Best way to fetch and add user roles from database to session

[Pawel1894]

Hey!

I have setup t3 app with nextAuth + trpc. I'm wondering what is best practice to assign user roles to session in nextAuth config, as I don't want to do refetch on every endpoint?

As I understand in this setup I use databse strategy so JWT callback won't work?
Should I just put this fetch inside Session callback or somewhere else? I'm scared that it will be fired too much, I'm not sure how offten session is checked -> https://next-auth.js.org/configuration/callbacks#session-callback. Tried to find an example or some info on it in docs and google but could not.

Is it even a good direction? Or is it better to check if user is an admin for specific endpoint or in my case create special procedure for trpc?

This is my nextauth config:

import { type DefaultSession, type NextAuthConfig } from "next-auth";
import DiscordProvider from "next-auth/providers/discord";

import { db } from "@/server/db";

/**
 * Module augmentation for `next-auth` types. Allows us to add custom properties to the `session`
 * object and keep type safety.
 *
 * @see https://next-auth.js.org/getting-started/typescript#module-augmentation
 */
declare module "next-auth" {
  interface Session extends DefaultSession {
    user: {
      id: string;
    } & DefaultSession["user"];
  }

  // interface User {
  //   // ...other properties
  //   // role: UserRole;
  // }
}

/**
 * Options for NextAuth.js used to configure adapters, providers, callbacks, etc.
 *
 * @see https://next-auth.js.org/configuration/options
 */
export const authConfig = {
  providers: [
    DiscordProvider,
    /**
     * ...add more providers here.
     *
     * Most other providers require a bit more work than the Discord provider. For example, the
     * GitHub provider requires you to add the `refresh_token_expires_in` field to the Account
     * model. Refer to the NextAuth.js docs for the provider you want to use. Example:
     *
     * @see https://next-auth.js.org/providers/github
     */
  ],
  adapter: PrismaAdapter(db),
  callbacks: {
    session: ({ session, user }) => {
      return {
        ...session,
        user: {
          ...session.user,
          id: user.id,
        },
      };
    },
  },
} satisfies NextAuthConfig;