Elysia adapter

WIP

Elysia (Bun) - Web-Fetch-native, fast cold starts. Mounts as a plugin.

Setup

import { Elysia } from 'elysia'
import { elysiaAuth } from '@gentleduck/auth/server/elysia'
import { auth } from './lib/auth'

const app = new Elysia()
  .use(elysiaAuth({ auth, prefix: '/auth' }))
  .get('/api/me', async ({ request, set }) => {
    const ctx = await auth.resolveSession(request)
    if (!ctx) {
      set.status = 401
      return { code: 'AUTH/UNAUTHENTICATED' }
    }
    return ctx.identity
  })
  .listen(3000)

The plugin mounts signin, signout, session, and providers/:providerId/begin under prefix.

Validation

Elysia ships with TypeBox; you can validate input shapes upstream of duck-auth:

import { t } from 'elysia'

app.post(
  '/auth/signin',
  ({ body }) => mountSignInHandler(body),
  {
    body: t.Object({
      providerId: t.String(),
      input: t.Record(t.String(), t.Any()),
    }),
  },
)

Malformed payloads return 400 before reaching the duck-auth runtime.

Cold-start posture

Elysia + Bun starts in <20ms. duck-auth adds a few ms (loading lazy peers, instantiating the AuthEngine). For best cold-start, avoid wiring peers you don't use - the lazy-load is per-feature.

Error handling

import { AuthError } from '@gentleduck/auth/core'

app.onError(({ code, error, set }) => {
  if (error instanceof AuthError) {
    set.status = error.status
    return error.toJSON()
  }
})