Implementation of Cli_SetDateTime, Cli_GetDateTime

[Lamelynx]

I managed to implement Cli_GetPlcDateTime, Cli_SetPlcDateTime to a PLC S7-400 in my project and want to share.
Maybe someone with more experience can implement this into python-snap7 wrapper.

def get_plc_datetime(self):
    """
    Get date and time from PLC.

    (Wrapper for function Cli_GetPlcDateTime(), this is not yet implemented in main snap7/python project)

    :return: date and time as DateTime
    """

    type_ = ctypes.c_int32
    buffer = (type_ * 9)()

    result = self.library.Cli_GetPlcDateTime(self.pointer, ctypes.byref(buffer))
    snap7.common.check_error(result, context="client")

    return datetime.datetime(
        year = buffer[5] + 1900,
        month = buffer[4] + 1,
        day = buffer[3],
        hour = buffer[2],
        minute = buffer[1],
        second = buffer[0],
        microsecond = 0
    )

def set_plc_datetime(self, dt):
    """
    Set date and time in PLC

    (Wrapper for function Cli_SetPlcDateTime(), this is not yet implemented in main snap7/python project)

    :param dt: Date and time as datetime object
    :return:
    """

    type_ = ctypes.c_int32
    buffer = (type_ * 9)()
    buffer[0] = dt.second
    buffer[1] = dt.minute
    buffer[2] = dt.hour
    buffer[3] = dt.day
    buffer[4] = dt.month - 1
    buffer[5] = dt.year - 1900

    code = self.library.Cli_SetPlcDateTime(self.pointer, ctypes.byref(buffer))
    snap7.common.check_error(code, context="client")

    return code

[gijzelaerr]

Thanks! That looks already quite good already. If you want you can try to add it to the code yourself and issue a pull request. Do you know if the emulator supports these calls? If so we can also add it to the test suite.