opennextjs · sommeeeer · Feb 6, 2026 · Feb 6, 2026 · Feb 6, 2026 · Feb 6, 2026
diff --git a/.changeset/silver-taxis-kick.md b/.changeset/silver-taxis-kick.md
@@ -0,0 +1,7 @@
+---
+"@opennextjs/aws": patch
+---
+
+fix(pages-router): Add patch for trustHostHeader using res.revalidate
+
+In pages router on Next 15 and 16 if you tried to `res.revalidate` you would run into this error: `Error: Failed to revalidate /path: Invariant: missing internal router-server-methods this is an internal bug`. This PR introduces a patch that always sets `context.trustHostHeader` as true in the runtime code.
diff --git a/examples/pages-router/src/middleware.ts b/examples/pages-router/src/middleware.ts
@@ -15,5 +15,5 @@ export function middleware(request: NextRequest) {
 }
 
 export const config = {
-  matcher: ["/"],
+  matcher: ["/", "/revalidate/:path*"],
 };
diff --git a/examples/pages-router/src/pages/api/revalidate.ts b/examples/pages-router/src/pages/api/revalidate.ts
@@ -0,0 +1,26 @@
+import type { NextApiRequest, NextApiResponse } from "next";
+
+type Data =
+  | { revalidated: true; path: string }
+  | { revalidated: false; message: string };
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse<Data>,
+) {
+  if (req.method !== "POST" && req.method !== "GET") {
+    return res
+      .status(405)
+      .json({ revalidated: false, message: "Method not allowed" });
+  }
+
+  const key = req.query.key;
+  if (!key || typeof key !== "string") {
+    return res.status(400).json({ revalidated: false, message: "Missing key" });
+  }
+
+  const path = `/revalidate/${key}`;
+
+  await res.revalidate(path);
+  return res.status(200).json({ revalidated: true, path });
+}
diff --git a/examples/pages-router/src/pages/revalidate/[key].tsx b/examples/pages-router/src/pages/revalidate/[key].tsx
@@ -0,0 +1,78 @@
+import type { GetStaticPropsContext, GetStaticPropsResult } from "next";
+import Head from "next/head";
+
+type Params = { key: string };
+
+type FakeRecord = {
+  key: string;
+  title: string;
+  updatedAt: string;
+};
+
+type Props = {
+  record: FakeRecord;
+};
+
+const fakeDb: Omit<FakeRecord, "updatedAt">[] = [
+  {
+    key: "1",
+    title: "First record",
+  },
+  {
+    key: "2",
+    title: "Second record",
+  },
+  {
+    key: "3",
+    title: "Third record",
+  },
+];
+
+export default function TestKeyPage({ record }: Props) {
+  return (
+    <div style={{ padding: 24 }}>
+      <Head>
+        <title>SSG Test — {record.key}</title>
+      </Head>
+      <h1>SSG Test Page</h1>
+      <p>
+        <strong>Key:</strong> {record.key}
+      </p>
+      <p>
+        <strong>Title:</strong> {record.title}
+      </p>
+      <p>
+        <strong>Updated:</strong>{" "}
+        <span data-testid="updated-at">{record.updatedAt}</span>
+      </p>
+      <p>Revalidate set in getStaticProps.</p>
+    </div>
+  );
+}
+
+export async function getStaticProps({
+  params,
+}: GetStaticPropsContext<Params>): Promise<GetStaticPropsResult<Props>> {
+  const found = fakeDb.find((item) => item.key === params?.key);
+
+  if (!found) {
+    return { notFound: true };
+  }
+
+  return {
+    props: {
+      record: {
+        ...found,
+        updatedAt: new Date().toISOString(),
+      },
+    },
+  };
+}
+
+export async function getStaticPaths() {
+  const paths = fakeDb.map((item) => ({
+    params: { key: item.key },
+  }));
+
+  return { paths, fallback: "blocking" };
+}
diff --git a/packages/open-next/src/build/createServerBundle.ts b/packages/open-next/src/build/createServerBundle.ts
@@ -207,6 +207,7 @@ async function generateBundle(
     patches.patchBackgroundRevalidation,
     patches.patchUseCacheForISR,
     patches.patchNodeEnvironment,
+    patches.patchPagesApiRuntimeProd,
     ...additionalCodePatches,
   ]);
 

diff --git a/packages/open-next/src/build/patch/patches/index.ts b/packages/open-next/src/build/patch/patches/index.ts
@@ -9,3 +9,4 @@ export { patchFetchCacheSetMissingWaitUntil } from "./patchFetchCacheWaitUntil.j
 export { patchBackgroundRevalidation } from "./patchBackgroundRevalidation.js";
 export { patchNodeEnvironment } from "./patchNodeEnvironment.js";
 export { patchOriginalNextConfig } from "./patchOriginalNextConfig.js";
+export { patchPagesApiRuntimeProd } from "./patchPagesApiRuntimeProd.js";
diff --git a/packages/open-next/src/build/patch/patches/patchPagesApiRuntimeProd.ts b/packages/open-next/src/build/patch/patches/patchPagesApiRuntimeProd.ts
@@ -0,0 +1,91 @@
+import { getCrossPlatformPathRegex } from "utils/regex.js";
+import { createPatchCode } from "../astCodePatcher.js";
+import type { CodePatcher } from "../codePatcher.js";
+
+// `context.trustHostHeader` is undefined in our case
+// Trust the host header when invoking `res.revalidate("/path")` from pages router
+// https://github.com/vercel/next.js/blob/178a4c7/packages/next/src/server/api-utils/node/api-resolver.ts#L301
+export const trustHostHeaderRule = `
+rule:
+  kind: member_expression
+  pattern: $CONTEXT.trustHostHeader
+  inside:
+    kind: parenthesized_expression
+    inside:
+      kind: if_statement
+      all:
+        - has:
+            regex: await
+            kind: statement_block
+            has:
+              kind: lexical_declaration
+              regex: HEAD
+              has:
+                kind: variable_declarator
+                has:
+                  kind: await_expression
+                  has:
+                    kind: call_expression
+                    has:
+                      kind: identifier
+                      regex: ^fetch$
+fix:
+  'true'
+`;
+
+// Use correct protocol when doing HEAD fetch for revalidation
+export const headFetchProtocolRule = `
+rule:
+  kind: string_fragment
+  regex: ^https://
+  inside:
+    kind: template_string
+    inside:
+      kind: arguments
+      has:
+        kind: object
+        regex: HEAD
+      inside:
+        kind: call_expression
+        inside:
+          kind: await_expression
+          regex: fetch
+          inside: 
+            kind: variable_declarator
+            inside:
+              kind: lexical_declaration
+              regex: x-vercel-cache
+              inside:
+                kind: statement_block
+                inside: 
+                  kind: if_statement
+fix:
+  '\${r.headers["x-forwarded-proto"] || "https"}://'
+`;
+
+const pathFilter = getCrossPlatformPathRegex(
+  String.raw`/next/dist/compiled/next-server/pages-api(-turbo)?\.runtime\.prod\.js$`,
+  {
+    escape: false,
+  },
+);
+
+export const patchPagesApiRuntimeProd: CodePatcher = {
+  name: "patch-pages-api-runtime-prod",
+  patches: [
+    // Trust the host header when invoking `res.revalidate("") from pages router
-    // Trust the host header when invoking `res.revalidate("") from pages router
-    // Trust the host header when invoking `res.revalidate("") from pages router
+    {
+      pathFilter,
+      contentFilter: /trustHostHeader/,
+      patchCode: createPatchCode(trustHostHeaderRule),
+      versions: ">=15.0.0",
+    },
+    // Use correct protocol when doing HEAD fetch for revalidation
-    // Use correct protocol when doing HEAD fetch for revalidation
-    // Use correct protocol when doing HEAD fetch for revalidation
+    {
+      pathFilter,
+      contentFilter: /https/,
+      patchCode: createPatchCode(headFetchProtocolRule),
+      versions: ">=15.0.0",
+    },
+  ],
+};
diff --git a/packages/tests-e2e/tests/pagesRouter/revalidate.test.ts b/packages/tests-e2e/tests/pagesRouter/revalidate.test.ts
@@ -0,0 +1,32 @@
+import { expect, test } from "@playwright/test";
+
+test("res.revalidate should work", async ({ page }) => {
+  // Load the page initially and get the initial updatedAt value
+  await page.goto("/revalidate/1");
+  const initialUpdatedAt = await page.getByTestId("updated-at").textContent();
+  expect(initialUpdatedAt).toBe(initialUpdatedAt);
+
+  // Reload the page again to ensure its SSG
+  await page.reload();
+  const reloadedUpdatedAt = await page.getByTestId("updated-at").textContent();
+  expect(reloadedUpdatedAt).toBe(initialUpdatedAt);
+
+  // Trigger revalidation via the API route
+  const res = await page.request.post("/api/revalidate/?key=1");
+  const json = await res.json();
+
+  expect(json).toEqual({ revalidated: true, path: "/revalidate/1" });
+
+  if (!res.ok()) {
+    throw new Error(`Failed to trigger revalidation: ${await res.text()}`);
+  }
+
+  // Reload the page to get the updated content after revalidation
+  // It should be greater than `initialUpdatedAt`
+  await page.reload();
+
+  const updatedUpdatedAt = await page.getByTestId("updated-at").textContent();
+  expect(new Date(updatedUpdatedAt!).getTime()).toBeGreaterThan(
+    new Date(initialUpdatedAt!).getTime(),
+  );
+});