briefcase run web shows blank page -- resource is blocked by OpaqueResponseBlocking??

[debboutr]

Describe the bug

I am just getting a blank web page when trying to run briefcase run web. I've found this error in devtools

and a mention in Firefox console:
A resource is blocked by OpaqueResponseBlocking, please check browser console for details. pyscript.css

Steps to reproduce

Follow the tutorial, Everything else worked fine but this is where I got held up.

Expected behavior

I was hoping to see the website as it looks in the tutorial or on the android emulator

Screenshots

No response

Environment

• Operating System: Pop!OS 22.04
• Python version: 3.10.12
• Software versions:
  • Briefcase: 0.3.20
  • Toga: 0.4.8
  • ...

Logs

Additional context

No response

[freakboy3742]

Thanks for the report.

It appears that we've been caught out by PyScript's release process. We haven't updated the web backend for a while, and we've been relying on the latest release tag. They formally deprecated the use of this tag a little over a year ago ... and at some point in the last couple of days, they removed the latest code from their CDN.

The good news is that this has already been addressed (in beeware/briefcase-web-static-template#16); the bad news is that we need to publish an update to Briefcase to make this change available (or you need to install the in-development version of Briefcase).

I was hoping to cut a new release early in the new year when I'm back in the office after a Christmas break. In the meantime, I can only apologise for the inconvenience.

[mhsmith]

Fixed by beeware/briefcase-web-static-template#16 – this will be included in the next Briefcase release.

Meanwhile you can work around this by using the development version of Briefcase:

pip install git+https://github.com/beeware/briefcase

Then re-run briefcase create web and briefcase build web.

[freakboy3742]

I've just released Briefcase 0.3.21 which should resolve this issue.