`basePath` does not work with `urlMappingStrategy: "rewrite"` in `app` router

[setowilliam]

Describe the bug When using the next-app example, using basePath with urlMappingStrategy: "rewrite" redirects to not-found page when navigating to http://localhost:3000/base.

To Reproduce Steps to reproduce the behavior:

1. Set basePath in locales/client.ts to /base
2. Set basePath in next.config.js to /base
3. Set urlMappingStrategy in middleware.ts to rewrite
4. Start dev server
5. Go to http://localhost:3000/base
6. not-found screen is shown

Expected behavior From the description of rewrite:

rewrite: https://example.com/products -> rewrite to https://example.com/en/products -> client doesn't see the locale in the url

I would expect that navigating to http://localhost:3000/base would rewrite to http://localhost:3000/base/en.

Screenshots

About (please complete the following information):

• next-international 1.1.3
• Next.js 13.5.4

[QuiiBz]

Good catch, we'll probably need to introduce a new basePath option to createI18nMiddleware. In the meantime, you could use the default urlMappingStrategy. Not ideal but I'll try to fix this bug asap.

[yukiyohure]

@QuiiBz I came across the same Issue. I believe this library is one of the few libraries that meet the need for the Next.js app router users to "do not want to change the url structure by introducing i18n feature into our app". So I hope this Issue will be fixed as soon as possible.