Support servers and frameworks with the help of universal-middleware

[magne4000]

Goals

1. Widen the supported servers and frameworks list with the help of universal-middleware
2. Currently supported targets:
   • Hono
   • Express
   • Hattip
   • Webroute
   • Fastify
   • h3
   • Cloudflare
3. A unique middleware implementation supporting all above targets, and more on the way

Non-Goals

No response

Background

Auth.js middleware currently supports a few servers and frameworks, each having their own implementation, package, etc. inducing a maintenance cost.
Supporting other middleware targets is non trivial currently, time consuming and bug-prone.

Proposal

I created universal-middleware with the goal to alleviate those specific issues for library authors. You can think of it as unplugin for HTTP middlewares.

By creating a universal standard-based middleware, you can support any servers and frameworks supported by universal-middleware.

As an example is more meaningful, here is what actually look like the complete Auth.js universal handler:

import { Auth, type AuthConfig } from "@auth/core"
import type { Get, UniversalHandler } from "@universal-middleware/core"

const authjsHandler = ((config: AuthConfig) => async (request) => {
  return Auth(request, config)
}) satisfies Get<[config: AuthConfig], UniversalHandler>

export default authjsHandler

I have a working example of using this universal handler in my fork, with tests passing. The fork implementation have all the @auth/express features implemented and tested under the new frameworks-universal directory.

universal-middleware can auto-compile directly any universal middleware and handler to all its supported targets. I invite you to take a look at the documentation examples, so that you can see how easy it would be for users to use such compiled middlewares.

As an example, batijs.dev already supports Auth.js thanks to universal-middleware sub packages (such as @universal-middleware/express, @universal-middleware/hono, etc.), and is heavily tested with all servers.