/test/e2e/middleware-rewrites/app/middleware.js
@@ -13,6 +13,11 @@ export async function middleware(request) {
     return NextResponse.next()
   }
 
+  if (url.pathname.startsWith('/_next/data/missing-id')) {
+    console.log(`missing-id rewrite: ${url.toString()}`)
+    return NextResponse.rewrite('https://example.vercel.sh')
+  }
+
   if (url.pathname.includes('/to/some/404/path')) {
     return NextResponse.next({
       'x-matched-path': '/404',

diff --git a/test/e2e/middleware-rewrites/test/index.test.ts b/test/e2e/middleware-rewrites/test/index.test.ts
@@ -23,6 +23,23 @@ describe('Middleware Rewrite', () => {
   })
 
   function tests() {
+    it('should allow rewriting invalid buildId correctly', async () => {
+      const res = await fetchViaHTTP(
+        next.url,
+        '/_next/data/missing-id/hello.json',
+        undefined,
+        {
+          headers: {
+            'x-nextjs-data': '1',
+          },
+        }
+      )
+      expect(res.status).toBe(200)
+      expect(await res.text()).toContain('Example Domain')
+      await check(() => next.cliOutput, /missing-id rewrite/)
+      expect(next.cliOutput).toContain('/_next/data/missing-id/hello.json')
+    })
+
     it('should not have un-necessary data request on rewrite', async () => {
       const browser = await webdriver(next.url, '/to-blog/first', {
         waitHydration: false,