504s sending PUT requests via codespaces port forwarding

[djn24]

I'm seeing 504 errors when I make a PUT request to a server which I'm developing in the codespaces environment:

• If the amount of data in the body of the request is very small it seems to work OK.
• When it's failing, the server does get the headers of the request, but blocks trying to read the body and then times out.
• The same code works fine (with large PUTs) running locally.

I've made a small example which exhibits the problem. Here are the steps to reproduce:

1. Create a new codespace for repo https://github.com/djn24/codespaces-504.
2. Open a terminal in the codespace and type "go run server.go". You should see "Serving on :8080".
3. Click "Ports" and "Open in browser". There should be a page with "Test test test".
4. Flip back to the codespace and look at the console output from the server. It should say "PUT request received, reading body" and then nothing for 60 seconds, after which you'll see an error about unexpected EOF.
5. Go back to the browser and (assuming you're using Google Chrome) open the developer tools and select the Network tab.
6. Hit refresh on the page to send another request. You'll see the "puttest" request fail with a 504 after 60 seconds.
7. Go back to the code in the codespace, open index.html and reduce the count in the for loop down to 10 iterations. That just reduces the size of the payload in the PUT request. Go back to the browser and hit refresh again, you should see the "puttest" request complete with a 200 immediately, and the terminal in the codespace will be happy too.

You can also try cloning the git repo locally, opening it up in Visual Studio Code and running the same steps (pointing a browser at http://localhost:8080). That works fine for me with large request sizes.

[djn24]

Thought I would check back on this since it's been a while (I stopped using CodeSpaces because of the bug described above). The good news is at some point in the last three months it appears to have been fixed.