## Summary
- Implements proper WebSocket subprotocol negotiation per RFC 6455 and
WHATWG standards
- Adds HeaderValueIterator utility for parsing comma-separated header
values
- Fixes WebSocket client to correctly validate server subprotocol
responses
- Sets WebSocket.protocol property to negotiated subprotocol per WHATWG
spec
- Includes comprehensive test coverage for all subprotocol scenarios
## Changes
**Core Implementation:**
- Add `HeaderValueIterator` utility for parsing comma-separated HTTP
header values
- Replace hash-based protocol matching with proper string set comparison
- Implement WHATWG compliant protocol property setting on successful
negotiation
**WebSocket Client (`WebSocketUpgradeClient.zig`):**
- Parse client subprotocols into StringSet using HeaderValueIterator
- Validate server response against requested protocols
- Set protocol property when server selects a matching subprotocol
- Allow connections when server omits Sec-WebSocket-Protocol header (per
spec)
- Reject connections when server sends unknown or empty subprotocol
values
**C++ Bindings:**
- Add `setProtocol` method to WebSocket class for updating protocol
property
- Export C binding for Zig integration
## Test Plan
Comprehensive test coverage for all subprotocol scenarios:
- ✅ Server omits Sec-WebSocket-Protocol header (connection allowed,
protocol="")
- ✅ Server sends empty Sec-WebSocket-Protocol header (connection
rejected)
- ✅ Server selects valid subprotocol from multiple client options
(protocol set correctly)
- ✅ Server responds with unknown subprotocol (connection rejected with
code 1002)
- ✅ Validates CloseEvent objects don't trigger [Circular] console bugs
All tests use proper WebSocket handshake implementation and validate
both client and server behavior per RFC 6455 requirements.
## Issues Fixed
Fixes#10459 - WebSocket client does not retrieve the protocol sent by
the server
Fixes#10672 - `obs-websocket-js` is not compatible with Bun
Fixes#17707 - Incompatibility with NodeJS when using obs-websocket-js
library
Fixes#19785 - Mismatch client protocol when connecting with multiple
Sec-WebSocket-Protocol
This enables obs-websocket-js and other libraries that rely on proper
RFC 6455 subprotocol negotiation to work correctly with Bun.
🤖 Generated with [Claude Code](https://claude.ai/code)
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
