bewcloud/pages/api/auth/multi-factor/passkey/begin.ts

import page, { RequestHandlerParams } from '/lib/page.ts';
import { PublicKeyCredentialCreationOptionsJSON } from '@simplewebauthn/server';

import { PasskeyModel } from '/lib/models/multi-factor-auth/passkey.ts';
import { UserModel } from '/lib/models/user.ts';
import { AppConfig } from '/lib/config.ts';

export interface RequestBody {
  email: string;
}

export interface ResponseBody {
  success: boolean;
  error?: string;
  options?: PublicKeyCredentialCreationOptionsJSON;
  sessionData?: {
    challenge: string;
    methodId: string;
  };
}

async function post({ request }: RequestHandlerParams) {
  const isMultiFactorAuthEnabled = await AppConfig.isMultiFactorAuthEnabled();

  if (!isMultiFactorAuthEnabled) {
    const responseBody: ResponseBody = {
      success: false,
      error: 'Passwordless passkey login requires multi-factor authentication to be enabled.',
    };

    return new Response(JSON.stringify(responseBody), { status: 403 });
  }

  const body = await request.clone().json() as RequestBody;
  const { email } = body;

  if (!email) {
    const responseBody: ResponseBody = {
      success: false,
      error: 'Email is required',
    };

    return new Response(JSON.stringify(responseBody), { status: 400 });
  }

  const user = await UserModel.getByEmail(email);

  if (!user) {
    const responseBody: ResponseBody = {
      success: false,
      error: 'User not found',
    };

    return new Response(JSON.stringify(responseBody), { status: 404 });
  }

  const config = await AppConfig.getConfig();
  const allowedCredentials = PasskeyModel.getCredentialsFromUser(user);

  if (allowedCredentials.length === 0) {
    const responseBody: ResponseBody = {
      success: false,
      error: 'No passkeys registered for this user',
    };

    return new Response(JSON.stringify(responseBody), { status: 400 });
  }

  const options = await PasskeyModel.generateAuthenticationOptions(
    config.auth.baseUrl,
    allowedCredentials,
  );

  const responseBody: ResponseBody = {
    success: true,
    options,
    sessionData: {
      challenge: options.challenge,
      methodId: options.challenge,
    },
  };

  return new Response(JSON.stringify(responseBody));
}

export default page({
  post,
  accessMode: 'public',
});