Error when using express as dev server middleware

[q1uxu]

Describe the bug

I use a express app as vite dev server middleware. When visit the website, vite dev server exit with error.

Reproduction

https://github.com/q1uxu/vite-mkcert-configureServer

steps:

1. init a vite project
2. install and use vite-plugin-mkcert
3. install express, make a simple express app, use as a vite dev server middleware

// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react-swc";
import mkcert from "vite-plugin-mkcert";
import expressApp from "./server";

// https://vite.dev/config/
export default defineConfig({
  plugins: [
    react(),
    mkcert(),
    {
      name: "vite-plugin-express",
      configureServer(server) {
        server.middlewares.use(expressApp);
      },
    },
  ],
});

// server/index.ts
import express from "express";

const app = express();

app.get("/api/ping", (req, res) => {
  res.status(200).end("ping");
});

export default app;

4. curl https://localhost:5173/

result:

var path = parseUrl$1(req).pathname || '/';
                          ^

TypeError: Cannot read properties of undefined (reading 'pathname')

System Info

Output of npx envinfo --system --npmPackages vite,vite-plugin-mkcert --binaries --browsers:

System:
  OS: Linux 5.15 Ubuntu 20.04.5 LTS (Focal Fossa)
  CPU: (8) x64 11th Gen Intel(R) Core(TM) i7-1165G7 @ 2.80GHz
  Memory: 8.21 GB / 11.36 GB
  Container: Yes
  Shell: 5.8 - /usr/bin/zsh
Binaries:
  Node: 22.12.0 - ~/.nvm/versions/node/v22.12.0/bin/node
  Yarn: 1.22.22 - ~/.nvm/versions/node/v22.12.0/bin/yarn
  npm: 10.9.0 - ~/.nvm/versions/node/v22.12.0/bin/npm
  pnpm: 9.12.2 - ~/.local/share/pnpm/pnpm
  bun: 1.1.40 - ~/.bun/bin/bun

Used package manager:

pnpm

Logs

file:///tmp/vite-project/node_modules/.pnpm/[email protected]_@[email protected]/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22512
    var path = parseUrl$1(req).pathname || '/';
                              ^

TypeError: Cannot read properties of undefined (reading 'pathname')
    at next (file:///tmp/vite-project/node_modules/.pnpm/vite@6.0.7_@types+node@22.10.5/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22512:31)
    at call (file:///tmp/vite-project/node_modules/.pnpm/vite@6.0.7_@types+node@22.10.5/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22604:3)
    at next (file:///tmp/vite-project/node_modules/.pnpm/vite@6.0.7_@types+node@22.10.5/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22539:5)
    at Function.handle (file:///tmp/vite-project/node_modules/.pnpm/vite@6.0.7_@types+node@22.10.5/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22542:3)
    at Http2SecureServer.app (file:///tmp/vite-project/node_modules/.pnpm/vite@6.0.7_@types+node@22.10.5/node_modules/vite/dist/node/chunks/dep-BJP6rrE_.js:22407:37)
    at Http2SecureServer.emit (node:events:524:28)
    at Http2SecureServer.onServerStream (node:internal/http2/compat:974:10)
    at Http2SecureServer.emit (node:events:524:28)
    at ServerHttp2Session.sessionOnStream (node:internal/http2/core:3014:19)
    at ServerHttp2Session.emit (node:events:524:28)

Node.js v22.12.0

---

[liuweiGL]

If I replace the plugin with the official vite-plugin-basic-ssl the same error occurs. So, it seems that there is an issue with the integration method of Express.