Rewrites with i18n

[Aviortheking]

What version of Next.js are you using?

11.1.2 and 11.1.3-canary.14

What version of Node.js are you using?

14 and 16

What browser are you using?

Chrome Firefox Insomnia

What operating system are you using?

Windows, Linux

How are you deploying your application?

Vercel

Describe the Bug

It seems that we cant run POST requests while using i18n on the latest version (it was working on 11.0.x and 11.1.0 but not 11.1.1+)

• I tried running my request without i18n and it worked
• I tried running my request with i18n but it stopped working
• I tried adding/removing the basePath option nothing changed

Expected Behavior

request shouuld be rewrote to the other path

To Reproduce

Minimal Github repository

https://github.com/Aviortheking/tests-nextjs

[alexbchr]

Is it possible to prioritize this issue? Rewrites not working when i18n is enabled is a pretty big issue according to me. Rewrites are especially useful for i18n projects, as it lets you group pages in folders and rewrite those folder names depending on the locale of the user. Otherwise, the only way to do so is using Dynamic Routing, but you can't have 2 dynamic routes at the same level in a folder structure, which makes it non-viable for us in the projects we are working on, as most pages are rendered in a Catch-all dynamic route, so our folder structure looks like:

pages/
  [[...slug]].tsx
  /reserver
      index.ts

If we want the /reserver path (in FR) to be /book in EN, we have no choice but to use rewrites, as using a dynamic route here, such as [bookSlug]/index.ts do weird things with Next.js before of the catch-all route.

I got here after finding the issue #28863

I have exactly the same problem... The rewrites work fine for me locally or when doing next build && next start, but they don't work at all once deployed on Vercel. Tried using locale: false, basePath: false (even though we are not using the basePath feature).

[noblica]

We're experiencing the same issue. I've also tried it with next v12, but the issue perssits. As the person above me described, it only happens when deploying to vercel. Locally the production build works fine.

[GiancarlosIO]

Same here, we just configured i18n.locales and now all of our api rewrites give us 404 errors.
It works in local but not in vercel 🤔

[raphaelHuerzeler]

We've also run into this issue:

• we use i18n
• we do have a [...alias].tsx catch all route
• we use rewrites to talk to our backend:

{
   source: `/api/${TENANT}/:path*`,
   destination: `${host}/api/${TENANT}/:path*`,
},

• all backend requests are POST
• up to and including nextjs 11.0.1 everything worked fine (we have several production environments running on this)
• on any newer version the backend request fail, this is exclusive to vercel environment, we've tried amplify a while back and the issue didn't occur.
• on a hunch i tried changing the rewrites to, which interestingly enough worked:

{
   source: `/backend/${TENANT}/:path*`,
   destination: `${host}/api/${TENANT}/:path*`,
},

So it seems the issue is a combination of:

• vercel environment
• i18n
• POST request to a rewrite
• having a catch-all route i.e. /[...alias].tsx in our case
• a rewrite using /api route (although other comments in this thread seem to suggest this also happens in other scenarios)
• also note that we do NOT have any wildcard routes under /api

All of the deploys below use the exact same codebase (except for nextjs version and next.config.js refconfiguration) and backend.

Deploy (next12.0.7) where dispatcher uses /api and fails (note x-matched-path: //[...alias] in dispatcher response):
https://spectra-whitelabel-dlh5epbbq-deep-impact.vercel.app/en

Deploy (next12.0.7) where dispatcher uses /backend and works:
https://spectra-whitelabel-fh2e0kxc6-deep-impact.vercel.app/en

For completeness sake heres also a deploy with next11.0.1 where /api calls work:
https://spectra-whitelabel-oygahxlxw-deep-impact.vercel.app/en

While the workaround can be made to work as described it's still problematic for some of our tenants as some also use 3rd party integrations that make use of the existing /api rewrites.

[chrisui]

Same issue here with /auth/[...nextauth].ts inside /api and a /api/graphql beforeFiles rewrite to an external api. Works locally, fails in vercel.

[MathieuAA]

It also happens with apps not deployed to Vercel :( this is a blocker

[I-Valchev]

Same issue here with /auth/[...nextauth].ts inside /api and a /api/graphql beforeFiles rewrite to an external api. Works locally, fails in vercel.

Same issue here with re-routing to an external API.

[lswainemoore]

I am in the same boat--rewrites working fine with i18n except for POSTs prefixed with /api/, and even then it only 404s once deployed. Does anyone more next.js savvy than me have any idea where to start to look for this bug? I'd gladly take a stab at it, if I had a sense of where to begin.

[noblica]

I am in the same boat--rewrites working fine with i18n except for POSTs prefixed with /api/, and even then it only 404s once deployed. Does anyone more next.js savvy than me have any idea where to start to look for this bug? I'd gladly take a stab at it, if I had a sense of where to begin.

I think this is more of a vercel bug, than a next.js bug.

[lswainemoore]

I think this is more of a vercel bug, than a next.js bug.

That makes sense, though complicated slightly by reports in this thread that it's also a problem hosting elsewhere. Regardless, if it's not a next.js bug, are we discussing it in the right place?

[ghost]

We have the same issue, with the following config

  i18n: {
    locales: ['en', 'es'],
    localeDetection: false,
  },
  async rewrites() {
    return [
      {
        source: '/my/path/:slug*',
        destination: '/my/other-path/:slug*',
      },
    ]
  },

with i18n object the rewrite does not work, without it works fine

[balazsorban44]

I could recreate this here, even using canary and a minimalized i18n config: https://github.com/balazsorban44/nextjs-28921

We will look into this.

[ijjk]

Hi, this has been updated in v12.1.1-canary.6 of Next.js, please update and give it a try!

[github-actions]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.