pawol.nu/app/api/auth/[...nextauth]/route.js

import NextAuth from "next-auth"
import Credentials from "next-auth/providers/credentials"
import Twitter from "next-auth/providers/twitter"
import Google from "next-auth/providers/google"
import GitHub from "next-auth/providers/github"
import axios from "axios"

export const { handlers, auth } = NextAuth({
  providers: [
    Credentials({
      credentials: {
        username: {},
        password: {}
      },
      async authorize(credentials) {
        try {
          const user = await axios.post(
            `${process.env.NEXT_PUBLIC_API_URL}/auth/local`,
            {
              identifier: credentials.username,
              password: credentials.password
            }
          )

          return user.data || null
        } catch (error) {
          throw new Error(error.response?.data?.error?.message)
        }
      }
    }),
    Twitter({
      clientId: process.env.NEXT_PUBLIC_TWITTER_API_KEY,
      clientSecret: process.env.NEXT_PUBLIC_TWITTER_API_KEY_SECRET
    }),
    Google({
      clientId: process.env.NEXT_PUBLIC_GOOGLE_CLIENT_ID,
      clientSecret: process.env.NEXT_PUBLIC_GOOGLE_CLIENT_SECRET
    }),
    GitHub({
      clientId: process.env.NEXT_PUBLIC_GITHUB_CLIENT_ID,
      clientSecret: process.env.NEXT_PUBLIC_GITHUB_CLIENT_SECRET
    })
  ],
  session: {
    strategy: "jwt",
    trustHost: true
  },
  secret: process.env.NEXT_PUBLIC_JWT_SECRET,
  callbacks: {
    async jwt({ token, user, account }) {
      if (user && account) {
        let url = `${process.env.NEXT_PUBLIC_API_URL}/auth/${account.provider}/callback`

        if (account.provider === "twitter") {
          url += `?access_token=${account.oauth_token}&access_secret=${account.oauth_token_secret}`
        } else {
          url += `?access_token=${account.access_token}`
        }

        const response = await fetch(url)
        const data = await response.json()

        token.id = data.id || user.id
        token.jwt = data.jwt || user.jwt
        token.user = data.user || user.user
      }

      return token
    },
    async session({ session, token }) {
      session.jwt = token.jwt
      session.user = token.user
      return session
    }
  },
  pages: {
    signIn: "/pwopose",
    error: "/pwopose"
  }
})

export const { GET, POST } = handlers