The serial port of one Partector: open, write, read a line, close. No threads.
SerialTransport
Source code in src/naneos/usb/transport.py
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77 | class SerialTransport:
# The port is USB CDC, so the baudrate is only a formality.
BAUDRATE = 9600
# How long readline() waits for a line. Also bounds how fast a reader
# thread notices that it should stop.
READ_TIMEOUT_SECONDS = 0.2
# A device streaming at 100 Hz can make open() fail transiently.
OPEN_TIMEOUT_SECONDS = 0.5
def __init__(self, port: str) -> None:
self.port = port
self._ser: serial.Serial | None = None
@property
def is_open(self) -> bool:
return self._ser is not None and self._ser.is_open
def open(self) -> None:
"""Raises ConnectionError if the port cannot be opened."""
deadline = time.monotonic() + self.OPEN_TIMEOUT_SECONDS
error: Exception | None = None
while True:
try:
self._ser = serial.Serial(
port=self.port, baudrate=self.BAUDRATE, timeout=self.READ_TIMEOUT_SECONDS
)
return
except (OSError, serial.SerialException) as e:
error = e
if time.monotonic() >= deadline:
raise ConnectionError(f"Could not open {self.port}: {error}") from error
time.sleep(0.01)
def close(self) -> None:
if self._ser is not None:
try:
self._ser.close()
except (OSError, serial.SerialException):
pass # an unplugged port cannot be closed any more than it already is
def write(self, command: str) -> None:
"""Raises ConnectionError if the port is gone."""
if self._ser is None or not self._ser.is_open:
raise ConnectionError(f"{self.port} is not open.")
try:
self._ser.write(command.encode())
except (OSError, serial.SerialException) as e:
raise ConnectionError(f"Could not write to {self.port}: {e}") from e
def readline(self) -> str:
"""One line without its line end; "" if none arrived within the timeout.
Raises ConnectionError if the port is gone.
"""
if self._ser is None or not self._ser.is_open:
raise ConnectionError(f"{self.port} is not open.")
try:
raw = self._ser.readline()
except (OSError, serial.SerialException, TypeError) as e:
# TypeError: pyserial on POSIX when the port is closed under a read.
raise ConnectionError(f"Could not read from {self.port}: {e}") from e
return raw.decode(errors="replace").replace("\r", "").replace("\n", "").replace("\x00", "")
def discard_input(self) -> None:
if self._ser is not None and self._ser.is_open:
try:
self._ser.reset_input_buffer()
except (OSError, serial.SerialException):
pass
|
open()
Raises ConnectionError if the port cannot be opened.
Source code in src/naneos/usb/transport.py
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40 | def open(self) -> None:
"""Raises ConnectionError if the port cannot be opened."""
deadline = time.monotonic() + self.OPEN_TIMEOUT_SECONDS
error: Exception | None = None
while True:
try:
self._ser = serial.Serial(
port=self.port, baudrate=self.BAUDRATE, timeout=self.READ_TIMEOUT_SECONDS
)
return
except (OSError, serial.SerialException) as e:
error = e
if time.monotonic() >= deadline:
raise ConnectionError(f"Could not open {self.port}: {error}") from error
time.sleep(0.01)
|
readline()
One line without its line end; "" if none arrived within the timeout.
Raises ConnectionError if the port is gone.
Source code in src/naneos/usb/transport.py
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70 | def readline(self) -> str:
"""One line without its line end; "" if none arrived within the timeout.
Raises ConnectionError if the port is gone.
"""
if self._ser is None or not self._ser.is_open:
raise ConnectionError(f"{self.port} is not open.")
try:
raw = self._ser.readline()
except (OSError, serial.SerialException, TypeError) as e:
# TypeError: pyserial on POSIX when the port is closed under a read.
raise ConnectionError(f"Could not read from {self.port}: {e}") from e
return raw.decode(errors="replace").replace("\r", "").replace("\n", "").replace("\x00", "")
|
write(command)
Raises ConnectionError if the port is gone.
Source code in src/naneos/usb/transport.py
| def write(self, command: str) -> None:
"""Raises ConnectionError if the port is gone."""
if self._ser is None or not self._ser.is_open:
raise ConnectionError(f"{self.port} is not open.")
try:
self._ser.write(command.encode())
except (OSError, serial.SerialException) as e:
raise ConnectionError(f"Could not write to {self.port}: {e}") from e
|