Infinite redirect with middleware and basePath

Question 💬

I have a NextJS app setup to run under the /admin basepath. Whenever I use the middleware, I am having problems with it sending me to the wrong url for the login page. If I try passing a custom sign in page to the options, it redirects me infinitely. Can anyone point me in the right direction? Is this even possible?

How to reproduce ☕️

I am running next-auth@4.3.1, next@12.1.0

_app.js

import { SessionProvider } from 'next-auth/react';
import '../styles/globals.css';

function App({ Component, pageProps: { session, ...pageProps } }) {
  return (
    <SessionProvider
      session={session}
      basePath="/admin/api/auth"
    >
      <Component {...pageProps} session={session} />
    </SessionProvider>
  );
}

export default App;

_middleware.js

Note that without the custom signin page, the app redirects me to /api/auth/signin which does not exists (I can see the page if I manually go to /admin/api/auth/signin) and with the custom signin page I get an infinite redirect error.

import withAuth from 'next-auth/middleware';

export default withAuth({
  pages: {
    signIn: '/admin/signin',
  },
});

next.config.js

/** @type {import('next').NextConfig} */

const nextConfig = {
  reactStrictMode: true,
  env: {
    COGNITO_CLIENT_ID: '<removed>',
    COGNITO_CLIENT_SECRET: '<removed>',
    COGNITO_ISSUER: '<removed>',
    COGNITO_DOMAIN: '<removed>',
    NEXTAUTH_URL: 'http://localhost:3000/admin/api/auth',
    NEXTAUTH_SECRET: '<removed>',
  },
  basePath: '/admin',
};

module.exports = nextConfig;

pages/signin.js

import { Button } from '@mantine/core';
import { signIn } from 'next-auth/react';

export default function SignIn({ providers }) {
  return (
    <Button onClick={() => signIn('cognito')}>
      Sign in with Cognito
    </Button>
  );
}

pages/api/auth

import NextAuth from 'next-auth/next';
import CognitoProvider from 'next-auth/providers/cognito';

export default NextAuth({
  providers: [
    CognitoProvider({
      clientId: process.env.COGNITO_CLIENT_ID,
      clientSecret: process.env.COGNITO_CLIENT_SECRET,
      issuer: process.env.COGNITO_ISSUER,
      domain: process.env.COGNITO_DOMAIN,
    }),
  ],
  secret: process.env.NEXTAUTH_SECRET,
  debug: true,
});

Contributing 🙌🏽

No, I am afraid I cannot help regarding this

[Angeschossen]

I have the same issue by just using export { default } from "next-auth/middleware" in my middleware.

[ndom91]

@nicks6853 thanks for reaching out. So this should theoretically be possible. I was successfully able to recreate and reproduce your infinite refresh / forwarding problem.

I think I’ve boiled it down to packages/next-auth/src/next/middleware.ts:L65-L68 - this check isn’t being hit and so its not early returning. Therefore its continuing on until a few lines further down it appends another copy of the callbackUrl query param and redirect’s to the signInUrl over and over again…

Unfortunately I haven’t been abel to get any further tonight. I’ll take another look at this tomorrow 👍