Generic OAuth SSO (server side) in sveltekit

# hooks.server.ts

import { auth, checkSession } from "$lib/server/auth";
import { type Handle } from "@sveltejs/kit";
import { sequence } from "@sveltejs/kit/hooks";
import { svelteKitHandler } from "better-auth/svelte-kit";

const handleAuth: Handle = async ({ event, resolve }) => {
  return svelteKitHandler({ event, resolve, auth });
};

export const handleRouting: Handle = async ({
  event,
  resolve
}) => {
  const session = await checkSession(event);
  if (!session) await auth.api.signInWithOAuth2({ body: { providerId: "example-provider-id", callbackURL: "https://localhost:5173" } })
  return resolve(event);
};


export const handle: Handle = sequence(
  handleAuth,
  handleRouting
);

auth.ts

import type { RequestEvent } from "@sveltejs/kit";
import { betterAuth } from "better-auth"
import { genericOAuth } from "better-auth/plugins"

export const auth = betterAuth({
  plugins: [
    genericOAuth({
      config: [
        {
          providerId: "example-provider-id",
          clientId: "---",
          clientSecret: "---",
          discoveryUrl: "---",
        },
      ]
    })
  ]
})

export async function checkSession(e: RequestEvent) {
  const session = await auth.api.getSession({
    headers: e.request.headers
  });
  return session;
}