scott
a6a0f1b246
Starting point for Windows packaging. Serial backend will be replaced with pyserial; PyInstaller used to produce a standalone .exe. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
127 lines
4.6 KiB
Python
127 lines
4.6 KiB
Python
"""
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serial_port.py — Minimal 8N1 serial port using only the Python standard library.
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Replaces pyserial for TrueNAS environments where pip is unavailable.
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"""
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import fcntl
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import os
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import select
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import termios
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import time
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from typing import Optional
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class SerialPort:
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BAUD_MAP = {
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9600: termios.B9600,
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19200: termios.B19200,
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38400: termios.B38400,
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57600: termios.B57600,
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115200: termios.B115200,
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}
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def __init__(self, port: str, baudrate: int = 115200, timeout: float = 5.0):
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self.port = port
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self.baudrate = baudrate
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self.timeout = timeout
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self._fd: Optional[int] = None
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self._saved_attrs = None
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# ── Open / close ──────────────────────────────────────────────────────────
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def open(self):
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try:
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self._fd = os.open(self.port, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK)
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except OSError as e:
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raise OSError(f"Cannot open {self.port}: {e}") from e
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# Switch back to blocking mode now that O_NOCTTY is set
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flags = fcntl.fcntl(self._fd, fcntl.F_GETFL)
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fcntl.fcntl(self._fd, fcntl.F_SETFL, flags & ~os.O_NONBLOCK)
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self._saved_attrs = termios.tcgetattr(self._fd)
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# Raw 8N1: iflag, oflag, cflag, lflag, ispeed, ospeed, cc
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attrs = list(termios.tcgetattr(self._fd))
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baud = self.BAUD_MAP.get(self.baudrate, termios.B115200)
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attrs[0] = termios.IGNBRK # iflag
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attrs[1] = 0 # oflag
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attrs[2] = termios.CS8 | termios.CREAD | termios.CLOCAL # cflag
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attrs[3] = 0 # lflag (raw)
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attrs[4] = baud # ispeed
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attrs[5] = baud # ospeed
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attrs[6][termios.VMIN] = 0
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attrs[6][termios.VTIME] = min(int(self.timeout * 10), 255)
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termios.tcsetattr(self._fd, termios.TCSANOW, attrs)
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termios.tcflush(self._fd, termios.TCIOFLUSH)
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def close(self):
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if self._fd is not None:
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try:
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if self._saved_attrs:
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termios.tcsetattr(self._fd, termios.TCSADRAIN, self._saved_attrs)
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os.close(self._fd)
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except OSError:
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pass
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finally:
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self._fd = None
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@property
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def is_open(self) -> bool:
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return self._fd is not None
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# ── Read / write ──────────────────────────────────────────────────────────
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def write(self, data: bytes):
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if self._fd is None:
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raise OSError("Port is not open")
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os.write(self._fd, data)
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def read_chunk(self, size: int = 4096) -> bytes:
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if self._fd is None:
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raise OSError("Port is not open")
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try:
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return os.read(self._fd, size)
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except OSError:
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return b""
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def read_until_quiet(self, quiet_period: float = 0.5,
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timeout: Optional[float] = None) -> str:
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"""
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Read until no new bytes arrive for `quiet_period` seconds,
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or until `timeout` (default: self.timeout) seconds have elapsed.
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Pass a longer timeout for operations like curl that take more time.
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"""
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output = b""
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deadline = time.monotonic() + (timeout if timeout is not None else self.timeout)
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last_rx = time.monotonic()
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while True:
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now = time.monotonic()
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if now >= deadline:
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break
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if output and (now - last_rx) >= quiet_period:
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break
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wait = min(deadline - now, quiet_period)
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ready, _, _ = select.select([self._fd], [], [], wait)
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if ready:
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chunk = self.read_chunk()
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if chunk:
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output += chunk
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last_rx = time.monotonic()
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return output.decode("utf-8", errors="replace")
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def send_line(self, cmd: str = "", delay: float = 0.3):
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self.write((cmd + "\r\n").encode("utf-8"))
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time.sleep(delay)
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# ── Context manager ───────────────────────────────────────────────────────
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def __enter__(self):
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self.open()
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return self
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def __exit__(self, *_):
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self.close()
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