Adding SignUp callback

[zanzlender]

I have been using NextAuth in a lot of my projects lately and faced some weird challenges while doing so. For example when I have multiple providers, or combined with credentials etc.

Usually what I want to do with my app is something like this:

LOGIN PAGE

• user clicks on google login
• check if this user is in my database (registered)
• if registered --> signIn
• if not --> save to db (register), then signIn

It all works great 👍 but it gets kinda messy putting all that logic in, especially because different providers need different logic etc. I don't know if this has been asked before, but is it possible do add a SignUp function? It doesn't need to do anything special, it would just be for defining the SignUp callback logic and decoupling it from the SignIn logic.

Then my flow would be something like this:

LOGIN PAGE

• user clicks on google login (SignIn)
• check if this user is in my database
• if registered --> signIn
• if not --> display "User not found"

REGISTRATION PAGE

• user clicks on register with google (SignUp())
• check if this user is in my database
• if registered --> display "User already exists"
• if not --> register user, then signIn

[paulegradie]

Was this ever implemented? There is a SignUp page in the configuration object, but there is no signUp callback. That would be very handy to do thigns such as pre-populate an account with some data when they first create their account. Its particualy important for single-click sign up, e.g. when using one of the database adapters (e.g. the PrismaAdapter).

Definitely a no-brainer feature to live somewhere amongst the auth. 👍

[KModestas]

yes please

[zanzlender]

This is implemented when creating/using an adapter, it should have a createUser function that is called when a new user tries to log in. read here

And also, the pages object has a newUser property where you can redirect him when he registers to do w/e you want. E.g. you could redirect to an api that will redirect to the page you want, or redirect directly to that page. Auth docs

However, I couldn't find anywhere in the docs when exactly that callback is fired. E.g. does the adapter immediately query for the user data in db, and if nothing is found automatically calls createUser, or maybe something else... Or rather it does say User creation in the database is automatic and happens when the user is logging in for the first time with a provider, however, it doesn't mention how they check for that specifically...

[JoshPav]

For anyone looking for a workaround, you can get something without too much effort by wrapping the default methods of your desired adapater.

Here's a rough example of how I've got a signUp callback working with the MongoDBAdapter.

// /api/auth/[...nextauth]/route.ts

...

const DBAdapter = MongoDBAdapter(clientPromise)

export const authOptions: AuthOptions = {
    /* Your other options here */
    adapter: {
        ...DBAdapter,
        createUser: (async user) => {

            // Using non-null assertion as according to NextAuth this method is requried.  
            const createdUser = await DBAdapter.createUser!(user)
            
            // Run whatever callbacks you want here
            prePopulateUserData(createdUser); 

            return createdUser;
        }
    },
}

Of course you can extend this to work for all the other methods used by your Adapter. Hope this is of use to some others!

[andresgutgon]

This is super nice. Thanks

[zgababa]

Nice, but how do you handle redirect ? I would like to redirect new users on /welcome for example.

[imyuanli]

这是自动回复的邮件。您好，我最近正在休假中，无法亲自回复你的邮件。我将在假期结束后，尽快给你回复。

[andresgutgon]

yes