fix: added cache control headers for static app routes

packages/next/src/server/base-server.ts

@@ -3292,7 +3292,10 @@ export default abstract class Server<
 
       // If cache control is already set on the response we don't
       // override it to allow users to customize it via next.config
-      if (cacheEntry.revalidate && !res.getHeader('Cache-Control')) {
+      if (
+        typeof cacheEntry.revalidate !== 'undefined' &&
+        !res.getHeader('Cache-Control')
+      ) {
         res.setHeader(
           'Cache-Control',
           formatRevalidate({
@@ -3315,7 +3318,10 @@ export default abstract class Server<
     } else if (cachedData.kind === CachedRouteKind.REDIRECT) {
       // If cache control is already set on the response we don't
       // override it to allow users to customize it via next.config
-      if (cacheEntry.revalidate && !res.getHeader('Cache-Control')) {
+      if (
+        typeof cacheEntry.revalidate !== 'undefined' &&
+        !res.getHeader('Cache-Control')
+      ) {
         res.setHeader(
           'Cache-Control',
           formatRevalidate({
@@ -3339,17 +3345,33 @@ export default abstract class Server<
         return null
       }
     } else if (cachedData.kind === CachedRouteKind.APP_ROUTE) {
-      const headers = { ...cachedData.headers }
+      const headers = fromNodeOutgoingHttpHeaders(cachedData.headers)
 
       if (!(this.minimalMode && isSSG)) {
-        delete headers[NEXT_CACHE_TAGS_HEADER]
+        headers.delete(NEXT_CACHE_TAGS_HEADER)
+      }
+
+      // If cache control is already set on the response we don't
+      // override it to allow users to customize it via next.config
+      if (
+        typeof cacheEntry.revalidate !== 'undefined' &&
+        !res.getHeader('Cache-Control') &&
+        !headers.get('Cache-Control')
+      ) {
+        headers.set(
+          'Cache-Control',
+          formatRevalidate({
+            revalidate: cacheEntry.revalidate,
+            expireTime: this.nextConfig.expireTime,
+          })
+        )
       }
 
       await sendResponse(
         req,
         res,
         new Response(cachedData.body, {
-          headers: fromNodeOutgoingHttpHeaders(headers),
+          headers,
           status: cachedData.status || 200,
         })
       )

test/production/standalone-mode/required-server-files/app/api/test/[slug]/route.js

@@ -0,0 +1,7 @@
+export const dynamic = 'force-static'
+
+export async function GET(request, context) {
+  const { params } = context
+  const { slug } = params
+  return Response.json({ message: `Hello, ${slug}!` })
+}

test/production/standalone-mode/required-server-files/app/test/[slug]/page.jsx

@@ -0,0 +1,9 @@
+export const revalidate = 3600
+
+export default function Page() {
+  return <div>Hello, World!</div>
+}
+
+export async function generateStaticParams() {
+  return []
+}

test/production/standalone-mode/required-server-files/required-server-files-app.test.ts

@@ -101,6 +101,32 @@ describe('required server files app router', () => {
     if (server) await killApp(server)
   })
 
+  it('should send the right cache headers for an app route', async () => {
+    const res = await fetchViaHTTP(appPort, '/api/test/123', undefined, {
+      headers: {
+        'x-matched-path': '/api/test/[slug]',
+        'x-now-route-matches': '1=123&nxtPslug=123',
+      },
+    })
+    expect(res.status).toBe(200)
+    expect(res.headers.get('cache-control')).toBe(
+      's-maxage=31536000, stale-while-revalidate'
+    )
+  })
+
+  it('should send the right cache headers for an app page', async () => {
+    const res = await fetchViaHTTP(appPort, '/test/123', undefined, {
+      headers: {
+        'x-matched-path': '/test/[slug]',
+        'x-now-route-matches': '1=123&nxtPslug=123',
+      },
+    })
+    expect(res.status).toBe(200)
+    expect(res.headers.get('cache-control')).toBe(
+      's-maxage=3600, stale-while-revalidate'
+    )
+  })
+
   it('should not fail caching', async () => {
     expect(next.cliOutput).not.toContain('ERR_INVALID_URL')
   })

test/turbopack-build-tests-manifest.json

@@ -16578,6 +16578,8 @@
     "test/production/standalone-mode/required-server-files/required-server-files-app.test.ts": {
       "passed": [],
       "failed": [
+        "required server files app router should send the right cache headers for an app route",
+        "required server files app router should send the right cache headers for an app page",
         "required server files app router should not fail caching",
         "required server files app router should not send cache tags in minimal mode for SSR",
         "required server files app router should not send invalid soft tags to cache handler",