nBus-Client-API/nbus_hal/nbus_serial/serial_port.py

import time
import serial
from typing import Any, Callable

from beartype import beartype

from nbus_types.nbus_command_type import *
from nbus_types.nbus_exceptions.nbus_network_exception import *
from nbus_types.nbus_exceptions.nbus_node_exception import *
from nbus_hal.nbus_serial.serial_config import NBusSerialConfig
from nbus_hal.nbus_generic_port import NBusPort, NBusDelay
from nbus_types.nbus_address_type import NBusModuleAddress, NBusDeviceAddress
from nbus_hal.crc8 import crc8


def default_logger(*message: Any) -> None:
    """
    Default logger function.
    :param message: message to log
    :return: None
    """
    for i in range(len(message)):
        if isinstance(message[i], list):
            for m in message[i]:
                print(hex(m), end="|")
            continue
        print(message[i], end=" ")
    print()


@beartype
class NBusSerialPort(NBusPort):
    """
    Class representing nBus serial port.
    """
    def __init__(self, config: NBusSerialConfig):
        self._port = serial.Serial(timeout=config.timeout)
        self._port.port = config.port_name
        self._port.parity = config.parity.value
        self._port.baudrate = config.baud.value
        self._logger_cb = default_logger
        self._enable_log = config.enable_log
        self._request_attempts = config.request_attempts

    """
    ================================================================================================================
                                                API Methods
    ================================================================================================================
    """

    def open(self) -> None:
        """
        Open port.
        """
        self._port.open()
        self._port.flush()
        self._log('i', 0, 'Open communication port')

    def close(self) -> None:
        """
        Close port.
        """
        self._log('i', 0, 'Close communication port')
        self._port.close()

    def is_connected(self) -> bool:
        """
        Return connection status.
        :return: status (1 = connected, 0 = not connected)
        """
        return self._port.is_open

    def set_logger(self, callback: Callable[[Any], None]) -> None:
        """
        Set logger function.
        :param callback: logging callback
        """
        self._logger_cb = callback

    def request_broadcast(self, command: NBusCommand, data: bytearray) -> None:
        """
        Make broadcast request to nbus network.
        :param command: command id
        :param data: command data to send
        """
        request = self._create_packet([0, 0, 0, command.value], data)
        self._log("\tBRQ>", request)
        self._port.write(request)  # send message

    def request_module(self, module_addr: NBusModuleAddress, command: NBusCommand, data: bytearray,
                       long_answer: NBusDelay = 0.0) -> bytearray:
        """
        Make module request to nbus network.
        :param module_addr: address of module
        :param command: command id
        :param data: command data to send
        :param long_answer: delay in s for longer answer
        :return: | payload length | payload |
        """
        return self._request_response(module_addr, 0, command.value, data, long_answer)

    def request_device(self, module_addr: NBusModuleAddress, device_address: NBusDeviceAddress,
                       command: NBusCommand, data: bytearray, long_answer: NBusDelay = 0.0) -> bytearray:
        """
        Make device request to nbus network.
        :param module_addr: address of module
        :param device_address: address of device
        :param command: command id
        :param data: command data to send
        :param long_answer: delay in s for longer answer
        :return: | payload length | payload |
        """
        return self._request_response(module_addr, device_address, command.value, data, long_answer)

    """
    ================================================================================================================
                                                Internal Methods
    ================================================================================================================
    """

    def _request_response(self, module: int, sensor: int, command, data: bytearray,
                          long_answer: float = 0) -> bytearray:
        """
        Make request to nbus node and receive response.
        :param module: module address
        :param sensor: sensor address
        :param command: command id
        :param data: command data to send
        :param long_answer: timeout for long answer
        :return: response length | response
        """
        request = self._create_packet(bytearray([0, module, sensor, command]), data)  # create request
        self._log('d', sensor, "\tRQ>", request)  # log request

        counter = 0  # err. trials

        while True:  # try to communicate
            self._port.write(request)

            if long_answer > 0:  # wait for long answer
                time.sleep(long_answer)

            try:
                return self._receive_payload()

            except NBusErrorNetwork as Ex:  # if network error, try to reconnect
                counter += 1

                if counter > self._request_attempts:
                    raise Ex  # if out of trials, propagate exception

    def _create_packet(self, start: bytearray, data: bytearray) -> bytearray:
        """
        Create packet to send and prepare port.
        :param start: head of message
        :param data: body of message
        :return: request packet
        """
        if len(data) > 0:
            for c in data:
                start.append(c)

        if not self._port.is_open:
            self.open()
        self._port.flush()

        start[0] = len(start)
        crc_sum = crc8(start[1:])

        start.append(crc_sum)
        return start

    def _receive_payload(self) -> bytearray:
        """
        Read response from serial.
        :return: | payload len | payload
        """
        # read data length
        response_l = self._port.read(1)
        if (response_l is None) or (len(response_l) == 0):          # check if message is empty
            raise NBusErrorNetwork(NBusErrorNetworkType.EMPTY_MESSAGE)

        response_l = ord(response_l)    # convert response length to number

        # read response body
        response = self._port.read(response_l)
        if (response is None) or (len(response) != response_l):     # check for message completeness
            raise NBusErrorNetwork(NBusErrorNetworkType.MESSAGE_NOT_COMPLETE)

        # check for crc
        if response[-1] != crc8(response[:-1]):
            raise NBusErrorNetwork(NBusErrorNetworkType.DAMAGED_MESSAGE)

        self._log('d', 0, "\tRS>", [response_l] + list(response))   # log response

        # check for node error
        if response[2] & NBUS_ERR_BIT:
            raise NBusErrorNode(NBusErrorNodeType(response[3]))

        return bytearray([response_l - 4]) + bytearray(response[3:-1])   # return payload length + payload

    def _log(self, *message: Any) -> None:
        """
        Log request/response.
        :param message: message to log
        """
        if self._enable_log:
            self._logger_cb(*message)