App Router - next-auth route handler - How to access the Request BEFORE it is sent to NextAuth?

[simondpalmer]

Summary

Using next.js App Router - How do I access the Request BEFORE it is sent to NextAuth? I want to be able to replicate the following which is achievable with the next.js Pages Router:

// /api/auth/[...nextauth].js
import NextAuth from "next-auth"
import CredentialsProvider from "next-auth/providers/credentials"
import GoogleProvider from "next-auth/providers/google"

export default async function auth(req, res) {
  const providers = [
    CredentialsProvider({
      // ...
    }),
    GoogleProvider({
      // ...
    })
  ]

  // Based on https://next-auth.js.org/getting-started/rest-api#get-apiauthsignin
  const isDefaultSigninPage = req.method === "GET" && req.query.nextauth.includes("signin")
  if (isDefaultSigninPage) providers.pop()

  return await NextAuth(req, res, {
    providers,
    // rest of your config ...
  })
}

Additional information

For instance how can the following App Router - Route handler:

import NextAuth from "next-auth"

const handler = NextAuth({
  ...
})

export { handler as GET, handler as POST }

be adjusted to expose the Request similar to Pages Router like the following:

import type { NextApiRequest, NextApiResponse } from "next"
import NextAuth from "next-auth"

export default async function auth(req: NextApiRequest, res: NextApiResponse) {
  // Do whatever you want here, before the request is passed down to `NextAuth`
  return await NextAuth(req, res, {
    ...
  })
}

This is an extension to this issue
Originally posted by @balazsorban44 in #6792 (comment)

### Example

_No response_

[nalbertcerqueira]

I faced this issue sometime ago. For this case, i decided to rely on the pages router. It's not the best approach, but it worked for me.