In my case I’m trying to use plugin for vscode that requires you being signed in to an account. vscode can trigger the login window in the browser, but the callback from the browser to vscode doesn’t work because I don’t have an XDG protocol handler configured for vscode:// URLs due to the way I installed vscode (with flatpak).

Option 1: permanent fix

Register an XDG handler for the protocol: https://stackoverflow.com/a/77670791/1410035.

Option 2: one-off workaround

We can manually one-off pass the login callback to vscode without configuring anything long-term:

• trigger the login page, e.g. open vscode and click the “login” button that the plugin shows, which will open your browser
• before you login, open your browser devtools
• do the login
• look for the HTTP request that is failing with “an unknown protocol” (it’s complaining about vscode://)
• inspect the response for that request and you should see a Location header
• copy the URL value of that Location header (referred to as $THAT_URL)
• in your terminal, run

  vscode --open-url "$THAT_URL"
  

By doing this, we’ve recreated what a registered protocol handler would do.

Extra detail: as I’m using Flatpak, the auth was lost each time I closed vscode because the filesystem changes weren’t persistent. To fix that, I:

• opened vscode
• found the running “Instance” with flatpak ps
• entered the running flatpak sandbox with flatpak enter $InstanceID sh
• looked at the created directories in the home dir cd ~; ls -la
• for each of those dirs, use flatseal to make those dirs Persistent