log in as another user programmatically

[andrew-spg]

Hi,

I'm exploring building an internal tool that would allow our customer support team to log in as a user to help debug issues/bugs they're running into.

Has anyone built anything like this? Would appreciate pointers or examples!

I ran across #45 which definitely seems relevant, although it's not clear to me yet how to adapt this example for users who don't have a password (magic link login).

Thanks,
Andrew

[andrew-spg]

In case anyone else is running into this, here's how I did it for JWT:

  import jwt from "next-auth/jwt";
  import { set } from "next-auth/dist/server/lib/cookie";

  // ideally there would be a way to get the payload from a next-auth primitive
  const jwtPayload = {
    name: <user name>,
    email: <user email>,
    picture: <user picture>,
    sub: <user id>,
    ... // any additional fields you include in your jwt callback
  };
  const newEncodedJwt = await jwt.encode({
    secret: <your secret>,
    token: jwtPayload,
  });

  const cookieExpires = new Date();
  const maxAge = 30 * 24 * 60 * 60; // should be the same value you use in your NextApiHandler
  cookieExpires.setTime(cookieExpires.getTime() + maxAge);

  set(res, "next-auth.session-token", newEncodedJwt, {
    expires: cookieExpires.toISOString(),
  });

Not ideal but it works. This is modeled off the flow that happens here:

next-auth/src/server/routes/callback.js

Lines 181 to 197 in aacc34b

	if (useJwtSession) {
	const defaultJwtPayload = {
	name: user.name,
	email: user.email,
	picture: user.image,
	sub: user.id?.toString()
	}
	const jwtPayload = await callbacks.jwt(defaultJwtPayload, user, account, profile, isNewUser)
	// Sign and encrypt token
	const newEncodedJwt = await jwt.encode({ ...jwt, token: jwtPayload })
	// Set cookie expiry date
	const cookieExpires = new Date()
	cookieExpires.setTime(cookieExpires.getTime() + (sessionMaxAge * 1000))
	cookie.set(res, cookies.sessionToken.name, newEncodedJwt, { expires: cookieExpires.toISOString(), ...cookies.sessionToken.options })