⌘K
ENES
GitHub
phase~1 min readUpdated 2026-06-30#phase#websocket

Phase 03 · WebSocket, for Real

The migration from a homemade protocol to the real standard: the HTTP Upgrade handshake, computing Sec-WebSocket-Accept (SHA-1 + base64 + the magic GUID), the full frame format (FIN, opcode, masking, the three payload-length encodings), ping/pong/close control frames, message fragmentation, and the close handshake — verified against a real browser client.

Related notes

Low-LevelPhase 00 · OrientationWhere to start, what Atlas I and II you need first, and how this atlas is organized.Low-LevelPhase 01 · TCP from ScratchRaw BSD sockets to the bone — the handshake, Nagle, buffers, backpressure, and real network errors.Low-LevelPhase 02 · Design Your Own ProtocolFraming, binary serialization, versioning, and heartbeats over raw TCP — before adopting WebSocket.Low-LevelPhase 04 · Concurrency at ScaleLong-lived connections that need to see each other — event loops, thread pools, and the C10K→C10M problem.