fix: apply caching headers to pages router 404 with getStaticProps

src/build/content/prerendered.ts

@@ -57,6 +57,7 @@ const routeToFilePath = (path: string) => {
 
 const buildPagesCacheValue = async (
   path: string,
+  initialRevalidateSeconds: number | false | undefined,
   shouldUseEnumKind: boolean,
   shouldSkipJson = false,
 ): Promise<NetlifyCachedPageValue> => ({
@@ -65,6 +66,7 @@ const buildPagesCacheValue = async (
   pageData: shouldSkipJson ? {} : JSON.parse(await readFile(`${path}.json`, 'utf-8')),
   headers: undefined,
   status: undefined,
+  revalidate: initialRevalidateSeconds,
 })
 
 const buildAppCacheValue = async (
@@ -178,6 +180,7 @@ export const copyPrerenderedContent = async (ctx: PluginContext): Promise<void>
                   }
                   value = await buildPagesCacheValue(
                     join(ctx.publishDir, 'server/pages', key),
+                    meta.initialRevalidateSeconds,
                     shouldUseEnumKind,
                   )
                   break
@@ -210,6 +213,7 @@ export const copyPrerenderedContent = async (ctx: PluginContext): Promise<void>
           const key = routeToFilePath(route)
           const value = await buildPagesCacheValue(
             join(ctx.publishDir, 'server/pages', key),
+            undefined,
             shouldUseEnumKind,
             true, // there is no corresponding json file for fallback, so we are skipping it for this entry
           )

src/run/handlers/cache.cts

@@ -260,6 +260,11 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
 
           const { revalidate, ...restOfPageValue } = blob.value
 
+          const requestContext = getRequestContext()
+          if (requestContext) {
+            requestContext.pageHandlerRevalidate = revalidate
+          }
+
           await this.injectEntryToPrerenderManifest(key, revalidate)
 
           return {
@@ -272,6 +277,11 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
 
           const { revalidate, rscData, ...restOfPageValue } = blob.value
 
+          const requestContext = getRequestContext()
+          if (requestContext) {
+            requestContext.pageHandlerRevalidate = revalidate
+          }
+
           await this.injectEntryToPrerenderManifest(key, revalidate)
 
           return {

src/run/handlers/request-context.cts

@@ -21,6 +21,7 @@ export type RequestContext = {
   didPagesRouterOnDemandRevalidate?: boolean
   serverTiming?: string
   routeHandlerRevalidate?: NetlifyCachedRouteValue['revalidate']
+  pageHandlerRevalidate?: NetlifyCachedRouteValue['revalidate']
   /**
    * Track promise running in the background and need to be waited for.
    * Uses `context.waitUntil` if available, otherwise stores promises to

src/run/headers.ts

@@ -2,6 +2,7 @@ import type { Span } from '@opentelemetry/api'
 import type { NextConfigComplete } from 'next/dist/server/config-shared.js'
 
 import { encodeBlobKey } from '../shared/blobkey.js'
+import type { NetlifyCachedRouteValue } from '../shared/cache-types.cjs'
 
 import { getLogger, RequestContext } from './handlers/request-context.cjs'
 import type { RuntimeTracer } from './handlers/tracer.cjs'
@@ -208,6 +209,19 @@ export const adjustDateHeader = async ({
   headers.set('date', lastModifiedDate.toUTCString())
 }
 
+function setCacheControlFromRequestContext(
+  headers: Headers,
+  revalidate: NetlifyCachedRouteValue['revalidate'],
+) {
+  const cdnCacheControl =
+    // if we are serving already stale response, instruct edge to not attempt to cache that response
+    headers.get('x-nextjs-cache') === 'STALE'
+      ? 'public, max-age=0, must-revalidate, durable'
+      : `s-maxage=${revalidate === false ? 31536000 : revalidate}, stale-while-revalidate=31536000, durable`
+
+  headers.set('netlify-cdn-cache-control', cdnCacheControl)
+}
+
 /**
  * Ensure stale-while-revalidate and s-maxage don't leak to the client, but
  * assume the user knows what they are doing if CDN cache controls are set
@@ -225,13 +239,7 @@ export const setCacheControlHeaders = (
     !headers.has('netlify-cdn-cache-control')
   ) {
     // handle CDN Cache Control on Route Handler responses
-    const cdnCacheControl =
-      // if we are serving already stale response, instruct edge to not attempt to cache that response
-      headers.get('x-nextjs-cache') === 'STALE'
-        ? 'public, max-age=0, must-revalidate, durable'
-        : `s-maxage=${requestContext.routeHandlerRevalidate === false ? 31536000 : requestContext.routeHandlerRevalidate}, stale-while-revalidate=31536000, durable`
-
-    headers.set('netlify-cdn-cache-control', cdnCacheControl)
+    setCacheControlFromRequestContext(headers, requestContext.routeHandlerRevalidate)
     return
   }
 
@@ -242,11 +250,25 @@ export const setCacheControlHeaders = (
       .log('NetlifyHeadersHandler.trailingSlashRedirect')
   }
 
-  if (status === 404 && request.url.endsWith('.php')) {
-    // temporary CDN Cache Control handling for bot probes on PHP files
-    // https://linear.app/netlify/issue/FRB-1344/prevent-excessive-ssr-invocations-due-to-404-routes
-    headers.set('cache-control', 'public, max-age=0, must-revalidate')
-    headers.set('netlify-cdn-cache-control', `max-age=31536000, durable`)
+  if (status === 404) {
+    if (request.url.endsWith('.php')) {
+      // temporary CDN Cache Control handling for bot probes on PHP files
+      // https://linear.app/netlify/issue/FRB-1344/prevent-excessive-ssr-invocations-due-to-404-routes
+      headers.set('cache-control', 'public, max-age=0, must-revalidate')
+      headers.set('netlify-cdn-cache-control', `max-age=31536000, durable`)
+      return
+    }
+
+    if (
+      typeof requestContext.pageHandlerRevalidate !== 'undefined' &&
+      ['GET', 'HEAD'].includes(request.method) &&
+      !headers.has('cdn-cache-control') &&
+      !headers.has('netlify-cdn-cache-control')
+    ) {
+      // handle CDN Cache Control on 404 Page responses
+      setCacheControlFromRequestContext(headers, requestContext.pageHandlerRevalidate)
+      return
+    }
   }
 
   const cacheControl = headers.get('cache-control')

tests/integration/page-router.test.ts

@@ -126,6 +126,10 @@ test<FixtureTestContext>('Should serve correct locale-aware custom 404 pages', a
     load(responseImplicitDefaultLocale.body)('[data-testid="locale"]').text(),
     'Served 404 page content should use default locale if locale is not explicitly used in pathname (after basePath)',
   ).toBe('en')
+  expect(
+    responseImplicitDefaultLocale.headers['netlify-cdn-cache-control'],
+    'Response for not existing route if locale is not explicitly used in pathname (after basePath) should have 404 status',
+  ).toBe('s-maxage=31536000, stale-while-revalidate=31536000, durable')
 
   const responseExplicitDefaultLocale = await invokeFunction(ctx, {
     url: '/base/path/en/not-existing-page',
@@ -139,6 +143,10 @@ test<FixtureTestContext>('Should serve correct locale-aware custom 404 pages', a
     load(responseExplicitDefaultLocale.body)('[data-testid="locale"]').text(),
     'Served 404 page content should use default locale if default locale is explicitly used in pathname (after basePath)',
   ).toBe('en')
+  expect(
+    responseExplicitDefaultLocale.headers['netlify-cdn-cache-control'],
+    'Response for not existing route if locale is not explicitly used in pathname (after basePath) should have 404 status',
+  ).toBe('s-maxage=31536000, stale-while-revalidate=31536000, durable')
 
   const responseNonDefaultLocale = await invokeFunction(ctx, {
     url: '/base/path/fr/not-existing-page',
@@ -152,4 +160,8 @@ test<FixtureTestContext>('Should serve correct locale-aware custom 404 pages', a
     load(responseNonDefaultLocale.body)('[data-testid="locale"]').text(),
     'Served 404 page content should use non-default locale if non-default locale is explicitly used in pathname (after basePath)',
   ).toBe('fr')
+  expect(
+    responseNonDefaultLocale.headers['netlify-cdn-cache-control'],
+    'Response for not existing route if locale is not explicitly used in pathname (after basePath) should have 404 status',
+  ).toBe('s-maxage=31536000, stale-while-revalidate=31536000, durable')
 })