From 2ea0e520f11db671486103c09612bffb906ab14e Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Mon, 31 Mar 2025 14:54:10 -0400
Subject: [PATCH 01/12] test: fixture for dynamic cms results

---
 tests/fixtures/dynamic-cms/README.md          |  1 +
 .../dynamic-cms/netlify/functions/cms.ts      | 24 ++++++++++++
 tests/fixtures/dynamic-cms/next.config.ts     | 10 +++++
 tests/fixtures/dynamic-cms/package.json       | 24 ++++++++++++
 tests/fixtures/dynamic-cms/pages/404.js       |  3 ++
 .../dynamic-cms/pages/api/revalidate.js       |  9 +++++
 .../dynamic-cms/pages/content/[...slug].js    | 37 +++++++++++++++++++
 7 files changed, 108 insertions(+)
 create mode 100644 tests/fixtures/dynamic-cms/README.md
 create mode 100644 tests/fixtures/dynamic-cms/netlify/functions/cms.ts
 create mode 100644 tests/fixtures/dynamic-cms/next.config.ts
 create mode 100644 tests/fixtures/dynamic-cms/package.json
 create mode 100644 tests/fixtures/dynamic-cms/pages/404.js
 create mode 100644 tests/fixtures/dynamic-cms/pages/api/revalidate.js
 create mode 100644 tests/fixtures/dynamic-cms/pages/content/[...slug].js

diff --git a/tests/fixtures/dynamic-cms/README.md b/tests/fixtures/dynamic-cms/README.md
new file mode 100644
index 0000000000..e9f8e0c8ce
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/README.md
@@ -0,0 +1 @@
+This fixture is meant to emulate dynamic content responses of a CMS-backed next site
diff --git a/tests/fixtures/dynamic-cms/netlify/functions/cms.ts b/tests/fixtures/dynamic-cms/netlify/functions/cms.ts
new file mode 100644
index 0000000000..243421e0be
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/netlify/functions/cms.ts
@@ -0,0 +1,24 @@
+import { getDeployStore } from '@netlify/blobs'
+import { Context } from '@netlify/functions'
+
+// publish or unpublish "cms content" depending on the sent operation
+export default async function handler(_request: Request, context: Context) {
+  const store = getDeployStore({ name: 'cms-content', consistency: 'strong' })
+  const BLOB_KEY = 'key'
+
+  const operation = context.params['operation']
+
+  if (operation === 'publish') {
+    await store.setJSON(BLOB_KEY, { content: true })
+  }
+
+  if (operation === 'unpublish') {
+    await store.delete(BLOB_KEY)
+  }
+
+  return Response.json({ ok: true })
+}
+
+export const config = {
+  path: '/cms/:operation',
+}
diff --git a/tests/fixtures/dynamic-cms/next.config.ts b/tests/fixtures/dynamic-cms/next.config.ts
new file mode 100644
index 0000000000..6346ab0742
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/next.config.ts
@@ -0,0 +1,10 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  output: 'standalone',
+  eslint: {
+    ignoreDuringBuilds: true,
+  },
+  generateBuildId: () => 'build-id',
+}
+
+module.exports = nextConfig
diff --git a/tests/fixtures/dynamic-cms/package.json b/tests/fixtures/dynamic-cms/package.json
new file mode 100644
index 0000000000..33ebc7f177
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "dynamic-cms",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "postinstall": "next build",
+    "dev": "next dev",
+    "build": "next build"
+  },
+  "dependencies": {
+    "@netlify/blobs": "^8.1.0",
+    "@netlify/functions": "^2.7.0",
+    "@netlify/plugin-nextjs": "^5.10.1",
+    "netlify-cli": "^19.0.3",
+    "next": "latest",
+    "react": "18.2.0",
+    "react-dom": "18.2.0"
+  },
+  "devDependencies": {
+    "@types/node": "22.13.13",
+    "@types/react": "19.0.12",
+    "typescript": "5.8.2"
+  }
+}
diff --git a/tests/fixtures/dynamic-cms/pages/404.js b/tests/fixtures/dynamic-cms/pages/404.js
new file mode 100644
index 0000000000..3c251e6665
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/pages/404.js
@@ -0,0 +1,3 @@
+export default function NotFound() {
+  return <p>Custom 404 page</p>
+}
diff --git a/tests/fixtures/dynamic-cms/pages/api/revalidate.js b/tests/fixtures/dynamic-cms/pages/api/revalidate.js
new file mode 100644
index 0000000000..e134a56577
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/pages/api/revalidate.js
@@ -0,0 +1,9 @@
+export default async function handler(req, res) {
+  try {
+    const pathToPurge = req.query.path ?? '/static/revalidate-manual'
+    await res.revalidate(pathToPurge)
+    return res.json({ code: 200, message: 'success' })
+  } catch (err) {
+    return res.status(500).send({ code: 500, message: err.message })
+  }
+}
diff --git a/tests/fixtures/dynamic-cms/pages/content/[...slug].js b/tests/fixtures/dynamic-cms/pages/content/[...slug].js
new file mode 100644
index 0000000000..54abf74b16
--- /dev/null
+++ b/tests/fixtures/dynamic-cms/pages/content/[...slug].js
@@ -0,0 +1,37 @@
+import { getDeployStore } from '@netlify/blobs'
+
+const Content = ({ value }) => (
+  <div>
+    <p>
+      <span>{JSON.stringify(value)}</span>
+    </p>
+  </div>
+)
+
+export async function getStaticProps() {
+  const store = getDeployStore({ name: 'cms-content', consistency: 'strong' })
+  const BLOB_KEY = 'key'
+
+  const value = await store.get(BLOB_KEY, { type: 'json' })
+
+  if (!value) {
+    return {
+      notFound: true,
+    }
+  }
+
+  return {
+    props: {
+      value: value,
+    },
+  }
+}
+
+export const getStaticPaths = () => {
+  return {
+    paths: [],
+    fallback: 'blocking', // false or "blocking"
+  }
+}
+
+export default Content

From d278f66b9b9591dab474a0a335994d8b006257c2 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Mon, 31 Mar 2025 14:54:49 -0400
Subject: [PATCH 02/12] test: case for invalidating dynamic 404 pages

---
 tests/e2e/dynamic-cms.test.ts     | 52 +++++++++++++++++++++++++++++++
 tests/utils/create-e2e-fixture.ts |  1 +
 2 files changed, 53 insertions(+)
 create mode 100644 tests/e2e/dynamic-cms.test.ts

diff --git a/tests/e2e/dynamic-cms.test.ts b/tests/e2e/dynamic-cms.test.ts
new file mode 100644
index 0000000000..cb0ac01828
--- /dev/null
+++ b/tests/e2e/dynamic-cms.test.ts
@@ -0,0 +1,52 @@
+import { expect } from '@playwright/test'
+import { test } from '../utils/playwright-helpers.js'
+
+test.describe('Dynamic CMS', () => {
+  test('Invalidates 404 pages from durable cache', async ({ page, dynamicCms }) => {
+    // 1. Verify the status and headers of the dynamic page
+    const response1 = await page.goto(new URL('/content/blog', dynamicCms.url).href)
+    const headers1 = response1?.headers() || {}
+
+    expect(response1?.status()).toEqual(404)
+    expect(headers1['cache-control']).toEqual('public,max-age=0,must-revalidate')
+    expect(headers1['cache-status']).toEqual(
+      '"Next.js"; fwd=miss, "Netlify Durable"; fwd=uri-miss; stored, "Netlify Edge"; fwd=miss',
+    )
+    expect(headers1['netlify-cache-tag']).toEqual('_n_t_/content/blog')
+    expect(headers1['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+
+    // 2. Publish the blob, revalidate the dynamic page, and wait to regenerate
+    await page.goto(new URL('/cms/publish', dynamicCms.url).href)
+    await page.goto(new URL('/api/revalidate?path=/content/blog', dynamicCms.url).href)
+    await page.waitForTimeout(1000)
+
+    // 3. Verify the status and headers of the dynamic page
+    const response2 = await page.goto(new URL('/content/blog', dynamicCms.url).href)
+    const headers2 = response2?.headers() || {}
+
+    expect(response2?.status()).toEqual(200)
+    expect(headers2['cache-control']).toEqual('public,max-age=0,must-revalidate')
+    expect(headers2['cache-status']).toMatch(
+      /"Next.js"; hit, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
+    )
+    expect(headers2['netlify-cache-tag']).toEqual('_n_t_/content/blog')
+    expect(headers2['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+
+    // 4. Unpublish the blob, revalidate the dynamic page, and wait to regenerate
+    await page.goto(new URL('/cms/unpublish', dynamicCms.url).href)
+    await page.goto(new URL('/api/revalidate?path=/content/blog', dynamicCms.url).href)
+    await page.waitForTimeout(1000)
+
+    // 5. Verify the status and headers of the dynamic page
+    const response3 = await page.goto(new URL('/content/blog', dynamicCms.url).href)
+    const headers3 = response3?.headers() || {}
+
+    expect(response3?.status()).toEqual(404)
+    expect(headers3['cache-control']).toEqual('public,max-age=0,must-revalidate')
+    expect(headers3['cache-status']).toMatch(
+      /"Next.js"; fwd=miss, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
+    )
+    expect(headers3['netlify-cache-tag']).toEqual('_n_t_/content/blog')
+    expect(headers3['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+  })
+})
diff --git a/tests/utils/create-e2e-fixture.ts b/tests/utils/create-e2e-fixture.ts
index b133e6bc25..a2b5c48f00 100644
--- a/tests/utils/create-e2e-fixture.ts
+++ b/tests/utils/create-e2e-fixture.ts
@@ -440,5 +440,6 @@ export const fixtureFactories = {
       publishDirectory: 'apps/site/.next',
       smoke: true,
     }),
+  dynamicCms: () => createE2EFixture('dynamic-cms'),
   after: () => createE2EFixture('after'),
 }

From beec5f5b015f3fe41c477b4a37258fc8650f00ee Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Mon, 31 Mar 2025 14:54:59 -0400
Subject: [PATCH 03/12] fix: wip - fix for caching issues on catch all routes

---
 src/run/handlers/cache.cts |  5 +++--
 src/run/handlers/server.ts |  2 +-
 src/run/headers.ts         | 25 +++++++++++++++++++------
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/run/handlers/cache.cts b/src/run/handlers/cache.cts
index 294700901c..fbc546560b 100644
--- a/src/run/handlers/cache.cts
+++ b/src/run/handlers/cache.cts
@@ -121,11 +121,12 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
   }
 
   private captureCacheTags(cacheValue: NetlifyIncrementalCacheValue | null, key: string) {
+    const requestContext = getRequestContext()
+
     if (!cacheValue) {
       return
     }
 
-    const requestContext = getRequestContext()
     // Bail if we can't get request context
     if (!requestContext) {
       return
@@ -393,7 +394,7 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
 
       await this.cacheStore.set(key, { lastModified, value }, 'blobStore.set')
 
-      if (data?.kind === 'PAGE' || data?.kind === 'PAGES') {
+      if (!data || data?.kind === 'PAGE' || data?.kind === 'PAGES') {
         const requestContext = getRequestContext()
         if (requestContext?.didPagesRouterOnDemandRevalidate) {
           // encode here to deal with non ASCII characters in the key
diff --git a/src/run/handlers/server.ts b/src/run/handlers/server.ts
index 72666dd5b3..b0b23392d4 100644
--- a/src/run/handlers/server.ts
+++ b/src/run/handlers/server.ts
@@ -132,7 +132,7 @@ export default async (
     }
 
     setCacheControlHeaders(response, request, requestContext, nextConfig)
-    setCacheTagsHeaders(response.headers, requestContext)
+    setCacheTagsHeaders(response.headers, request, requestContext)
     setVaryHeaders(response.headers, request, nextConfig)
     setCacheStatusHeader(response.headers, nextCache)
 
diff --git a/src/run/headers.ts b/src/run/headers.ts
index bfc386506c..9f1d156437 100644
--- a/src/run/headers.ts
+++ b/src/run/headers.ts
@@ -220,7 +220,6 @@ export const setCacheControlHeaders = (
       .log('NetlifyHeadersHandler.trailingSlashRedirect')
   }
 
-  const cacheControl = headers.get('cache-control')
   if (status === 404) {
     if (request.url.endsWith('.php')) {
       // temporary CDN Cache Control handling for bot probes on PHP files
@@ -241,6 +240,8 @@ export const setCacheControlHeaders = (
     }
   }
 
+  const cacheControl = headers.get('cache-control')
+
   if (
     cacheControl !== null &&
     ['GET', 'HEAD'].includes(request.method) &&
@@ -273,6 +274,7 @@ export const setCacheControlHeaders = (
     ['GET', 'HEAD'].includes(request.method) &&
     !headers.has('cdn-cache-control') &&
     !headers.has('netlify-cdn-cache-control') &&
+    !new URL(request.url).pathname.startsWith('/api/') &&
     requestContext.usedFsReadForNonFallback
   ) {
     // handle CDN Cache Control on static files
@@ -281,13 +283,24 @@ export const setCacheControlHeaders = (
   }
 }
 
-export const setCacheTagsHeaders = (headers: Headers, requestContext: RequestContext) => {
-  if (
-    requestContext.responseCacheTags &&
-    (headers.has('cache-control') || headers.has('netlify-cdn-cache-control'))
-  ) {
+export const setCacheTagsHeaders = (
+  headers: Headers,
+  request: Request,
+  requestContext: RequestContext,
+) => {
+  if (!headers.has('cache-control') && !headers.has('netlify-cdn-cache-control')) {
+    return
+  }
+
+  if (requestContext.responseCacheTags) {
     headers.set('netlify-cache-tag', requestContext.responseCacheTags.join(','))
+    return
   }
+
+  const key = new URL(request.url).pathname
+  const cacheTag = `_N_T_${key === '/index' ? '/' : encodeURI(key)}`
+  console.log('setCacheTagsHeaders', 'netlify-cache-tag', key)
+  headers.set('netlify-cache-tag', cacheTag)
 }
 
 /**

From e95639ac609d6de931bb4b06b6f148884738e3fc Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 11:55:57 -0400
Subject: [PATCH 04/12] test: not all versions of next support next.config.ts

---
 tests/fixtures/dynamic-cms/{next.config.ts => next.config.js} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename tests/fixtures/dynamic-cms/{next.config.ts => next.config.js} (100%)

diff --git a/tests/fixtures/dynamic-cms/next.config.ts b/tests/fixtures/dynamic-cms/next.config.js
similarity index 100%
rename from tests/fixtures/dynamic-cms/next.config.ts
rename to tests/fixtures/dynamic-cms/next.config.js

From 1aee505b57f93c94104b0fe6e5de9d9c993d652d Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 11:57:29 -0400
Subject: [PATCH 05/12] test: older versions of next have different cache
 headers

---
 tests/e2e/dynamic-cms.test.ts | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tests/e2e/dynamic-cms.test.ts b/tests/e2e/dynamic-cms.test.ts
index cb0ac01828..d40f045257 100644
--- a/tests/e2e/dynamic-cms.test.ts
+++ b/tests/e2e/dynamic-cms.test.ts
@@ -13,7 +13,9 @@ test.describe('Dynamic CMS', () => {
       '"Next.js"; fwd=miss, "Netlify Durable"; fwd=uri-miss; stored, "Netlify Edge"; fwd=miss',
     )
     expect(headers1['netlify-cache-tag']).toEqual('_n_t_/content/blog')
-    expect(headers1['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+    expect(headers1['netlify-cdn-cache-control']).toMatch(
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+    )
 
     // 2. Publish the blob, revalidate the dynamic page, and wait to regenerate
     await page.goto(new URL('/cms/publish', dynamicCms.url).href)
@@ -30,7 +32,9 @@ test.describe('Dynamic CMS', () => {
       /"Next.js"; hit, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
     )
     expect(headers2['netlify-cache-tag']).toEqual('_n_t_/content/blog')
-    expect(headers2['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+    expect(headers2['netlify-cdn-cache-control']).toMatch(
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+    )
 
     // 4. Unpublish the blob, revalidate the dynamic page, and wait to regenerate
     await page.goto(new URL('/cms/unpublish', dynamicCms.url).href)
@@ -47,6 +51,8 @@ test.describe('Dynamic CMS', () => {
       /"Next.js"; fwd=miss, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
     )
     expect(headers3['netlify-cache-tag']).toEqual('_n_t_/content/blog')
-    expect(headers3['netlify-cdn-cache-control']).toEqual('s-maxage=31536000, durable')
+    expect(headers3['netlify-cdn-cache-control']).toMatch(
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+    )
   })
 })

From 2b0280bb4c18ce1bd79a7289e847a88d6ad30073 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 11:57:55 -0400
Subject: [PATCH 06/12] test: edge cache response depends on the node we hit

---
 tests/e2e/dynamic-cms.test.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/e2e/dynamic-cms.test.ts b/tests/e2e/dynamic-cms.test.ts
index d40f045257..92b9b2c020 100644
--- a/tests/e2e/dynamic-cms.test.ts
+++ b/tests/e2e/dynamic-cms.test.ts
@@ -29,7 +29,7 @@ test.describe('Dynamic CMS', () => {
     expect(response2?.status()).toEqual(200)
     expect(headers2['cache-control']).toEqual('public,max-age=0,must-revalidate')
     expect(headers2['cache-status']).toMatch(
-      /"Next.js"; hit, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
+      /"Next.js"; hit, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=(stale|miss)/,
     )
     expect(headers2['netlify-cache-tag']).toEqual('_n_t_/content/blog')
     expect(headers2['netlify-cdn-cache-control']).toMatch(
@@ -48,7 +48,7 @@ test.describe('Dynamic CMS', () => {
     expect(response3?.status()).toEqual(404)
     expect(headers3['cache-control']).toEqual('public,max-age=0,must-revalidate')
     expect(headers3['cache-status']).toMatch(
-      /"Next.js"; fwd=miss, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=stale/,
+      /"Next.js"; fwd=miss, "Netlify Durable"; fwd=stale; ttl=[0-9]+; stored, "Netlify Edge"; fwd=(stale|miss)/,
     )
     expect(headers3['netlify-cache-tag']).toEqual('_n_t_/content/blog')
     expect(headers3['netlify-cdn-cache-control']).toMatch(

From 0fd916d782f61688aa148de359b21e95533c4580 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:02:05 -0400
Subject: [PATCH 07/12] fix: set cache tags on 404 pages

---
 src/run/handlers/cache.cts | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/run/handlers/cache.cts b/src/run/handlers/cache.cts
index fbc546560b..e2ffbcbd22 100644
--- a/src/run/handlers/cache.cts
+++ b/src/run/handlers/cache.cts
@@ -123,10 +123,6 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
   private captureCacheTags(cacheValue: NetlifyIncrementalCacheValue | null, key: string) {
     const requestContext = getRequestContext()
 
-    if (!cacheValue) {
-      return
-    }
-
     // Bail if we can't get request context
     if (!requestContext) {
       return
@@ -142,6 +138,13 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
       return
     }
 
+    // Set cache tags for 404 pages as well so that the content can later be purged
+    if (!cacheValue) {
+      const cacheTags = [`_N_T_${key === '/index' ? '/' : encodeURI(key)}`]
+      requestContext.responseCacheTags = cacheTags
+      return
+    }
+
     if (
       cacheValue.kind === 'PAGE' ||
       cacheValue.kind === 'PAGES' ||

From d96b20c69519746fc10ddaaf8679120ba3775887 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:03:28 -0400
Subject: [PATCH 08/12] chore: clean up variable names

---
 src/run/handlers/cache.cts | 6 +++---
 src/run/revalidate.ts      | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/run/handlers/cache.cts b/src/run/handlers/cache.cts
index e2ffbcbd22..ffa35b795c 100644
--- a/src/run/handlers/cache.cts
+++ b/src/run/handlers/cache.cts
@@ -230,7 +230,7 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
     ...args: Parameters<CacheHandlerForMultipleVersions['get']>
   ): ReturnType<CacheHandlerForMultipleVersions['get']> {
     return this.tracer.withActiveSpan('get cache key', async (span) => {
-      const [key, ctx = {}] = args
+      const [key, context = {}] = args
       getLogger().debug(`[NetlifyCacheHandler.get]: ${key}`)
 
       span.setAttributes({ key })
@@ -263,7 +263,7 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
         return null
       }
 
-      const staleByTags = await this.checkCacheEntryStaleByTags(blob, ctx.tags, ctx.softTags)
+      const staleByTags = await this.checkCacheEntryStaleByTags(blob, context.tags, context.softTags)
 
       if (staleByTags) {
         span.addEvent('Stale', { staleByTags, key, ttl })
@@ -277,7 +277,7 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
         case 'FETCH':
           span.addEvent('FETCH', {
             lastModified: blob.lastModified,
-            revalidate: ctx.revalidate,
+            revalidate: context.revalidate,
             ttl,
           })
           return {
diff --git a/src/run/revalidate.ts b/src/run/revalidate.ts
index 25a5b86660..6789072209 100644
--- a/src/run/revalidate.ts
+++ b/src/run/revalidate.ts
@@ -15,8 +15,8 @@ function isRevalidateMethod(
 }
 
 // Needing to proxy the response object to intercept the revalidate call for on-demand revalidation on page routes
-export const nextResponseProxy = (res: ServerResponse, requestContext: RequestContext) => {
-  return new Proxy(res, {
+export const nextResponseProxy = (response: ServerResponse, requestContext: RequestContext) => {
+  return new Proxy(response, {
     get(target: ServerResponse, key: string) {
       const originalValue = Reflect.get(target, key)
       if (isRevalidateMethod(key, originalValue)) {

From de960f4c76e83e0cfcfb028516034f900747cdab Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:04:07 -0400
Subject: [PATCH 09/12] chore: remove previous attempt to set cache tags on
 404s

---
 src/run/handlers/server.ts | 2 +-
 src/run/headers.ts         | 7 -------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/src/run/handlers/server.ts b/src/run/handlers/server.ts
index b0b23392d4..72666dd5b3 100644
--- a/src/run/handlers/server.ts
+++ b/src/run/handlers/server.ts
@@ -132,7 +132,7 @@ export default async (
     }
 
     setCacheControlHeaders(response, request, requestContext, nextConfig)
-    setCacheTagsHeaders(response.headers, request, requestContext)
+    setCacheTagsHeaders(response.headers, requestContext)
     setVaryHeaders(response.headers, request, nextConfig)
     setCacheStatusHeader(response.headers, nextCache)
 
diff --git a/src/run/headers.ts b/src/run/headers.ts
index 9f1d156437..2495844bea 100644
--- a/src/run/headers.ts
+++ b/src/run/headers.ts
@@ -285,7 +285,6 @@ export const setCacheControlHeaders = (
 
 export const setCacheTagsHeaders = (
   headers: Headers,
-  request: Request,
   requestContext: RequestContext,
 ) => {
   if (!headers.has('cache-control') && !headers.has('netlify-cdn-cache-control')) {
@@ -294,13 +293,7 @@ export const setCacheTagsHeaders = (
 
   if (requestContext.responseCacheTags) {
     headers.set('netlify-cache-tag', requestContext.responseCacheTags.join(','))
-    return
   }
-
-  const key = new URL(request.url).pathname
-  const cacheTag = `_N_T_${key === '/index' ? '/' : encodeURI(key)}`
-  console.log('setCacheTagsHeaders', 'netlify-cache-tag', key)
-  headers.set('netlify-cache-tag', cacheTag)
 }
 
 /**

From 4cf7b2f400a31d1a067ca8e129fae04106cf3070 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:09:58 -0400
Subject: [PATCH 10/12] fix: also target 404 pages when purging cache

---
 src/run/handlers/cache.cts | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/run/handlers/cache.cts b/src/run/handlers/cache.cts
index ffa35b795c..6e51eb0129 100644
--- a/src/run/handlers/cache.cts
+++ b/src/run/handlers/cache.cts
@@ -271,7 +271,12 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
       }
 
       this.captureResponseCacheLastModified(blob, key, span)
-      this.captureCacheTags(blob.value, key)
+
+      // Next sets a kind/kindHint and fetchUrl for data requests, however fetchUrl was found to be most reliable across versions
+      const isDataRequest = Boolean(context.fetchUrl)
+      if (!isDataRequest) {
+        this.captureCacheTags(blob.value, key)
+      }
 
       switch (blob.value?.kind) {
         case 'FETCH':
@@ -391,13 +396,17 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
 
       const value = this.transformToStorableObject(data, context)
 
-      // if previous CacheHandler.get call returned null (page was either never rendered or was on-demand revalidated)
-      // and we didn't yet capture cache tags, we try to get cache tags from freshly produced cache value
-      this.captureCacheTags(value, key)
+      // Next sets a fetchCache and fetchUrl for data requests, however fetchUrl was found to be most reliable across versions
+      const isDataReq = Boolean(context.fetchUrl)
+      if (!isDataReq) {
+        // if previous CacheHandler.get call returned null (page was either never rendered or was on-demand revalidated)
+        // and we didn't yet capture cache tags, we try to get cache tags from freshly produced cache value
+        this.captureCacheTags(value, key)
+      }
 
       await this.cacheStore.set(key, { lastModified, value }, 'blobStore.set')
 
-      if (!data || data?.kind === 'PAGE' || data?.kind === 'PAGES') {
+      if ((!data && !isDataReq) || data?.kind === 'PAGE' || data?.kind === 'PAGES') {
         const requestContext = getRequestContext()
         if (requestContext?.didPagesRouterOnDemandRevalidate) {
           // encode here to deal with non ASCII characters in the key

From ca7ca4e0fc556b2bf5919a42e42abb4a5d16d104 Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:16:32 -0400
Subject: [PATCH 11/12] chore: remove wip check for cached api calls

---
 src/run/headers.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/run/headers.ts b/src/run/headers.ts
index 9776dd9058..471464c0c6 100644
--- a/src/run/headers.ts
+++ b/src/run/headers.ts
@@ -266,7 +266,6 @@ export const setCacheControlHeaders = (
     ['GET', 'HEAD'].includes(request.method) &&
     !headers.has('cdn-cache-control') &&
     !headers.has('netlify-cdn-cache-control') &&
-    !new URL(request.url).pathname.startsWith('/api/') &&
     requestContext.usedFsReadForNonFallback
   ) {
     // handle CDN Cache Control on static files

From cf47c741d27f84c64542ab0829a9b481c6b21a0a Mon Sep 17 00:00:00 2001
From: Mateusz Bocian <mrstork@users.noreply.github.com>
Date: Tue, 1 Apr 2025 12:20:01 -0400
Subject: [PATCH 12/12] chore: run format:fix

---
 src/run/handlers/cache.cts    | 6 +++++-
 src/run/headers.ts            | 5 +----
 tests/e2e/dynamic-cms.test.ts | 6 +++---
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/src/run/handlers/cache.cts b/src/run/handlers/cache.cts
index 6e51eb0129..4e9b61ce4a 100644
--- a/src/run/handlers/cache.cts
+++ b/src/run/handlers/cache.cts
@@ -263,7 +263,11 @@ export class NetlifyCacheHandler implements CacheHandlerForMultipleVersions {
         return null
       }
 
-      const staleByTags = await this.checkCacheEntryStaleByTags(blob, context.tags, context.softTags)
+      const staleByTags = await this.checkCacheEntryStaleByTags(
+        blob,
+        context.tags,
+        context.softTags,
+      )
 
       if (staleByTags) {
         span.addEvent('Stale', { staleByTags, key, ttl })
diff --git a/src/run/headers.ts b/src/run/headers.ts
index 471464c0c6..1931f61330 100644
--- a/src/run/headers.ts
+++ b/src/run/headers.ts
@@ -274,10 +274,7 @@ export const setCacheControlHeaders = (
   }
 }
 
-export const setCacheTagsHeaders = (
-  headers: Headers,
-  requestContext: RequestContext,
-) => {
+export const setCacheTagsHeaders = (headers: Headers, requestContext: RequestContext) => {
   if (!headers.has('cache-control') && !headers.has('netlify-cdn-cache-control')) {
     return
   }
diff --git a/tests/e2e/dynamic-cms.test.ts b/tests/e2e/dynamic-cms.test.ts
index 92b9b2c020..a157b47727 100644
--- a/tests/e2e/dynamic-cms.test.ts
+++ b/tests/e2e/dynamic-cms.test.ts
@@ -14,7 +14,7 @@ test.describe('Dynamic CMS', () => {
     )
     expect(headers1['netlify-cache-tag']).toEqual('_n_t_/content/blog')
     expect(headers1['netlify-cdn-cache-control']).toMatch(
-      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/,
     )
 
     // 2. Publish the blob, revalidate the dynamic page, and wait to regenerate
@@ -33,7 +33,7 @@ test.describe('Dynamic CMS', () => {
     )
     expect(headers2['netlify-cache-tag']).toEqual('_n_t_/content/blog')
     expect(headers2['netlify-cdn-cache-control']).toMatch(
-      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/,
     )
 
     // 4. Unpublish the blob, revalidate the dynamic page, and wait to regenerate
@@ -52,7 +52,7 @@ test.describe('Dynamic CMS', () => {
     )
     expect(headers3['netlify-cache-tag']).toEqual('_n_t_/content/blog')
     expect(headers3['netlify-cdn-cache-control']).toMatch(
-      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/
+      /s-maxage=31536000,( stale-while-revalidate=31536000,)? durable/,
     )
   })
 })