Auth.js Multi-Tenant

.env

AUTH_TRUST_HOST=true

auth.ts

// https://domain.com = our own, non-multi-tenant domain

const getSiteUrl = (req?: NextRequest) => {
  if (!req) {
      return undefined;
  }

  const { headers } = req;
  const host = headers.get('X-Forwarded-Host'); // a tenant subdomain or tenant's own domain
  const proto = headers.get('X-Forwarded-Proto');

  return (host && proto) ? `https://${host}` : 'https://domain.com';
};


export const {
  auth, handlers, signIn, signOut, unstable_update: update,
} = {
  basePath: '/api/auth',
  baseUrl: (r) => getSiteUrl(r) ?? 'https://domain.com',
  trustHost: true,
  providers: [
    GitHub({
        clientId: process.env.GITHUB_CLIENT_ID ?? '',
        clientSecret: process.env.GITHUB_CLIENT_SECRET ?? '',
        authorization: {
            params: { scope: 'user:email' },
        },
        redirectProxyUrl: 'https://domain.com/api/auth',
    }),
  ],
};

package.json

{
  "dependencies": {
    "next-auth": "npm:next-auth-chrysus@^5.0.0-beta.23"
  }
}