Ensure node middleware is handled with standalone

packages/next/src/build/index.ts

@@ -595,6 +595,7 @@ async function writeStandaloneDirectory(
   outputFileTracingRoot: string,
   requiredServerFiles: RequiredServerFilesManifest,
   middlewareManifest: MiddlewareManifest,
+  hasNodeMiddleware: boolean,
   hasInstrumentationHook: boolean,
   staticPages: Set<string>,
   loadedEnvFiles: LoadedEnvFiles,
@@ -612,6 +613,7 @@ async function writeStandaloneDirectory(
         outputFileTracingRoot,
         requiredServerFiles.config,
         middlewareManifest,
+        hasNodeMiddleware,
         hasInstrumentationHook,
         staticPages
       )
@@ -638,6 +640,23 @@ async function writeStandaloneDirectory(
         })
         await fs.copyFile(filePath, outputPath)
       }
+
+      if (hasNodeMiddleware) {
+        const middlewareOutput = path.join(
+          distDir,
+          STANDALONE_DIRECTORY,
+          requiredServerFiles.config.distDir,
+          SERVER_DIRECTORY,
+          'middleware.js'
+        )
+
+        await fs.mkdir(path.dirname(middlewareOutput), { recursive: true })
+        await fs.copyFile(
+          path.join(distDir, SERVER_DIRECTORY, 'middleware.js'),
+          middlewareOutput
+        )
+      }
+
       await recursiveCopy(
         path.join(distDir, SERVER_DIRECTORY, 'pages'),
         path.join(
@@ -2324,6 +2343,7 @@ export default async function build(
       const middlewareFile = rootPaths.find((p) =>
         p.includes(MIDDLEWARE_FILENAME)
       )
+      let hasNodeMiddleware = false
 
       if (middlewareFile) {
         const staticInfo = await getStaticInfoIncludingLayouts({
@@ -2337,6 +2357,7 @@ export default async function build(
         })
 
         if (staticInfo.runtime === 'nodejs') {
+          hasNodeMiddleware = true
           functionsConfigManifest.functions['/_middleware'] = {
             runtime: staticInfo.runtime,
             matchers: staticInfo.middleware?.matchers ?? [
@@ -3543,6 +3564,7 @@ export default async function build(
           outputFileTracingRoot,
           requiredServerFilesManifest,
           middlewareManifest,
+          hasNodeMiddleware,
           hasInstrumentationHook,
           staticPages,
           loadedEnvFiles,

packages/next/src/build/utils.ts

@@ -1467,6 +1467,7 @@ export async function copyTracedFiles(
   tracingRoot: string,
   serverConfig: NextConfigComplete,
   middlewareManifest: MiddlewareManifest,
+  hasNodeMiddleware: boolean,
   hasInstrumentationHook: boolean,
   staticPages: Set<string>
 ) {
@@ -1581,6 +1582,12 @@ export async function copyTracedFiles(
     })
   }
 
+  if (hasNodeMiddleware) {
+    const middlewareFile = path.join(distDir, 'server', 'middleware.js')
+    const middlewareTrace = `${middlewareFile}.nft.json`
+    await handleTraceFiles(middlewareTrace)
+  }
+
   if (appPageKeys) {
     for (const page of appPageKeys) {
       if (middlewareManifest.functions.hasOwnProperty(page)) {

test/production/standalone-mode/required-server-files/middleware-node.js

@@ -0,0 +1,24 @@
+import { NextResponse } from 'next/server'
+import { ImageResponse } from 'next/og'
+import fs from 'fs'
+import path from 'path'
+
+export const config = {
+  runtime: 'nodejs',
+}
+
+export async function middleware(req) {
+  console.log('middleware', req.url)
+  console.log(
+    'env',
+    await fs.promises.readFile(path.join(process.cwd(), '.env'))
+  )
+
+  if (req.nextUrl.pathname === '/a-non-existent-page/to-test-with-middleware') {
+    return new ImageResponse(<div>Hello world</div>, {
+      width: 1200,
+      height: 600,
+    })
+  }
+  return NextResponse.next()
+}

test/production/standalone-mode/required-server-files/required-server-files-node-middleware.test.ts

@@ -0,0 +1,7 @@
+process.env.TEST_NODE_MIDDLEWARE = '1'
+
+if (process.env.TURBOPACK) {
+  it('should skip for now', () => {})
+} else {
+  require('./required-server-files.test')
+}

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

@@ -36,7 +36,14 @@ describe('required server files', () => {
       files: {
         pages: new FileRef(join(__dirname, 'pages')),
         lib: new FileRef(join(__dirname, 'lib')),
-        'middleware.js': new FileRef(join(__dirname, 'middleware.js')),
+        'middleware.js': new FileRef(
+          join(
+            __dirname,
+            process.env.TEST_NODE_MIDDLEWARE
+              ? 'middleware-node.js'
+              : 'middleware.js'
+          )
+        ),
         'cache-handler.js': new FileRef(join(__dirname, 'cache-handler.js')),
         'data.txt': new FileRef(join(__dirname, 'data.txt')),
         '.env': new FileRef(join(__dirname, '.env')),
@@ -49,6 +56,9 @@ describe('required server files', () => {
         eslint: {
           ignoreDuringBuilds: true,
         },
+        experimental: {
+          nodeMiddleware: Boolean(process.env.TEST_NODE_MIDDLEWARE),
+        },
         output: 'standalone',
         async rewrites() {
           return {
@@ -377,12 +387,17 @@ describe('required server files', () => {
   ;(process.env.TURBOPACK ? it.skip : it)(
     'should output middleware correctly',
     async () => {
-      // eslint-disable-next-line jest/no-standalone-expect
-      expect(
-        await fs.pathExists(
-          join(next.testDir, 'standalone/.next/server/edge-runtime-webpack.js')
-        )
-      ).toBe(true)
+      if (!process.env.TEST_NODE_MIDDLEWARE) {
+        // eslint-disable-next-line jest/no-standalone-expect
+        expect(
+          await fs.pathExists(
+            join(
+              next.testDir,
+              'standalone/.next/server/edge-runtime-webpack.js'
+            )
+          )
+        ).toBe(true)
+      }
       // eslint-disable-next-line jest/no-standalone-expect
       expect(
         await fs.pathExists(
@@ -1367,14 +1382,16 @@ describe('required server files', () => {
       expect(res.status).toBe(200)
       expect(await res.text()).toContain('index page')
 
-      if (process.env.TURBOPACK) {
-        expect(
-          fs.existsSync(join(standaloneDir, '.next/server/edge/chunks'))
-        ).toBe(true)
-      } else {
-        expect(
-          fs.existsSync(join(standaloneDir, '.next/server/edge-chunks'))
-        ).toBe(true)
+      if (!process.env.TEST_NODE_MIDDLEWARE) {
+        if (process.env.TURBOPACK) {
+          expect(
+            fs.existsSync(join(standaloneDir, '.next/server/edge/chunks'))
+          ).toBe(true)
+        } else {
+          expect(
+            fs.existsSync(join(standaloneDir, '.next/server/edge-chunks'))
+          ).toBe(true)
+        }
       }
 
       const resImageResponse = await fetchViaHTTP(