Port added to Domain

[FNGR2911]

Description

I use the middleware with domain-based routing and have the problem that the port is appended to the domain on my server when the domain is entered without a prefix.

For example:
frontend.domain.com => frontend.domain.com:3000/en
frontend.domain.ca => frontend.domain.ca:3000/fr

I use Caddy as a reverse proxy. If I enter the entire address including the language prefix (e.g. frontend.domain.com/en) it works without any problems and the port is not appended.

Mandatory reproduction URL (CodeSandbox or GitHub repository)

NA

Reproduction description

Next.js 14.0.3, next-intl 3.0

Domain Config:

const domains = [
  {
    id: 1,
    domain: 'frontend.domain.de',
    marketCode: 'de',
    defaultLocale: 'de',
    countryName: 'Germany',
    locales: ['de'],
    showInSelector: false
  },
  {
    id: 2,
    domain: 'frontend.domain.com',
    marketCode: 'en',
    defaultLocale: 'en',
    countryName: 'US',
    locales: ['en'],
    showInSelector: true
  },
  {
    id: 3,
    domain: 'frontend.domain.ca',
    marketCode: 'ca',
    defaultLocale: 'ca',
    countryName: 'Canada',
    locales: ['en', 'fr'],
    showInSelector: true
  }
]

Middleware:

import createIntlMiddleware from 'next-intl/middleware'
import { locales } from '@/translations/locales'
import { domains } from '@/translations/domains'

export default async function middleware(request) {
  const handleI18nRouting = createIntlMiddleware({
    locales: locales,
    defaultLocale: 'de',
    domains: domains,
    localePrefix: 'always'
  })
  const response = handleI18nRouting(request)

  return response
}

export const config = {
  matcher: ['/', '/(de|en|ru|nl|fr|pl)/:path*']
} 

Caddyfile:

{
    email mail@domain.com
}
frontend.domain.de {
    encode zstd gzip
    reverse_proxy frontend:3000

    header {
        Strict-Transport-Security max-age=31536000;
        X-Content-Type-Options nosniff
        X-Frame-Options DENY
        Referrer-Policy no-referrer-when-downgrade
    }
}
frontend.domain.com {
    encode zstd gzip
    reverse_proxy frontend:3000

    header {
        Strict-Transport-Security max-age=31536000;
        X-Content-Type-Options nosniff
        X-Frame-Options DENY
        Referrer-Policy no-referrer-when-downgrade
    }
}
frontend.domain.ca {
    encode zstd gzip
    reverse_proxy frontend:3000

    header {
        Strict-Transport-Security max-age=31536000;
        X-Content-Type-Options nosniff
        X-Frame-Options DENY
        Referrer-Policy no-referrer-when-downgrade
    }
}

Expected behaviour

The port will not be appended to the domain if I enter the domain without language prefix.

[amannn]

I unfortunately don't have any experience with Caddy. To look into this, it would be required that a reproduction is available that demonstrates incorrect behavior on the next-intl side.

We have quite an extensive test suite for the middleware. If you have a special use case, you can try to add a test there to see if the bug is caused by next-intl.

[github-actions]

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Thank you for your understanding!

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[7thkey]

This is happening to us using Docker Compose and using domains like es.midomain.com > mx.mydomain.com
To fix it temporarly we had to change the headers location in middleware

[DanWebb]

I'm also getting this issue, v3.1.3, not using anything fancy like Docker Compose or Caddy.

The port is being appended at some point in the domain-based redirect

[FNGR2911]

This is happening to us using Docker Compose and using domains like es.midomain.com > mx.mydomain.com To fix it temporarly we had to change the headers location in middleware

Do you have any example code how you did that @7thkey? Would be great, thank you!

[amannn]

I think I found the issue. If tests pass in #662, this will be fixed in the next patch version.

[DanWebb]

Nice!

In case it's still helpful, I was setting up a reproduction:

• EN URL
• CY URL

It's a bit awkward to reproduce as it needs two domains, but you can see the port there in the console-logged middleware response when going cy -> en.

[FNGR2911]

I think I found the issue. If tests pass in #662, this will be fixed in the next patch version.

Thank you @amannn! Sounds great.

[Quackzoer]

Was it fixed? I keep getting port added after upgrading next-intl package

[amannn]

@Quackzoer Can you open a new issue with a reproduction and more details about your setup?

[awkaiser-tr]

@amannn unfortunately the fix ...

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

Lines 97 to 104 in 553b8f4

	if (redirectDomain) {
	urlObj.protocol =
	request.headers.get('x-forwarded-proto') ?? request.nextUrl.protocol;
	urlObj.port = '';
	urlObj.host = redirectDomain;
	}
	return NextResponse.redirect(urlObj.toString());

... breaks domain-based routing when Next.js isn't running on standard HTTP/HTTPS port, and isn't behind a proxy.

For instance, when running a dev server (port 3000 by default, but could be anything), http://us-yourcompany-dev.localhost:3000/en-US/foobar will be redirected to 💥 http://us-yourcompany-dev.localhost/foobar 💥 when localePrefix: 'as-needed'. Whenever redirectDomain has a truthy value, the port will always be excluded. That works fine for the reported proxy issues and most website deployments, but not for deliberate use of alternative ports.

This one test:

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

Lines 2454 to 2466 in 59cd8dc

	it('uses the correct port and protocol when being called from an internal address', () => {
	middleware(
	createMockRequest('/', 'fr', 'http://192.168.0.1:3000', undefined, {
	'x-forwarded-host': 'ca.example.com',
	'x-forwarded-proto': 'https'
	})
	);
	expect(MockedNextResponse.next).not.toHaveBeenCalled();
	expect(MockedNextResponse.rewrite).not.toHaveBeenCalled();
	expect(MockedNextResponse.redirect.mock.calls[0][0].toString()).toBe(
	'https://ca.example.com/fr'
	);
	});

... would benefit from another to ensure that, in the absence of x-forwarded-host,¹ Next.js' port is preserved:

it('uses the correct port and protocol', () => { 
  middleware( 
    createMockRequest('/', 'fr', 'http://192.168.0.1:3000') 
  ); 
  expect(MockedNextResponse.next).not.toHaveBeenCalled(); 
  expect(MockedNextResponse.rewrite).not.toHaveBeenCalled(); 
  expect(MockedNextResponse.redirect.mock.calls[0][0].toString()).toBe( 
    'http://192.168.0.1:3000/fr' 
  ); 
});

Footnotes

1. Regarding x-forwarded-* headers, there's no standard for communicating the forwarding proxy's port: some append it to x-forwarded-host, others set a separate x-forwarded-port header. The forwarded header offers a standard (RFC-7239) way to include additional details like the port. ↩

[amannn]

@awkaiser-tr Thanks for digging into this and proposing a solution! I agree that it might be reasonable to assume that if there are no x-forwarded-* headers, then Next.js isn't running behind a reverse proxy. Would you be interested in adding a PR with your test and a proposed fix?

[awkaiser-tr]

@amannn sure! 🍻

[pepijn-vanvlaanderen]

@amannn interestingly enough, this 'fix' actually gives issues for us on Railway. Maybe a better solution would be to add it as a config somewhere.

[awkaiser-tr]

@pepijn-vanvlaanderen there are multiple patches related to this issue, can you be specific:

1. What version of next-intl are you using?
2. What issues are you experiencing? What would the simplest reproduction steps be?

[pepijn-vanvlaanderen]

Hi @awkaiser-tr, thanks for your reply. I have opened an issue here: #987