Method _read_frame

unity_cli/client.py:176–223

Read framed message: 4-byte header + JSON payload. Args: sock: Connected socket. Returns: Parsed JSON payload as dictionary. Raises: ProtocolError: If header is incomplete, payload too large, or invalid JSON.

(self, sock: socket.socket)

        sock.sendall(header + payload_bytes)

    def _read_frame(self, sock: socket.socket) -> dict[str, Any]:
        """Read framed message: 4-byte header + JSON payload.

        Args:
            sock: Connected socket.

        Returns:
            Parsed JSON payload as dictionary.

        Raises:
            ProtocolError: If header is incomplete, payload too large, or invalid JSON.
        """
        sock.settimeout(self.timeout)

        header = sock.recv(HEADER_SIZE)
        if len(header) != HEADER_SIZE:
            raise ProtocolError(
                f"Expected {HEADER_SIZE}-byte header, got {len(header)} bytes",
                "PROTOCOL_ERROR",
            )

        (length,) = struct.unpack(">I", header)

        if length > MAX_PAYLOAD_BYTES:
            raise ProtocolError(
                f"Payload too large: {length} > {MAX_PAYLOAD_BYTES}",
                "PAYLOAD_TOO_LARGE",
            )

        chunks: list[bytes] = []
        remaining = length
        while remaining > 0:
            chunk_size = min(remaining, 65536)  # 64KB buffer
            chunk = sock.recv(chunk_size)
            if not chunk:
                raise ProtocolError(
                    "Connection closed while reading payload",
                    "PROTOCOL_ERROR",
                )
            chunks.append(chunk)
            remaining -= len(chunk)
        payload = b"".join(chunks)  # O(n) concatenation

        try:
            result: dict[str, Any] = json.loads(payload.decode("utf-8"))
            return result
        except json.JSONDecodeError as e:
            raise ProtocolError(f"Invalid JSON response: {e}", "MALFORMED_JSON") from e

    _RETRYABLE_CODES = frozenset({"INSTANCE_RELOADING", "INSTANCE_BUSY", "TIMEOUT", "INSTANCE_DISCONNECTED"})