fix: don't run middleware on rewrite target (#270)

Author: ascorbic

edge-runtime/lib/response.ts

@@ -190,7 +190,7 @@ export const buildResponse = async ({
     }
     res.headers.set('x-middleware-rewrite', relativeUrl)
     request.headers.set('x-middleware-rewrite', target)
-    return addMiddlewareHeaders(fetch(new Request(target, request), { redirect: 'manual' }), res)
+    return addMiddlewareHeaders(context.rewrite(target), res)
   }
 
   // If we are redirecting a request that had a locale in the URL, we need to add it back in

package-lock.json

@@ -23,10 +23,21 @@ test('Does not run edge middleware at the origin', async ({ page, middleware })
   await expect(h1).toHaveText('Message from middleware: hello')
 })
 
+test('does not run middleware again for rewrite target', async ({ page, middleware }) => {
+  const direct = await page.goto(`${middleware.url}/test/rewrite-target`)
+  expect(await direct?.headerValue('x-added-rewrite-target')).toBeTruthy()
+
+  const rewritten = await page.goto(`${middleware.url}/test/rewrite-loop-detect`)
+
+  expect(await rewritten?.headerValue('x-added-rewrite-target')).toBeNull()
+  const h1 = page.locator('h1')
+  await expect(h1).toHaveText('Hello rewrite')
+})
+
 test('Supports CJS dependencies in Edge Middleware', async ({ page, middleware }) => {
   const res = await page.goto(`${middleware.url}/test/next`)
 
-  expect(await res?.headerValue('x-cjs-module-works')).toEqual("true")
+  expect(await res?.headerValue('x-cjs-module-works')).toEqual('true')
 })
 
 // adaptation of https://github.com/vercel/next.js/blob/8aa9a52c36f338320d55bd2ec292ffb0b8c7cb35/test/e2e/app-dir/metadata-edge/index.test.ts#L24C5-L31C7

tests/e2e/edge-middleware.test.ts

@@ -0,0 +1,7 @@
+export default function Rewrite() {
+  return (
+    <main>
+      <h1>Hello rewrite</h1>
+    </main>
+  )
+}

tests/fixtures/middleware/app/test/rewrite-target/page.js

@@ -45,6 +45,12 @@ const getResponse = (request: NextRequest) => {
     })
   }
 
+  if (request.nextUrl.pathname === '/test/rewrite-target') {
+    const response = NextResponse.next()
+    response.headers.set('x-added-rewrite-target', 'true')
+    return response
+  }
+
   if (request.nextUrl.pathname === '/test/rewrite-internal') {
     return NextResponse.rewrite(new URL('/rewrite-target', request.url), {
       request: {
@@ -53,6 +59,14 @@ const getResponse = (request: NextRequest) => {
     })
   }
 
+  if (request.nextUrl.pathname === '/test/rewrite-loop-detect') {
+    return NextResponse.rewrite(new URL('/test/rewrite-target', request.url), {
+      request: {
+        headers: requestHeaders,
+      },
+    })
+  }
+
   if (request.nextUrl.pathname === '/test/rewrite-external') {
     const requestURL = new URL(request.url)
     const externalURL = new URL(requestURL.searchParams.get('external-url') as string)

tests/fixtures/middleware/middleware.ts

@@ -0,0 +1 @@
+cool

tests/fixtures/simple-next-app-dist-dir/.gitignore

@@ -334,6 +334,32 @@ describe('page router', () => {
     expect(response.status).toBe(200)
   })
 
+  test<FixtureTestContext>('middleware should leave non-data requests untouched', async (ctx) => {
+    await createFixture('middleware-pages', ctx)
+    await runPlugin(ctx)
+    const origin = await LocalServer.run(async (req, res) => {
+      res.write(
+        JSON.stringify({
+          url: req.url,
+          headers: req.headers,
+        }),
+      )
+      res.end()
+    })
+    ctx.cleanup?.push(() => origin.stop())
+    const response = await invokeEdgeFunction(ctx, {
+      functions: ['___netlify-edge-handler-middleware'],
+      origin,
+      url: `/_next/static/build-id/_devMiddlewareManifest.json?foo=1`,
+    })
+    const res = await response.json()
+    const url = new URL(res.url, 'http://n/')
+    expect(url.pathname).toBe('/_next/static/build-id/_devMiddlewareManifest.json')
+    expect(url.search).toBe('?foo=1')
+    expect(res.headers['x-nextjs-data']).toBeUndefined()
+    expect(response.status).toBe(200)
+  })
+
   test<FixtureTestContext>('should rewrite un-rewritten data requests to page route', async (ctx) => {
     await createFixture('middleware-pages', ctx)
     await runPlugin(ctx)