Dane Sabo
3299181c70
M lazy-lock.json M lua/custom/configs/lspconfig.lua M lua/custom/init.lua A lua/custom/journal.lua A nvim_venv/bin/Activate.ps1 A nvim_venv/bin/activate A nvim_venv/bin/activate.csh A nvim_venv/bin/activate.fish
103 lines
3.0 KiB
Python
103 lines
3.0 KiB
Python
"""Framer implementations.
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The implementation is responsible for encoding/decoding requests/responses.
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According to the selected type of modbus frame a prefix/suffix is added/removed
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"""
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from __future__ import annotations
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from enum import Enum
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from pymodbus.exceptions import ModbusIOException
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from pymodbus.logging import Log
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from pymodbus.pdu import DecodePDU, ModbusPDU
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class FramerType(str, Enum):
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"""Type of Modbus frame."""
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ASCII = "ascii"
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RTU = "rtu"
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SOCKET = "socket"
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TLS = "tls"
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class FramerBase:
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"""Intern base."""
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EMPTY = b''
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MIN_SIZE = 0
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def __init__(
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self,
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decoder: DecodePDU,
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) -> None:
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"""Initialize a ADU (framer) instance."""
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self.decoder = decoder
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def decode(self, _data: bytes) -> tuple[int, int, int, bytes]:
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"""Decode ADU.
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returns:
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used_len (int) or 0 to read more
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dev_id,
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tid,
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modbus request/response (bytes)
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"""
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return 0, 0, 0, self.EMPTY
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def encode(self, data: bytes, _dev_id: int, _tid: int) -> bytes:
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"""Encode ADU.
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returns:
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modbus ADU (bytes)
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"""
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return data
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def buildFrame(self, message: ModbusPDU) -> bytes:
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"""Create a ready to send modbus packet.
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:param message: The populated request/response to send
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"""
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data = message.function_code.to_bytes(1,'big') + message.encode()
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frame = self.encode(data, message.dev_id, message.transaction_id)
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return frame
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def processIncomingFrame(self, data: bytes) -> tuple[int, ModbusPDU | None]:
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"""Process new packet pattern.
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This takes in a new request packet, adds it to the current
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packet stream, and performs framing on it. That is, checks
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for complete messages, and once found, will process all that
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exist.
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"""
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used_len = 0
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while True:
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data_len, pdu = self._processIncomingFrame(data[used_len:])
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used_len += data_len
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if not data_len:
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return used_len, None
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if pdu:
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return used_len, pdu
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def _processIncomingFrame(self, data: bytes) -> tuple[int, ModbusPDU | None]:
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"""Process new packet pattern.
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This takes in a new request packet, adds it to the current
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packet stream, and performs framing on it. That is, checks
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for complete messages, and once found, will process all that
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exist.
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"""
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Log.debug("Processing: {}", data, ":hex")
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if not data:
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return 0, None
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used_len, dev_id, tid, frame_data = self.decode(data)
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if not frame_data:
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return used_len, None
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if (result := self.decoder.decode(frame_data)) is None:
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raise ModbusIOException("Unable to decode request")
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result.dev_id = dev_id
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result.transaction_id = tid
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Log.debug("Frame advanced, resetting header!!")
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return used_len, result
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