JWT authentication with a custom API

This package brings authentication to secure your private routes on your static sites build with the next export future from Next.js. Your custom API is used to handle the JWT authentication.

A JWT token is used for authentication and as a cookie refresh token.

• Authentication token gets stored in localStorage to access private routes and for authenticated API requests
• Refresh token is stored as a cookie

Installation

npm install --save next-auth-static-site

Configuration

You have to set a few environment variables to define your REST API endpoints. This can be done for example in .env.local or next.config.js.

Check the options reference for the configuration variables.

Usage

Implement the SessionProvider like this in your _app.js:

import { SessionProvider } from "next-auth-static-site";
import "./styles.css";

const App = ({ Component, pageProps: { ...pageProps } }) => {
  return (
    <SessionProvider>
      <Component {...pageProps} />
    </SessionProvider>
  );
};

export default App;

Now you can secure private/protected sites that requires authentication easily with useSession():

const { status, session, token } = useSession();

• status: Can be "loading", "authenticated" or "unauthenticated".
• session: Provides the session/user object returned from the login request.
  • If status is "loading", session will be undefined.
  • If status is "unauthenticated", session will be null.
  • If status is "authenticated", session will be object.
  • Provides the stored object returned from the login request (e.g. the username, email,...).
• token: Returns the current JWT auth token.

The /dashboard page is a private page example.

API requirements

next-auth-static-site will send some data to your API and awaits a specific answer.

It's up to you to handle all the requests on your API!

So you will need a few routes on your API:

• Login route
  • Bearer token
  • Refresh token
  • Body
• Refresh Route
• Logout route

An minimal example API with the required routes is included in this monorepo and is located in apps/api/.

Login route

POST /auth/login

This request body object (Content-Type: application/json) will be sent when performing the login request to the API:

{
  "email": "[email protected]",
  "password": "123456"
}

Handle the login request and on your API server and return on success:

• JWT auth token (with the header)
• JWT refresh token (as a cookie)
• Body with user data (for the session object, can be accessed by the client)

The JWT token must contain at least iat, exp and the user_id.

Bearer token

The API has to send the bearer token with the Authorization header:

Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...

Refresh token

Don't forget to set the JWT refresh token as a refresh_token cookie. Otherwise the client will be unauthenticated after the Bearer token expires because the token can't be refreshed.

Body

The Body content must be Content-Type: application/json and should contain some user data to display the values on the page. This could be changed, but the example uses email in a few components (dashboard.tsx page and authInfo.tsx component).

{
  "user_id": "userId",
  "email": "[email protected]"
}

Example response snippet from an express server:

res.setHeader("Access-Control-Expose-Headers", "Authorization");
res.setHeader("Authorization", "Bearer " + jwtToken);

res.cookie("refresh_token", jwtRefreshToken, {
  path: "/",
  maxAge: parseInt(process.env.JWT_REFRESH_TOKEN_LIFETIME) * 1000,
  httpOnly: true, // Client can't access this cookie with javascript
  sameSite: "Lax",
  secure: process.env.NODE_ENV === "production" ? true : false, // Forces to use https in production
});

res.status(200).json({ email: email, user_id: user_id });

Refresh route

GET /auth/refresh

Same as login, but you can skip the body object.

Return:

• Bearer token in the header
• Optional: replace/extend refresh token cookie

Logout Route

GET /auth/logout

• Clear the refresh_token cookie
• Any response error will delete the auth token stored in localStorage

Example

This monorepo provides a API and a web example:

• Web
• Web with i18n locale support
• API

Feel free to clone the monorepo and start the examples!

Install all dependencies:

npm ci

Start the development mode

npm run dev

Now you can access the web example on http://localhost:3000/ and the API will listen on port 5000.