opennextjs · pieh · Jul 28, 2025
@@ -17,6 +17,7 @@ import { trace } from '@opentelemetry/api'
 import { wrapTracer } from '@opentelemetry/api/experimental'
 import glob from 'fast-glob'
 import type { MiddlewareManifest } from 'next/dist/build/webpack/plugins/middleware-plugin.js'
+import type { FunctionsConfigManifest } from 'next-with-cache-handler-v2/dist/build/index.js'
 import { prerelease, satisfies, lt as semverLowerThan, lte as semverLowerThanOrEqual } from 'semver'
 
 import type { RunConfig } from '../../run/config.js'
@@ -131,6 +132,10 @@ export const copyNextServerCode = async (ctx: PluginContext): Promise<void> => {
           return
         }
 
+        if (path === 'server/functions-config-manifest.json') {
+          await verifyFunctionsConfigManifest(join(srcDir, path))
+        }
+
         await cp(srcPath, destPath, { recursive: true, force: true })
       }),
     )
@@ -376,6 +381,19 @@ const replaceMiddlewareManifest = async (sourcePath: string, destPath: string) =
   await writeFile(destPath, newData)
 }
 
+const verifyFunctionsConfigManifest = async (sourcePath: string) => {
+  const data = await readFile(sourcePath, 'utf8')
+  const manifest = JSON.parse(data) as FunctionsConfigManifest
+
+  // https://github.com/vercel/next.js/blob/8367faedd61501025299e92d43a28393c7bb50e2/packages/next/src/build/index.ts#L2465
+  // Node.js Middleware has hardcoded /_middleware path
+  if (manifest.functions['/_middleware']) {
+    throw new Error(
+      'Only Edge Runtime Middleware is supported. Node.js Middleware is not supported.',
+    )
+  }
+}
+
 export const verifyHandlerDirStructure = async (ctx: PluginContext) => {
   const { nextConfig } = JSON.parse(
     await readFile(join(ctx.serverHandlerDir, RUN_CONFIG_FILE), 'utf-8'),

@@ -0,0 +1,12 @@
+export const metadata = {
+  title: 'Simple Next App',
+  description: 'Description for Simple Next App',
+}
+
+export default function RootLayout({ children }) {
+  return (
+    <html lang="en">
+      <body>{children}</body>
+    </html>
+  )
+}
@@ -0,0 +1,7 @@
+export default function Home() {
+  return (
+    <main>
+      <h1>Home</h1>
+    </main>
+  )
+}
@@ -0,0 +1,9 @@
+import type { NextRequest } from 'next/server'
+
+export async function middleware(request: NextRequest) {
+  console.log('Node.js Middleware request:', request.method, request.nextUrl.pathname)
+}
+
+export const config = {
+  runtime: 'nodejs',
+}
@@ -0,0 +1,12 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  output: 'standalone',
+  eslint: {
+    ignoreDuringBuilds: true,
+  },
+  experimental: {
+    nodeMiddleware: true,
+  },
+}
+
+module.exports = nextConfig
@@ -0,0 +1,20 @@
+{
+  "name": "middleware-node",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "postinstall": "next build",
+    "dev": "next dev",
+    "build": "next build"
+  },
+  "dependencies": {
+    "next": "latest",
+    "react": "18.2.0",
+    "react-dom": "18.2.0"
+  },
+  "test": {
+    "dependencies": {
+      "next": ">=15.2.0"
+    }
+  }
+}
@@ -4,6 +4,7 @@ import { type FixtureTestContext } from '../utils/contexts.js'
 import { createFixture, invokeEdgeFunction, runPlugin } from '../utils/fixture.js'
 import { generateRandomObjectID, startMockBlobStore } from '../utils/helpers.js'
 import { LocalServer } from '../utils/local-server.js'
+import { nextVersionSatisfies } from '../utils/next-version-helpers.mjs'
 
 beforeEach<FixtureTestContext>(async (ctx) => {
   // set for each test a new deployID and siteID
@@ -626,3 +627,13 @@ describe('page router', () => {
     expect(bodyFr.nextUrlLocale).toBe('fr')
   })
 })
+
+test.skipIf(!nextVersionSatisfies('>=15.2.0'))<FixtureTestContext>(
+  'should throw an Not Supported error when node middleware is used',
+  async (ctx) => {
+    await createFixture('middleware-node', ctx)
+    await expect(runPlugin(ctx)).rejects.toThrow(
+      'Only Edge Runtime Middleware is supported. Node.js Middleware is not supported.',
+    )
+  },
+)