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harp-serial#

Serial transport for harp-device. Provides SerialTransport and the open_device factory, which pairs a device module or a Device class with a serial port. This is the package that pulls in pyserial.

Usage#

Like the builtin open, the returned device is connected and ready. Use it in a with block for guaranteed cleanup:

from harp import serial
from harp.device import behavior, core

# Use "COMx" on Windows, "/dev/ttyUSBx" on Linux.
with serial.open_device(behavior, port="COM3") as device:
    print(device.read(core.WhoAmI).payload)         # a core register
    print(device.read(behavior.AnalogData).payload) # a device register

Passing a device module validates the device identity on open. Pass a Device subclass instead to preserve its own type, or omit the argument entirely for schema-free access, which skips the identity check.

harp-serial is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.

harp.serial.SerialTransport #

A serial-port :class:~harp.device.client.ITransport (structural conformance).

harp.serial.open_device(device_or_module=None, *, port, baudrate=DEFAULT_BAUDRATE, raise_on_error=True) #

open_device(
    device_or_module: type[D],
    *,
    port: str,
    baudrate: int = ...,
    raise_on_error: bool = ...,
) -> D

open_device(
    device_or_module: M,
    *,
    port: str,
    baudrate: int = ...,
    raise_on_error: bool = ...,
) -> Device[M]

open_device(
    device_or_module: None = ...,
    *,
    port: str,
    baudrate: int = ...,
    raise_on_error: bool = ...,
) -> Device[None]

Build a :class:~harp.device.client.Device over a serial transport and open it.

Accepts either a device module or a :class:~harp.device.client.Device subclass:

  • Module (preferred): validates identity on open::

    from harp.device import behavior, core

    with open_device(behavior, port="COM3") as dev: dev.read(core.WhoAmI) # a core register dev.read(behavior.AnalogData) # declared by the schema

  • Device subclass: instantiates the subclass directly, preserving its type::

    with open_device(MyBehavior, port="COM3") as dev: dev.arm() # method defined on MyBehavior

Omit the first argument for schema-free access, which skips the identity check.

Like the builtin :func:open, the returned device is already connected; use it directly or in a with block for guaranteed close.