325 lines
12 KiB
Python
325 lines
12 KiB
Python
"""Base for all clients."""
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from __future__ import annotations
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import asyncio
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import socket
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from dataclasses import dataclass
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from typing import Any, Callable
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from pymodbus.client.mixin import ModbusClientMixin
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from pymodbus.exceptions import ConnectionException, ModbusIOException
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from pymodbus.factory import ClientDecoder
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from pymodbus.framer import ModbusFramer
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from pymodbus.logging import Log
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from pymodbus.pdu import ModbusRequest, ModbusResponse
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from pymodbus.transaction import DictTransactionManager
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from pymodbus.transport import CommParams, ModbusProtocol
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from pymodbus.utilities import ModbusTransactionState
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class ModbusBaseClient(ModbusClientMixin, ModbusProtocol):
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"""**ModbusBaseClient**
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**Parameters common to all clients**:
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:param framer: (optional) Modbus Framer class.
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:param timeout: (optional) Timeout for a request, in seconds.
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:param retries: (optional) Max number of retries per request.
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:param retry_on_empty: (optional) Retry on empty response.
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:param close_comm_on_error: (optional) Close connection on error.
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:param strict: (optional) Strict timing, 1.5 character between requests.
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:param broadcast_enable: (optional) True to treat id 0 as broadcast address.
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:param reconnect_delay: (optional) Minimum delay in milliseconds before reconnecting.
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:param reconnect_delay_max: (optional) Maximum delay in milliseconds before reconnecting.
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:param on_reconnect_callback: (optional) Function that will be called just before a reconnection attempt.
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:param no_resend_on_retry: (optional) Do not resend request when retrying due to missing response.
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:param kwargs: (optional) Experimental parameters.
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.. tip::
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Common parameters and all external methods for all clients are documented here,
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and not repeated with each client.
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.. tip::
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**reconnect_delay** doubles automatically with each unsuccessful connect, from
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**reconnect_delay** to **reconnect_delay_max**.
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Set `reconnect_delay=0` to avoid automatic reconnection.
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:mod:`ModbusBaseClient` is normally not referenced outside :mod:`pymodbus`.
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**Application methods, common to all clients**:
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"""
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@dataclass
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class _params:
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"""Parameter class."""
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retries: int = None
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retry_on_empty: bool = None
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close_comm_on_error: bool = None
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strict: bool = None
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broadcast_enable: bool = None
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reconnect_delay: int = None
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source_address: tuple[str, int] = None
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server_hostname: str = None
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def __init__( # pylint: disable=too-many-arguments
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self,
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framer: type[ModbusFramer] = None,
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timeout: float = 3,
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retries: int = 3,
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retry_on_empty: bool = False,
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close_comm_on_error: bool = False,
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strict: bool = True,
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broadcast_enable: bool = False,
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reconnect_delay: float = 0.1,
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reconnect_delay_max: float = 300,
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on_reconnect_callback: Callable[[], None] | None = None,
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no_resend_on_retry: bool = False,
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**kwargs: Any,
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) -> None:
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"""Initialize a client instance."""
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ModbusClientMixin.__init__(self)
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self.use_sync = kwargs.get("use_sync", False)
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setup_params = CommParams(
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comm_type=kwargs.get("CommType"),
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comm_name="comm",
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source_address=kwargs.get("source_address", ("0.0.0.0", 0)),
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reconnect_delay=reconnect_delay,
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reconnect_delay_max=reconnect_delay_max,
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timeout_connect=timeout,
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host=kwargs.get("host", None),
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port=kwargs.get("port", 0),
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sslctx=kwargs.get("sslctx", None),
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baudrate=kwargs.get("baudrate", None),
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bytesize=kwargs.get("bytesize", None),
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parity=kwargs.get("parity", None),
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stopbits=kwargs.get("stopbits", None),
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handle_local_echo=kwargs.get("handle_local_echo", False),
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)
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if not self.use_sync:
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ModbusProtocol.__init__(
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self,
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setup_params,
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False,
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)
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else:
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self.comm_params = setup_params
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self.params = self._params()
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self.params.retries = int(retries)
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self.params.retry_on_empty = bool(retry_on_empty)
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self.params.close_comm_on_error = bool(close_comm_on_error)
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self.params.strict = bool(strict)
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self.params.broadcast_enable = bool(broadcast_enable)
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self.on_reconnect_callback = on_reconnect_callback
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self.retry_on_empty: int = 0
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self.no_resend_on_retry = no_resend_on_retry
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self.slaves: list[int] = []
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# Common variables.
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self.framer = framer(ClientDecoder(), self)
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self.transaction = DictTransactionManager(
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self, retries=retries, retry_on_empty=retry_on_empty, **kwargs
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)
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self.reconnect_delay_current = self.params.reconnect_delay
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self.use_udp = False
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self.state = ModbusTransactionState.IDLE
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self.last_frame_end: float = 0
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self.silent_interval: float = 0
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# ----------------------------------------------------------------------- #
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# Client external interface
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# ----------------------------------------------------------------------- #
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@property
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def connected(self):
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"""Connect internal."""
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return True
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def register(self, custom_response_class: ModbusResponse) -> None:
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"""Register a custom response class with the decoder (call **sync**).
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:param custom_response_class: (optional) Modbus response class.
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:raises MessageRegisterException: Check exception text.
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Use register() to add non-standard responses (like e.g. a login prompt) and
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have them interpreted automatically.
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"""
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self.framer.decoder.register(custom_response_class)
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def close(self, reconnect=False) -> None:
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"""Close connection."""
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if reconnect:
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self.connection_lost(asyncio.TimeoutError("Server not responding"))
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else:
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self.transport_close()
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def idle_time(self) -> float:
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"""Time before initiating next transaction (call **sync**).
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Applications can call message functions without checking idle_time(),
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this is done automatically.
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"""
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if self.last_frame_end is None or self.silent_interval is None:
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return 0
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return self.last_frame_end + self.silent_interval
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def execute(self, request: ModbusRequest = None) -> ModbusResponse:
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"""Execute request and get response (call **sync/async**).
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:param request: The request to process
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:returns: The result of the request execution
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:raises ConnectionException: Check exception text.
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"""
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if self.use_sync:
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if not self.connect():
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raise ConnectionException(f"Failed to connect[{self!s}]")
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return self.transaction.execute(request)
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if not self.transport:
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raise ConnectionException(f"Not connected[{self!s}]")
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return self.async_execute(request)
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# ----------------------------------------------------------------------- #
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# Merged client methods
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# ----------------------------------------------------------------------- #
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async def async_execute(self, request=None):
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"""Execute requests asynchronously."""
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request.transaction_id = self.transaction.getNextTID()
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packet = self.framer.buildPacket(request)
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count = 0
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while count <= self.params.retries:
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if not count or not self.no_resend_on_retry:
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self.transport_send(packet)
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if self.params.broadcast_enable and not request.slave_id:
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resp = b"Broadcast write sent - no response expected"
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break
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try:
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req = self._build_response(request.transaction_id)
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resp = await asyncio.wait_for(
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req, timeout=self.comm_params.timeout_connect
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)
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break
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except asyncio.exceptions.TimeoutError:
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count += 1
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if count > self.params.retries:
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self.close(reconnect=True)
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raise ModbusIOException(
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f"ERROR: No response received after {self.params.retries} retries"
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)
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return resp
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def callback_data(self, data: bytes, addr: tuple = None) -> int:
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"""Handle received data
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returns number of bytes consumed
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"""
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self.framer.processIncomingPacket(data, self._handle_response, slave=0)
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return len(data)
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def callback_disconnected(self, _reason: Exception) -> None:
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"""Handle lost connection"""
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for tid in list(self.transaction):
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self.raise_future(
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self.transaction.getTransaction(tid),
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ConnectionException("Connection lost during request"),
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)
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async def connect(self):
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"""Connect to the modbus remote host."""
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def raise_future(self, my_future, exc):
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"""Set exception of a future if not done."""
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if not my_future.done():
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my_future.set_exception(exc)
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def _handle_response(self, reply, **_kwargs):
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"""Handle the processed response and link to correct deferred."""
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if reply is not None:
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tid = reply.transaction_id
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if handler := self.transaction.getTransaction(tid):
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if not handler.done():
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handler.set_result(reply)
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else:
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Log.debug("Unrequested message: {}", reply, ":str")
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def _build_response(self, tid):
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"""Return a deferred response for the current request."""
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my_future = asyncio.Future()
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if not self.transport:
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self.raise_future(my_future, ConnectionException("Client is not connected"))
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else:
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self.transaction.addTransaction(my_future, tid)
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return my_future
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# ----------------------------------------------------------------------- #
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# Internal methods
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# ----------------------------------------------------------------------- #
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def send(self, request):
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"""Send request.
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:meta private:
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"""
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if self.state != ModbusTransactionState.RETRYING:
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Log.debug('New Transaction state "SENDING"')
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self.state = ModbusTransactionState.SENDING
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return request
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def recv(self, size):
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"""Receive data.
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:meta private:
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"""
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return size
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@classmethod
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def _get_address_family(cls, address):
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"""Get the correct address family."""
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try:
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_ = socket.inet_pton(socket.AF_INET6, address)
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except OSError: # not a valid ipv6 address
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return socket.AF_INET
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return socket.AF_INET6
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# ----------------------------------------------------------------------- #
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# The magic methods
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# ----------------------------------------------------------------------- #
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def __enter__(self):
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"""Implement the client with enter block.
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:returns: The current instance of the client
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:raises ConnectionException:
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"""
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if not self.connect():
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raise ConnectionException(f"Failed to connect[{self.__str__()}]")
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return self
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async def __aenter__(self):
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"""Implement the client with enter block.
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:returns: The current instance of the client
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:raises ConnectionException:
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"""
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if not await self.connect():
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raise ConnectionException(f"Failed to connect[{self.__str__()}]")
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return self
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def __exit__(self, klass, value, traceback):
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"""Implement the client with exit block."""
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self.close()
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async def __aexit__(self, klass, value, traceback):
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"""Implement the client with exit block."""
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self.close()
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def __str__(self):
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"""Build a string representation of the connection.
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:returns: The string representation
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"""
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return (
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f"{self.__class__.__name__} {self.comm_params.host}:{self.comm_params.port}"
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)
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