Description
If a browser-based client connects to h's WebSocket server using the WebSocket API and later closes the connection by calling close() without any arguments, h's WebSocket server will respond with an invalid close frame with a status code of 1005 which will result in Safari and Chrome displaying an error in the console.
Client issue: hypothesis/client#1941
Steps to reproduce:
Save the following HTML file locally, open it and click the "Close connection" button.
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<span id="wsStatus">Not connected</span>
<button id="closeButton">Close connection</button>
<p>
Clicking the "Close connection" button will display an error in the
browser console in Safari and Chrome, and the WS will receive a
"close" event with a status of 1006 indicating an abnormal disconnection.
In Firefox a status of 1005 is reported.
</p>
<script>
const btn = document.querySelector('#closeButton');
const status = document.querySelector('#wsStatus');
const ws = new WebSocket('ws://localhost:5001/ws');
ws.onopen = () => status.textContent = 'Connected';
ws.onclose = e => status.textContent = `Closed (status: ${e.code})`;
btn.onclick = () => ws.close();
</script>
</body>
</html>Expected: No error message in the browser console and a close status of 1005.
Actual: Safari and Chrome show an error message in the browser console and a close status of 1006.
Notes
The 1005 status code should never be sent over the wire. Instead this code is reserved to be synthesized by the receiving end of the connection to indicate that a close frame was received with no status code.
I believe Safari and Chrome's behavior here are correct. Firefox's behavior is an error.