@yohangel / auth-express

1.0.0 ▾

1.0.0

MIT

GitHub

Express 5용 Better Auth: 인증 라우트 마운트와 requireAuth로 API 보호

코드파일 3개컨텍스트약 405토큰검사 통과

약 405토큰→ src/lib/auth-express/AGENTS.md→ .cursor/rules/genpm-yohangel-auth-express.mdc

이것이 AI가 src/lib/auth-express에서 작업할 때 읽는 내용 그대로입니다. 그 외에는 컨텍스트에 아무것도 추가되지 않습니다.

@yohangel/auth-express — rules for AI agents

Purpose

Connects @yohangel/auth to Express 5: mounts Better Auth on /api/auth/* and provides requireAuth / optionalAuth middleware that put the session in res.locals.

Module map

index.ts — mountAuth(app, opts), requireAuth, optionalAuth, AuthLocals type, createAuth re-export.

Integration (do this after installing)

Order matters — mount auth BEFORE body parsers:

import express from 'express';
import { mountAuth, requireAuth } from './lib/auth-express/index.js';
const app = express();
mountAuth(app, { sendEmail });          // /api/auth/*
app.use(express.json());
app.get('/api/me', requireAuth, (req, res) => res.json({ id: res.locals.user.id }));

Frontend on another origin: app.use(cors({ origin: ['https://app.example.com'], credentials: true })) before mountAuth, and list that origin in AUTH_TRUSTED_ORIGINS.
Behind a proxy/CDN set app.set('trust proxy', 1) and AUTH_IP_HEADER so rate limits use the real client IP.
Express 4 is not supported (route syntax *splat is Express 5). Project must be ESM ("type": "module").

Conventions

Protect routes with requireAuth; read res.locals.user / res.locals.session (typed by AuthLocals).
Authorization (who can do what) goes in your handlers after requireAuth, never on the client.

Don't

Don't put express.json() before mountAuth (Better Auth must read the raw body).
Don't use cors({ origin: '*', credentials: true }).
Don't return res.locals.session (contains the token) to the client.

# @yohangel/auth-express — rules for AI agents

## Purpose
Connects `@yohangel/auth` to Express 5: mounts Better Auth on `/api/auth/*` and provides `requireAuth` / `optionalAuth` middleware that put the session in `res.locals`.

## Module map
- `index.ts` — `mountAuth(app, opts)`, `requireAuth`, `optionalAuth`, `AuthLocals` type, `createAuth` re-export.

## Integration (do this after installing)
1. Order matters — mount auth BEFORE body parsers:
   ```ts
   import express from 'express';
   import { mountAuth, requireAuth } from './lib/auth-express/index.js';
   const app = express();
   mountAuth(app, { sendEmail });          // /api/auth/*
   app.use(express.json());
   app.get('/api/me', requireAuth, (req, res) => res.json({ id: res.locals.user.id }));
   ```
2. Frontend on another origin: `app.use(cors({ origin: ['https://app.example.com'], credentials: true }))` before `mountAuth`, and list that origin in `AUTH_TRUSTED_ORIGINS`.
3. Behind a proxy/CDN set `app.set('trust proxy', 1)` and `AUTH_IP_HEADER` so rate limits use the real client IP.
4. Express 4 is not supported (route syntax `*splat` is Express 5). Project must be ESM (`"type": "module"`).

## Conventions
- Protect routes with `requireAuth`; read `res.locals.user` / `res.locals.session` (typed by `AuthLocals`).
- Authorization (who can do what) goes in your handlers after `requireAuth`, never on the client.

## Don't
- Don't put `express.json()` before `mountAuth` (Better Auth must read the raw body).
- Don't use `cors({ origin: '*', credentials: true })`.
- Don't return `res.locals.session` (contains the token) to the client.

.genpmignore 적용 후 주입될 정확한 트리입니다. 고정 대상:

src/lib/auth-express/index.ts읽기 전용 · 7145b9d

// @yohangel/auth-express — Better Auth en Express 5. Monta las rutas ANTES de express.json() y protege rutas con
// `requireAuth`. La sesión queda en `res.locals.session` / `res.locals.user`.
import { fromNodeHeaders, toNodeHandler } from 'better-auth/node';
import type { Express, NextFunction, Request, RequestHandler, Response } from 'express';
import { type AuthSession, type CreateAuthOptions, createAuth, getAuth } from '../auth/index.js';

export { createAuth };

/** Crea la instancia (si no existe) y monta /api/auth/* (Express 5: `*splat`). Llamar antes de `express.json()`. */
export function mountAuth(app: Express, opts: CreateAuthOptions & { basePath?: string } = {}): void {
  const { basePath = '/api/auth', ...authOpts } = opts;
  const auth = createAuth(authOpts);
  app.all(`${basePath}/*splat`, toNodeHandler(auth));
}

export type AuthLocals = { session: AuthSession['session'] | null; user: AuthSession['user'] | null };

async function load(req: Request, res: Response): Promise<AuthSession | null> {
  const s = await getAuth().api.getSession({ headers: fromNodeHeaders(req.headers) });
  res.locals.session = s?.session ?? null;
  res.locals.user = s?.user ?? null;
  return s;
}

/** 401 JSON si no hay sesión válida. */
export const requireAuth: RequestHandler = async (req: Request, res: Response, next: NextFunction) => {
  try {
    if (!(await load(req, res))) {
      res.status(401).json({ error: 'unauthorized' });
      return;
    }
    next();
  } catch (e) {
    next(e);
  }
};

/** Carga la sesión si existe, sin bloquear. */
export const optionalAuth: RequestHandler = async (req, res, next) => {
  try {
    await load(req, res);
    next();
  } catch (e) {
    next(e);
  }
};