v0.4.0 — connection hijack / upgrade foundation

Viltrum v0.4.0

Connection hijack foundation for custom protocols (pre-WebSocket). Cleartext HTTP/1.1 remains first-class; reverse proxy for TLS is still fine.

Engine / upgrade

• engine.Conn: read/write/close/deadlines + pushback buffer for post-message bytes
• Conn.peer_ip for upgrade/logging
• app.upgrade(method, pattern, handler) — single hijack path; HTTP loop stops for that conn
• viltrum.switching_protocols for bare 101 responses
• ServerOptions.max_conns — excess accepts get 503 + close
• read_header_timeout, send_date, server_header (opt-in; do not overwrite handler headers)
• http.http_date / viltrum.http_date for IMF-fixdate
• TE + Content-Length conflict → 400

Docs & example

• docs/upgrade.md — leftover ownership, shutdown behaviour
• docs/connection.md, docs/deploy.md, docs/request-response.md, ROADMAP.md
• examples/upgrade_echo

Tests

• v test http/ · router/ · engine/ (TCP integration + Conn pushback unit tests)
• CI builds upgrade_echo

From 0.3.x polish (included)

• Chunked/TE reject; Expect 100-continue; HEAD body omit + GET fallback
• Absolute-form target, OPTIONS *; patch / options / head
• App.server_options (renamed from options for ServerOptions)

Next

v0.5 — WebSocket (ws://) on this upgrade path. Interest: interest:websocket Collect WebSocket (ws://) use-cases; no implementation in 0.3.x

Full notes: CHANGELOG.md · ROADMAP.md