nuxt-app/server/api/auth/oauth/[provider]/callback.get.ts

import log4js from "logger";
import { oauthManager } from '#server/service/oauth/oauth-manager';
import { setSessionCookie } from '#server/service/auth/cookie';
import { OAuthError } from '#server/service/oauth/oauth-error';
import { FRONTEND_LOGIN_PATH } from "common/config"

const logger = log4js.getLogger("OAUTH");

export default defineWrappedResponseHandler(async (event) => {
  const providerName = getRouterParam(event, 'provider');
  const query = getQuery(event);

  const { code, state } = query as { code?: string; state?: string };

  logger.info(`[callback] Received callback: provider=${providerName}, hasCode=${!!code}, hasState=${!!state}`);

  if (query.error) {
    logger.warn(`[callback] Provider returned error: ${query.error}, description=${query.error_description ?? '-'}`);
  }

  if (!code || !state) {
    logger.warn(`[callback] Missing params: code=${!!code}, state=${!!state}`);
    return sendRedirect(event, `${FRONTEND_LOGIN_PATH}?oauth_error=missing_params`);
  }

  try {
    const result = await oauthManager.handleCallback(providerName!, code, state);

    if (result.sessionId) {
      setSessionCookie(event, result.sessionId);
    }

    logger.info(`[callback] Success: provider=${providerName}, isNewUser=${result.isNewUser}, hasSession=${!!result.sessionId}`);
    return sendRedirect(event, `${FRONTEND_LOGIN_PATH}?oauth_success=1`);
  } catch (error) {
    const errorCode = error instanceof OAuthError ? error.code : 'OAUTH_UNKNOWN';
    logger.error(`[callback] Failed: provider=${providerName}, errorCode=${errorCode}`, error);
    return sendRedirect(event, `${FRONTEND_LOGIN_PATH}?oauth_error=${errorCode}`);
  }
});