HMS MediaEngine Agent
9536e08748
- ADR-0008: Build-first, gesammelte Windows-Validierung (Auftraggeber-Freigabe) - ADR-0004 vorläufig: Rust auf GStreamer-D3D11-Elementpfad - ADR-0005 vorläufig: Nuitka Onefolder - hms_protocol: IpcServer/IpcClient mit Handshake (hello/welcome), Capabilities-Austausch, Heartbeat 500 ms bidirektional, Snapshot/Delta, Loopback-only-Enforcement, Re-Sync nach Reconnect, Version-Mismatch-Fehler - 9 Integrationstests: echter TCP-Loopback, kein Mock
73 lines
2.5 KiB
Python
73 lines
2.5 KiB
Python
"""Length-prefixed MessagePack-Framing (ADR-0003).
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4-Byte-Big-Endian-Länge, danach MessagePack-Payload. Maximale Payloadgröße
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schützt vor unkontrollierten Queues/Resourcenerschöpfung (§6.2, §33).
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"""
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from __future__ import annotations
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import asyncio
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import socket
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import struct
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import msgpack
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MAX_PAYLOAD_SIZE = 16 * 1024 * 1024 # 16 MiB Obergrenze je Nachricht
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_LENGTH = struct.Struct(">I")
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def encode_frame(payload: dict) -> bytes:
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"""Serialisiert ein dict zu length-prefixed MessagePack."""
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body = msgpack.packb(payload, use_bin_type=True)
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if len(body) > MAX_PAYLOAD_SIZE:
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raise ValueError(f"payload too large: {len(body)} > {MAX_PAYLOAD_SIZE}")
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return _LENGTH.pack(len(body)) + body
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def decode_frame(frame: bytes) -> dict:
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"""Dekodiert einen vollständigen Frame (Länge + Body)."""
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if len(frame) < _LENGTH.size:
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raise ValueError("frame too short")
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(length,) = _LENGTH.unpack_from(frame, 0)
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if length > MAX_PAYLOAD_SIZE:
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raise ValueError(f"declared length {length} exceeds limit")
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body = frame[_LENGTH.size : _LENGTH.size + length]
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if len(body) != length:
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raise ValueError(f"truncated frame: expected {length}, got {len(body)}")
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return msgpack.unpackb(body, raw=False)
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def read_frame(sock: socket.socket) -> dict:
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"""Liest einen Frame von einem verbundenen Socket."""
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header = _recv_exact(sock, _LENGTH.size)
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(length,) = _LENGTH.unpack(header)
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if length > MAX_PAYLOAD_SIZE:
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raise ValueError(f"declared length {length} exceeds limit")
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body = _recv_exact(sock, length)
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return msgpack.unpackb(body, raw=False)
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async def read_frame_async(reader: asyncio.StreamReader) -> dict:
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"""Liest einen Frame von einem asyncio-StreamReader (IPC-Server/Client)."""
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header = await reader.readexactly(_LENGTH.size)
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(length,) = _LENGTH.unpack(header)
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if length > MAX_PAYLOAD_SIZE:
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raise ValueError(f"declared length {length} exceeds limit")
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body = await reader.readexactly(length)
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return msgpack.unpackb(body, raw=False)
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def write_frame(sock: socket.socket, payload: dict) -> None:
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"""Schreibt einen Frame auf einen verbundenen Socket."""
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sock.sendall(encode_frame(payload))
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def _recv_exact(sock: socket.socket, count: int) -> bytes:
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buf = bytearray()
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while len(buf) < count:
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chunk = sock.recv(count - len(buf))
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if not chunk:
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raise ConnectionError("socket closed mid-frame")
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buf.extend(chunk)
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return bytes(buf)
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