Fetch ignoring port

🐛 Bug Report

I’m having an extremely strange issue where Fetch() completely ignores any custom port when actually running in the deployed Worker but from the quick editor, it works as expected.

I’ve gotten the Worker as simplified as much as possible to try and debug this issue. To explain the test, I have Nginx running on 443 and another application on 4567.

Steps to reproduce

addEventListener('fetch', event => {
  event.respondWith(rewriteURL(event.request))
})
 
async function rewriteURL(request) {
  let urlWithPort = new URL("https://test.file.properties:4567/download/file")
  urlWithPort.port = 9055
  //return new Response(urlWithPort) - shows the port 9055 in the URL, as it should.
  const response = await fetch(urlWithPort, request)
  return response
}

What did you expect to see?

• When I test this code from the quick editor, I get 502 (expected) because I specified port 9055 and it’s using that as I told it to
• When I test this code by visiting the deployed URL, I get an Nginx 404 page (so it’s completely ignoring port 9055)
• If you change urlWithPort.port to 4567 (or remove it), the quick editor will successfully return it from the application running on port 4567 (expect some JSON error about processing the request because the application expects some headers and parameters)

I’m expecting the deployed Worker to use the custom specified port when doing Fetch() just like it does on the quick editor.

– Wrangler wasn’t used to create this worker, so I didn’t specify any environment. I’ve entirely used the online quick editor.

[threepointone]

Let’s leave this open till we ship a fix in the runtime

[threepointone]

Whoops, reopening