Build a Fullstack App from Scratch V2 (feat Next.js)

JSON Web Tokens

We'll be using JWT's for auth. Let's create some methods for handling them in the same /lib/auth.ts.

Create a JWT:

export const createJWT = (user) => {
  // return jwt.sign({ id: user.id }, 'cookies')
  const iat = Math.floor(Date.now() / 1000);
  const exp = iat + 60 * 60 * 24 * 7;

  return new SignJWT({ payload: { id: user.id, email: user.email } })
    .setProtectedHeader({ alg: "HS256", typ: "JWT" })
    .setExpirationTime(exp)
    .setIssuedAt(iat)
    .setNotBefore(iat)
    .sign(new TextEncoder().encode(process.env.JWT_SECRET));
};

Validate a JWT:

export const validateJWT = async (jwt) => {
  const { payload } = await jwtVerify(
    jwt,
    new TextEncoder().encode(process.env.JWT_SECRET)
  );

  return payload.payload as any;
};

Getting the JWT from cookies:

export const getUserFromCookie = async (cookies) => {
  const jwt = cookies.get(process.env.COOKIE_NAME);

  const { id } = await validateJWT(jwt.value);

  const user = await db.user.findUnique({
    where: {
      id: id as string,
    },
  });

  return user;
};