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hms-mediaengine/packages/protocol/hms_protocol/framing.py
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HMS MediaEngine Agent 0922cc1d68 Phase 0: Repository-Initialisierung nach Bauplan v1.2
- Struktur gemäß §8 (Eigentumsgrenzen), PLAN.md als normative Basis
- Pflichtdokumente: STATUS.md, ERRORS.md, TEST_REPORT.md, CHANGELOG.md, ADRs
- ADR-0001 Python 3.13-Pin, ADR-0002 GStreamer 1.28.6-Pin (Windows),
  ADR-0003 IPC TCP+MessagePack v1
- Kernpakete: hms_protocol, hms_domain, hms_parameter, hms_artnet,
  hms_adaptive, hms_capabilities, hms_plugin_sdk
- Renderer-Spike: D3D11-Primärpfad + Dev-GL-Pfad (§36 Nr. 4-5)
- Control Core: FastAPI REST + WebSocket (§36 Nr. 9)
- Beispielplugins: Passthrough + Gaussian Blur (3 Adaptive-Quality-
  Varianten, HLSL/GLSL/GLES)
- Tools: Art-Net-Emulator, Fixture-Generator (Master32/Layer64-CSV),
  Capability-Probe
- JSON-Schemas: IPC, Plugin, Projekt, Cluster
- 121 Unit-/Integrationstests grün, Ruff grün

Gate 0 bleibt offen: Hardwaremessungen nur auf echter Windows-Referenz-
hardware gültig (§29.7, §33).
2026-09-11 00:36:59 +02:00

62 lines
2.0 KiB
Python

"""Length-prefixed MessagePack-Framing (ADR-0003).
4-Byte-Big-Endian-Länge, danach MessagePack-Payload. Maximale Payloadgröße
schützt vor unkontrollierten Queues/Resourcenerschöpfung (§6.2, §33).
"""
from __future__ import annotations
import socket
import struct
import msgpack
MAX_PAYLOAD_SIZE = 16 * 1024 * 1024 # 16 MiB Obergrenze je Nachricht
_LENGTH = struct.Struct(">I")
def encode_frame(payload: dict) -> bytes:
"""Serialisiert ein dict zu length-prefixed MessagePack."""
body = msgpack.packb(payload, use_bin_type=True)
if len(body) > MAX_PAYLOAD_SIZE:
raise ValueError(f"payload too large: {len(body)} > {MAX_PAYLOAD_SIZE}")
return _LENGTH.pack(len(body)) + body
def decode_frame(frame: bytes) -> dict:
"""Dekodiert einen vollständigen Frame (Länge + Body)."""
if len(frame) < _LENGTH.size:
raise ValueError("frame too short")
(length,) = _LENGTH.unpack_from(frame, 0)
if length > MAX_PAYLOAD_SIZE:
raise ValueError(f"declared length {length} exceeds limit")
body = frame[_LENGTH.size : _LENGTH.size + length]
if len(body) != length:
raise ValueError(f"truncated frame: expected {length}, got {len(body)}")
return msgpack.unpackb(body, raw=False)
def read_frame(sock: socket.socket) -> dict:
"""Liest einen Frame von einem verbundenen Socket."""
header = _recv_exact(sock, _LENGTH.size)
(length,) = _LENGTH.unpack(header)
if length > MAX_PAYLOAD_SIZE:
raise ValueError(f"declared length {length} exceeds limit")
body = _recv_exact(sock, length)
return msgpack.unpackb(body, raw=False)
def write_frame(sock: socket.socket, payload: dict) -> None:
"""Schreibt einen Frame auf einen verbundenen Socket."""
sock.sendall(encode_frame(payload))
def _recv_exact(sock: socket.socket, count: int) -> bytes:
buf = bytearray()
while len(buf) < count:
chunk = sock.recv(count - len(buf))
if not chunk:
raise ConnectionError("socket closed mid-frame")
buf.extend(chunk)
return bytes(buf)