Daytona's signed preview URL targets the noVNC service root, which
serves a directory listing of the noVNC distribution rather than the
actual viewer. The result was that selecting VNC mode in the run
sandbox tab loaded an iframe of `vnc.html`, `vnc_auto.html`, … as
links instead of the desktop.
Fix it server-side by parsing the signed URL, replacing the path with
`/vnc.html`, and appending `autoconnect=true&resize=scale` so the
iframe immediately connects and scales to fit. Existing query params
on the signed URL (e.g. proxy tokens) are preserved. The intentional
url::Url use is wrapped with #[expect(disallowed_types)] since this is
internal URL manipulation, not a logging/error boundary; the
parse-failure error message omits the URL to avoid leaking creds in
client-facing API responses.
Verified live against a Daytona run on the daytona-medium snapshot:
the response now ends with /vnc.html?autoconnect=true&resize=scale
and the iframe loads the actual noVNC viewer.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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