Add WebSocket listener support to NatsServer alongside the existing TCP
listener. When WebSocketOptions.Port >= 0, the server binds a second
socket, performs HTTP upgrade via WsUpgrade.TryUpgradeAsync, wraps the
connection in WsConnection for transparent frame/deframe, and hands it
to the standard NatsClient pipeline.
Changes:
- NatsClient: add IsWebSocket and WsInfo properties
- NatsServer: add RunWebSocketAcceptLoopAsync and AcceptWebSocketClientAsync,
WS listener lifecycle in StartAsync/ShutdownAsync/Dispose
- NatsOptions: change WebSocketOptions.Port default from 0 to -1 (disabled)
- WsConnection.ReadAsync: fix premature end-of-stream when ReadFrames
returns no payloads by looping until data is available
- Add WsIntegration tests (connect, ping, pub/sub over WebSocket)
- Add WsConnection masked frame and end-of-stream unit tests
- WsReadInfo: validate 64-bit frame payload length against maxPayload
before casting to int (prevents overflow/memory exhaustion)
- WsReadInfo: always send close response per RFC 6455 Section 5.5.1,
including for empty close frames
- WsUpgrade: restrict no-masking to leaf node connections only (browser
clients must always mask frames)
- CreateCloseMessage now operates on UTF-8 byte length (matching Go's
len(body) behavior) instead of character length, with proper UTF-8
boundary detection during truncation
- WsCompression.Compress now uses try/finally for exception-safe disposal
of DeflateStream and MemoryStream
Implement WsCompression with Compress/Decompress methods per RFC 7692.
Key .NET adaptation: Flush() without Dispose() on DeflateStream to produce
the correct sync flush marker that can be stripped and re-appended.
Port WsConstants from golang/nats-server/server/websocket.go lines 41-106.
Includes opcodes, frame header bits, close status codes, compression
constants, header names, path routing, and the WsClientKind enum.
Avoids re-serializing the same ServerInfo JSON on every new connection. The
cache is rebuilt when the ephemeral port is resolved. Connections that carry a
per-connection nonce (NKey auth) continue to serialize individually so the nonce
is included correctly.
Reconcile close reason tracking: feature branch's MarkClosed() and
ShouldSkipFlush/FlushAndCloseAsync now use main's ClientClosedReason
enum. ClosedState enum retained for forward compatibility.
Reject connections that send no_responders:true without headers:true,
since the 503 HMSG response requires header support. Add three tests:
connection rejection, acceptance with headers, and 503 delivery flow.
When a client sends CONNECT {"verbose":true}, the server now responds
with +OK\r\n after successfully processing CONNECT, PING, SUB, UNSUB,
and PUB/HPUB commands, matching the Go NATS server behavior.
Accumulate InMsgs/InBytes locally per ReadAsync cycle and flush once,
reducing from 4 Interlocked operations per published message to 2 per
read cycle. This matches the Go server's approach of batching stats.
When a PUB with a reply-to subject has no matching subscribers and the
sender opted into no_responders, send a 503 HMSG back on the reply
subject so request-reply callers can fail fast instead of timing out.
