SSR node middleware not working on Express

[marsidev]

What version of astro are you using?

2.9.6

Are you using an SSR adapter? If so, which one?

Node

What package manager are you using?

pnpm

What operating system are you using?

Windows

What browser are you using?

Chrome

Describe the Bug

When enabling SSR (output: "server" or output: "hybrid"), with a middleware node adapter, the middleware is not working on Express (v4.18.2) when using app.use(ssrHandler), as shown in the docs:

Instead, it works when using the middleware as follows:

app.use((req, res, next) => {
  ssrHandler(req, res, next);
});

I noticed it works as expected on Fastify (v4.21.0) with just app.use(ssrHandler).

This is my config:

export default defineConfig({
  output: "server",
  adapter: node({
    mode: "middleware",
  }),
  server: {
    port: 8000,
  },
});

This is my express server:

import express from "express";
import { handler as ssrHandler } from "./dist/server/entry.mjs";

const PORT = process.env.PORT || 8000;
const app = express();

app.use(express.static("dist/client/"));
app.use(ssrHandler); // <-- This is not working

// The following works:
// app.use((req, res, next) => {
//   ssrHandler(req, res, next);
// });

app.listen(PORT, () => {
  console.log(`Server running on http://localhost:${PORT}`);
});

I created a repo to reproduce the error:

1. Fork/clone the repo
2. Install deps (pnpm i)
3. Build the project (pnpm build)
4. Run express server (pnpm preview)
5. Go to http://localhost:8000/ssr or http://localhost:8000/api/ssr to check if works

What's the expected result?

It should work with app.use(ssrHandler).

Please fix it or at least update the docs.

Link to Minimal Reproducible Example

https://github.com/marsidev/astro-ssr-example

Participation

• I am willing to submit a pull request for this issue.

[andremralves]

It stopped working in version v5.3.0 when the locals parameter was added to the middleware function. #7385

Apparently app.use() can't handle functions with an extra parameter directly.

[yaronovsky]

When will this be addressed? It prevents me from updating node adapter

[yaronovsky]

Any news here? Not getting addresses I see

[matthewp]

Can this be fixed or should we update the docs?

[yaronovsky]

Thank you so much, it really matters