fix: Don't attach alternate links for redirects and consider port of a domain that is being redirected to (#1729)

Author: amannn

packages/next-intl/.size-limit.ts

@@ -42,7 +42,7 @@ const config: SizeLimitConfig = [
   {
     name: "import * from 'next-intl/middleware'",
     path: 'dist/esm/production/middleware.js',
-    limit: '9.305 KB'
+    limit: '9.315 KB'
   },
   {
     name: "import * from 'next-intl/routing'",

packages/next-intl/src/middleware/middleware.test.tsx

@@ -354,6 +354,14 @@ describe('prefix-based routing', () => {
       );
     });
 
+    it('does not return alternate links when redirecting', () => {
+      const response = middleware(
+        createMockRequest('/en', 'en', 'http://localhost:3000', 'de')
+      );
+      expect(MockedNextResponse.redirect).toHaveBeenCalled();
+      expect(response.headers.get('link')).toBe(null);
+    });
+
     it('sets a cookie when changing to the default locale', () => {
       const response = middleware(
         createMockRequest('/en', 'en', undefined, 'de')
@@ -3002,7 +3010,7 @@ describe('domain-based routing', () => {
         ]);
         expect(
           getLinks(
-            createMockRequest('/a-propos', 'fr', 'http://ca.example.com')
+            createMockRequest('/fr/a-propos', 'fr', 'http://ca.example.com')
           )
         ).toEqual([
           '<http://en.example.com/about>; rel="alternate"; hreflang="en"',
@@ -3045,7 +3053,7 @@ describe('domain-based routing', () => {
         expect(
           getLinks(
             createMockRequest(
-              '/fr/produits/apparel/t-shirts',
+              '/produits/apparel/t-shirts',
               'fr',
               'http://fr.example.com'
             )
@@ -3246,23 +3254,23 @@ describe('domain-based routing', () => {
             ?.split(', ');
         }
 
-        ['/en', '/uk'].forEach((pathname) => {
+        ['/', '/uk'].forEach((pathname) => {
           expect(getLinks(createMockRequest(pathname))).toEqual([
             '<http://localhost:3000/>; rel="alternate"; hreflang="en"',
             '<http://localhost:3000/uk>; rel="alternate"; hreflang="en-gb"',
             '<http://localhost:3000/>; rel="alternate"; hreflang="x-default"'
           ]);
         });
 
-        ['/en/about', '/uk/about'].forEach((pathname) => {
+        ['/about', '/uk/about'].forEach((pathname) => {
           expect(getLinks(createMockRequest(pathname))).toEqual([
             '<http://localhost:3000/about>; rel="alternate"; hreflang="en"',
             '<http://localhost:3000/uk/about>; rel="alternate"; hreflang="en-gb"',
             '<http://localhost:3000/about>; rel="alternate"; hreflang="x-default"'
           ]);
         });
 
-        expect(getLinks(createMockRequest('/en/unknown'))).toEqual([
+        expect(getLinks(createMockRequest('/unknown'))).toEqual([
           '<http://localhost:3000/unknown>; rel="alternate"; hreflang="en"',
           '<http://localhost:3000/uk/unknown>; rel="alternate"; hreflang="en-gb"',
           '<http://localhost:3000/unknown>; rel="alternate"; hreflang="x-default"'
@@ -3374,6 +3382,39 @@ describe('domain-based routing', () => {
       );
     });
 
+    it('keeps the port when there is a x-forwarded-host', () => {
+      createMiddleware({
+        defaultLocale: 'en',
+        locales: ['en', 'es'],
+        domains: [
+          {
+            domain: 'localhost:3000',
+            defaultLocale: 'en',
+            locales: ['en']
+          },
+          {
+            domain: 'localhost:3001',
+            defaultLocale: 'es',
+            locales: ['es']
+          }
+        ]
+      })(
+        createMockRequest(
+          '/en',
+          undefined,
+          'http://localhost:3001',
+          undefined,
+          {
+            'x-forwarded-host': 'localhost:3001'
+          }
+        )
+      );
+
+      expect(MockedNextResponse.redirect.mock.calls[0][0].toString()).toBe(
+        'http://localhost:3000/en'
+      );
+    });
+
     describe('base path', () => {
       it('redirects non-prefixed requests for the default locale', () => {
         middleware(

packages/next-intl/src/middleware/middleware.tsx

@@ -124,7 +124,11 @@ export default function createMiddleware<
             request.headers.get('x-forwarded-proto') ??
             request.nextUrl.protocol;
 
-          urlObj.port = request.headers.get('x-forwarded-port') ?? '';
+          const redirectDomainPort = redirectDomain.split(':')[1] as
+            | string
+            | undefined;
+          urlObj.port =
+            redirectDomainPort ?? request.headers.get('x-forwarded-port') ?? '';
         }
       }
 
@@ -135,6 +139,7 @@ export default function createMiddleware<
         );
       }
 
+      hasRedirected = true;
       return NextResponse.redirect(urlObj.toString());
     }
 
@@ -158,6 +163,7 @@ export default function createMiddleware<
 
     let response;
     let internalTemplateName: string | undefined;
+    let hasRedirected: boolean | undefined;
 
     let unprefixedInternalPathname = unprefixedExternalPathname;
     const pathnames = (resolvedRouting as any).pathnames as
@@ -304,6 +310,7 @@ export default function createMiddleware<
     syncCookie(request, response, locale, resolvedRouting, domain);
 
     if (
+      !hasRedirected &&
       resolvedRouting.localePrefix.mode !== 'never' &&
       resolvedRouting.alternateLinks &&
       resolvedRouting.locales.length > 1