Inconsistent behaviour of `request.nextUrl.href`

What version of Next.js are you using?

12.0.4

What version of Node.js are you using?

16.13.0

What browser are you using?

Chrome

What operating system are you using?

macOS

How are you deploying your application?

next start

Describe the Bug

I’m attempting to use Middleware to force a default locale in my application URLs, using example code from the documentation.

This worked when accessing the application through localhost, but when accessing using any other hostname, request.nextUrl.href contains the full URL. I’m not sure whether this is expected behaviour, but it seems like it could be a bug as this breaks the example code provided in the documentation.

Expected Behavior

For request.nextUrl.href to behave consistently. Either return the full URL, or the application path. Ideally the latter, as the example indicates this would be expected behaviour.

To Reproduce

Take this simple middleware:

import type { NextFetchEvent, NextRequest } from 'next/server'

export function middleware(request: NextRequest, event: NextFetchEvent) {
  return new Response(request.nextUrl.href)
}

curl the app using localhost, see the following:

$ curl http://localhost:3000/hello
/hello

But when using any other IP or hostname:

$ curl http://127.0.0.1:3000/hello
https://127.0.0.1:3000/hello

[marcoacierno]

This doesn’t seem to be fixed @Kikobeats? I am using next@12.0.7 and on Vercel req.nextUrl.href seems to be an absolute URL while it is a relative URL on Localhost

I am using: https://nextjs.org/docs/advanced-features/i18n-routing#prefixing-the-default-locale

export function middleware(req: NextRequest, _ev: NextFetchEvent) {
  const shouldHandleLocale =
    !PUBLIC_FILE.test(req.nextUrl.pathname) &&
    !req.nextUrl.pathname.includes("/api/") &&
    req.nextUrl.locale === "default";
  const locale = getLocale(req.cookies.pyconLocale);

  console.log("req.nextUrl.href =>", req.nextUrl.href)
  return shouldHandleLocale
    ? NextResponse.redirect(`/${locale}${req.nextUrl.href}`)
    : undefined;
}

const getLocale = (cookie: string): string => {
  if (cookie && VALID_LOCALES.findIndex((e) => e === cookie) !== -1) {
    return cookie;
  }

  return DEFAULT_LOCALE;
};

Going to https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/ redirects tohttps://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/enhttps:/pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/default

This is the code:

• https://github.com/pythonitalia/pycon/pull/2525/files#diff-e064de65d4610383e665a32e7e32ee1f520c466a6a63ecea8925ff8337f08215R21
• https://github.com/pythonitalia/pycon/pull/2525/files#diff-7a57dd0b93a2d5540e0693d3b430820e5460baf6b79872471e25cc41811ef90cR8

More:

  ~/projects/pycon/backend on   WEB-167-use-nextjs-intl-system *12 !4 ❯ curl -I https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/
HTTP/2 302
date: Sun, 05 Dec 2021 13:02:41 GMT
content-type: text/plain
x-robots-tag: noindex
location: /enhttps:/pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/default
server: Vercel
x-vercel-id: fra1::mjftx-1638709361021-e0c75daacf94
strict-transport-security: max-age=63072000; includeSubDomains; preload
cache-control: public, max-age=0, must-revalidate
x-vercel-cache: MISS

====

Logs from Vercel

req.nextUrl.href => https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/default

req.nextUrl:

{ 
    hash: '',  
    searchParams: {},  
    search: '',  
    pathname: '/default'
    port: ''
    hostname: 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app'
    host: 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app'
    password: ''
    username: ''
    protocol: 'https:'
    origin: 'https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app'
    href: 'https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/default'
    _options:    { basePath: ''
       headers:       { accept: '*/*'
          'accept-encoding': 'gzip, deflate, br'
          'accept-language': 'en-GB,it;q=0.5'
          'cf-ew-script-hash': '1.769f1d7b3e1996f0801f1e96cec9104ebf83819678da4655e3a9022e2a520aec.vercel'
          connection: 'Keep-Alive'
          cookie: 'pyconLocale=default'
          'deployment-url': 'pycon-cdkb50fs9-python-italia.vercel.app'
          forwarded: 'for=152.37.76.72;host=pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app;proto=https'
          'forwarded-for': '152.37.76.72'
          host: 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app'
          'max-duration': '5000'
          referer: 'https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/enhttps:/pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/default'
          'sec-fetch-dest': 'empty'
          'sec-fetch-mode': 'cors'
          'sec-fetch-site': 'same-origin'
          'user-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:94.0) Gecko/20100101 Firefox/94.0'
          'x-forwarded-for': '152.37.76.72'
          'x-forwarded-host': 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app'
          'x-forwarded-proto': 'https'
          'x-middleware-preflight': '1'
          'x-real-ip': '3.8.152.17'
          'x-vercel-edge-region': 'lhr'
          'x-vercel-id': 'lhr1::qrz77-1638709680500-32d798092336'
          'x-vercel-ip-city': 'Hendon'
          'x-vercel-ip-country': 'GB'
          'x-vercel-ip-country-region': 'ENG'
          'x-vercel-ip-latitude': '51.5943'
          'x-vercel-ip-longitude': '-0.2491' }
       i18n:       { locales: [Object]
          defaultLocale: 'default'
          localeDetection: false }
       trailingSlash: undefined }
    _basePath: ''
    _url:    { 
        hash: '',
       searchParams: {},
       search: '',
       pathname: '/',
       port: '',
       hostname: 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app',
       host: 'pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app',
       password: '',
       username: '',
       protocol: 'https:',
       origin: 'https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app',
       href: 'https://pycon-git-web-167-use-nextjs-intl-system-python-italia.vercel.app/,
    },  
       _locale:    { path: { pathname: '/', detectedLocale: 'default' }
       domain: undefined,
       defaultLocale: 'default',
       locale: 'default',
       redirect: undefined,
       trailingSlash: false,
    } 
}

In case it helps anyone:

export function middleware(req: NextRequest, _ev: NextFetchEvent) {
  const shouldHandleLocale =
    !PUBLIC_FILE.test(req.nextUrl.pathname) &&
    !req.nextUrl.pathname.includes("/api/") &&
    req.nextUrl.locale === "default";
  const locale = getLocale(req.cookies.pyconLocale);

  return shouldHandleLocale
    ? NextResponse.redirect(`/${locale}${req.nextUrl.pathname.replace("/default", "")}`)
    : undefined;
}

this is what I did to fix the middleware code: req.nextUrl.pathname.replace("/default", "")

[ndavidson-manticore]

I agree that this issue is not closed out and was wrongly marked as such. I am still having inconsistent behavior with the request nextUrl object and even the request.url string. @Kikobeats