Socket.IO transport upgrade does not work with Next.js 13.2.5-canary.26

[FFdhorkin]

Link to the code that reproduces this issue or a replay of the bug

https://codesandbox.io/p/sandbox/nextjs-socketio-forked-39xjkv?file=/app/page.jsx:1,1

To Reproduce

1. Open the above code sandbox
2. open dev tools
3. you will see a console message like Connected 3JVo-y0FEk3lIPAkAAAP with polling
4. network tools shows a ton of /api/my_awesome_socket/?EIO=4&transport=polling calls

Current vs. Expected behavior

After the Connected 3JVo-y0FEk3lIPAkAAAP with polling message, eventually there should be a Upgraded from polling to websocket message, but this never happens even though the expected 101 Switching Protocols shows in the network tab.

Instead, it just stays at http polling transport, with additional calls going out.

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
      Platform: linux
      Arch: x64
      Version: #1 SMP Fri Jan 27 02:56:13 UTC 2023
    Binaries:
      Node: 18.16.1
      npm: 9.5.1
      Yarn: 3.6.1
      pnpm: 8.5.1
    Relevant Packages:
      next: 13.4.20-canary.26
      eslint-config-next: N/A
      react: 18.2.0
      react-dom: 18.2.0
      typescript: 5.1.6
    Next.js Config:
      output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Additional context

The fix for #49334 introduced this issue.

Might be worth looking at this part of Socket.io's docs: https://socket.io/docs/v4/troubleshooting-connection-issues/#problem-the-socket-is-stuck-in-http-long-polling

We might also need the changes that were in this abandoned PR: #54502

[danieljee]

I'm having the same issue running version 13.4.13
Relevant apteryxxyz/next-ws#6

[captain-derp]

This is also happening with next.js 13.5.3 when using custom server with socket.io

[Pengap]

I had the same problem with the upgrade, but I happened to see this comment #54961 (comment).
It seems to be related to using undici, I ended up downgrading to 13.4.12 and everything worked fine.

[Pengap]

When you upgrade and find that you can't use sockets and are using middleware, try to exclude the 'websokcet path' from the matcher

[github-actions]

This closed issue has been automatically locked because it had no new activity for 2 weeks. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.