Using Directus with Next-Auth to handle authentication in your frontend.

For your information, you can handle the authentication in your app without Next-Auth, and using Directus sdk as shown here.

The rest of this tutorial has been tested with directus 9.18.2, directus js-sdk 10.1.4, and Next.js 12.3.1 and next-auth 4.15.0.

Main context

When building my SaaS app with Next.js and Directus I had a hard time figuring out how to use Next-Auth and Directus sdk for authentication. In the end, I find a solution for both of them, but not using them at the same time.

I have already shown how to configure the Directus sdk method. Now I will show you the method I use for my app, which relies on Next-Auth.

Table of Contents

Main context
Configuration of [...nextauth].js
Handling token rotation
The main problem
The solution

Configuration of [...nextauth].js

Please note that directus send you variables that are snake case like: access_token. So, to keep homogeneity in my app, I transformed them in accessToken when storing them.

Also, one big mistake I made at first for this configuration was to use a jwt secret that was different from the main NEXTAUTH_SECRET.

Something like:

[...nextauth].js

// JSON Web Token Options
{
  jwt: {
    secret: process.env.JWT_SECRET,
    encryption: true,
  },
}

This is not useful and made me unable to use Next.js middleware. See Binding Directus auth and Next.js middleware to protect your app. for how to use Next.js middleware and Next-Auth to secure your app.

Here is my new configuration which handle token rotation.

[...nextauth].js

import NextAuth from "next-auth/next";
import CredentialsProvider from "next-auth/providers/credentials";
import { signIn } from "next-auth/react";

const pubAPI = process.env.DIRECTUS_PUBLIC_API;

export const options = {
  providers: [
    CredentialsProvider({
      name: "Credentials",
      credentials: {
        email: { label: "Email", type: "text" },
        password: { label: "Mot de passe", type: "password" },
      },
      async authorize(credentials, req) {
        const payload = {
          email: credentials.email,
          password: credentials.password,
        };
        const res = await fetch(pubAPI + "auth/login", {
          method: "POST",
          body: JSON.stringify(payload),
          headers: { "Content-Type": "application/json" },
          credentials: "include",
        });
        const user = await res.json();

        if (!res.ok) {
          throw new Error("Email ou mot de passe incorrect.");
        }

        if (res.ok && user) {
          return user;
        }

        return null;
      },
    }),
  ],
  session: {
    jwt: true,
  },
  callbacks: {
    async jwt({ token, user, account }) {
      if (account && user) {
        return {
          ...token,
          accessToken: user.data.access_token,
          expires: Date.now() + user.data.expires,
          refreshToken: user.data.refresh_token,
          error: user.data.error,
        };
      }

      if (Date.now() < token.expires) {
        return token;
      }

      const refreshed = await refreshAccessToken(token);
      return await refreshed;
    },

    async session({ session, token }) {
      session.user.accessToken = token.accessToken;
      session.user.refreshToken = token.refreshToken;
      session.user.expires = token.expires;
      session.user.error = token.error;

      return session;
    },
  },
  secret: process.env.NEXTAUTH_SECRET,
  pages: {
    signIn: "/sign-in",
  },
  debug: true,
};

async function refreshAccessToken(token) {
  try {
    const response = await fetch(pubAPI + "auth/refresh", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ refresh_token: token.refreshToken }),
      credentials: "include",
    });

    const refreshedTokens = await response.json();

    if (!response.ok) {
      signIn();
    }

    if (response.ok && refreshedTokens) {
      return {
        ...token,
        accessToken: refreshedTokens.data.access_token,
        expires: Date.now() + refreshedTokens.data.expires,
        refreshToken: refreshedTokens.data.refresh_token,
      };
    }
  } catch (error) {
    console.log(
      new Date().toUTCString() + " Error in refreshAccessToken:",
      error
    );

    return {
      ...token,
      error: "RefreshAccessTokenError",
    };
  }
}

const nextauthfunc = (req, res) => NextAuth(req, res, options);

export default nextauthfunc;

Handling token rotation

The main problem

One of the problem, in my opinion, that made me almost give up on Next-Auth is the token rotation. Many times, I wanted a function like refreshToken() in my client side.

Indeed, when using multiple components, each one with a fetch inside, you might end up with the case of this timeline:

T1: component 1 fetches something
T2: time to refresh token -> fetch for refreshing token
T3: component 2 fetches something
T4: component 1 receives OK response
T5: refreshed token received
T6: component 2 receives an error

This happened because the server had a new token for my user at the time the request for component 2 was received with the former token. Nonetheless, the request (made with a useSWR() function in my case) kept firing with the former token which was cached apparently.

The solution

The solution to handle the token rotation properly comes partly from this post.

It is based on two things: first, a component that times the expiration date of your token and calls for a refresh before. A catch for 401 errors that might still happen during the refresh.

I let you read Mateusz Baranowski's solution for creating a <RefreshTokenHandler setInterval={setInterval} /> component.

For the error processing, since I use SWR for my part, in the error processing I catch 401 errors and make them look like the loading of my component.

aUserDetailComponent.js

import { useUserDetails } from "../../api/queries/getUser";
import FormUserDetail from "./formDetails";
import { useSession } from "next-auth/react";

export default function UserDetails() {
  const { data: session, status } = useSession({
    required: true,
  });
  const { userDetails, error, isLoading, mutate } = useUserDetails(
    session?.user?.accessToken
  );
  if (error) {
    if (error.status === 401) return "Loading";
    return "Error";
  }
  if (isLoading) return "Loading";

  return (
    <FormUserDetail
      userDetails={userDetails?.data?.customer_details[0]}
      mutate={mutate}
    />
  );
}

If you have better implementation for authentication and refreshing token, I would be more than happy to hear about them :)