Allow use of builtin Node WebSocket when available

[sbc100]

Node v21 and up have native WebSocket support. This change makes the import of the external ws module conditional so it will only run on older versions of node.

See #26676

[sbc100]

@jeroen

[jeroen]

Actually Claude suggests we also need to update the event handlers, see the second half of changes in libsockfs.js here: https://github.com/jeroen/emscripten/pull/1/changes

Because peer.socket.on('open', handleOpen) only applies to the ws implementation we no longer condition that on if (ENVIRONMENT_IS_NODE) but instead on if (typeof peer.socket.on === 'function') .

[sbc100]

Actually Claude suggests we also need to update the event handlers, see the second half of changes in libsockfs.js here: https://github.com/jeroen/emscripten/pull/1/changes

Because peer.socket.on('open', handleOpen) only applies to the ws implementation we no longer condition that on if (ENVIRONMENT_IS_NODE) but instead on if (typeof peer.socket.on === 'function') .

Good point. I decided to cleanup that code a bit first: #26683

[sbc100]

Done. PTAL

[sbc100]

Looks like we cannot switch just yet because node is sending the subprocols headers in the format of foo, bar but websockify doesn't handle the space after the comma just yet. See novnc/websockify#632

[jeroen]

@sbc100 should we maybe fix this in nodejs to behave the same as in browsers? There are many different websockify implementations and it may take a long time for this fix to end up on server distributions.

[sbc100]

Are you suggesting an upstream node fix or some kind of monkey patching at runtime?

Also, are you sure of the browser behavour? I didn't confirm yet