fix: handle localhost and port in asWebviewUri

[jsjoeio]

This PR fixes #130151

We encountered this error in code-server (fix here: coder/code-server#3895) and noticed that resources weren't loading in webviews due to the wrong URI being returned from asWebviewUri.

I don't think Codespaces has the issue because it's always running on a standard port and so it won't have a port in the url.

Additional Context

We noticed this happening with a custom VS Code extension having issues loading resources (CSS & JS) in webviews.

I was going to try and reproduce with vscode by running yarn web but I'm not seeing the option to manually install VSIX files 🤔

[jsjoeio]

Not sure how to fix these 😅

[build/lib/layersChecker.ts]: Reference to 'URL' from 'lib.dom.d.ts' violates layer '**/vs/**/common/**' (/home/runner/work/vscode/vscode/src/vs/workbench/api/common/shared/webview.ts (60,28)
[build/lib/layersChecker.ts]: Reference to 'hostname' from 'lib.dom.d.ts' violates layer '**/vs/**/common/**' (/home/runner/work/vscode/vscode/src/vs/workbench/api/common/shared/webview.ts (61,50)
[build/lib/layersChecker.ts]: Reference to 'port' from 'lib.dom.d.ts' violates layer '**/vs/**/common/**' (/home/runner/work/vscode/vscode/src/vs/workbench/api/common/shared/webview.ts (61,106)
[build/lib/layersChecker.ts]: Reference to 'port' from 'lib.dom.d.ts' violates layer '**/vs/**/common/**' (/home/runner/work/vscode/vscode/src/vs/workbench/api/common/shared/webview.ts (61,133)

[mjbvz]

To fix the layer errors, try using our URI class instead of the built-in URL class

[jsjoeio]

I think I tried that before but the URI class doesn't have a port (though it does have it in the authority but then I'd have to split it on the :, right?) Unless I leave the port out entirely?

[Emyrk]

@mjbvz The URI puts the authority section before the vscode-resource.vscode-webview.net. So the url becomes localhost:8080.vscode-resource.vscode-webview.net which is an invalid port.

Ideally, the URI package could parse the port like URL.

[jsjoeio]

@mjbvz is this patch/fix no longer needed thanks to 649dd18?

[mjbvz]

Possibly? Although I didn't test ports specifically with that fix

Did you have a chance to test the issue from #130151?

[jsjoeio]

I spoke to @code-asher who tested it and I believe it could fix it:

> encodeAuthority("localhost:8080")
"localhost-003a8080"

> decodeAuthority("localhost-003a8080")
"localhost:8080"

> new URL("http://localhost-003a8080")
URL { href: "http://localhost-003a8080/", origin: "http://localhost-003a8080", protocol: "http:", username: "", password: "", host: "localhost-003a8080", hostname: "localhost-003a8080", port: "", pathname: "/", search: "" }

I will have to double-check and follow-up. If it does, I could instead add new tests for URLs with ports

[jsjoeio]

Closing in favor of #131447