gateway_plc/gateway/snap7_client.py

import snap7
import logging
from threading import Lock
import time
from snap7.util import *

class Snap7Client:
    """Snap7客户端，处理与PLC的通信"""

    def __init__(self, ip, rack, slot, reader_threads, max_retries=5, retry_base_delay=1):
        """
        初始化Snap7客户端

        Args:
            ip: PLC IP地址
            rack: Rack编号
            slot: Slot编号
            max_retries: 最大重试次数
            retry_base_delay: 基础重试延迟（秒）
        """
        self.ip = ip
        self.rack = rack
        self.slot = slot
        self.client = snap7.client.Client()
        self.lock = Lock()
        self.connected = False
        self.max_retries = max_retries
        self.retry_base_delay = retry_base_delay
        self.last_connect_attempt = 0
        self.retry_count = 0
        self.reader_threads = reader_threads
        self.logger = logging.getLogger(f"Snap7Client[{ip}]")

    def is_valid_connection(self):
        """检查连接是否真正有效"""
        try:
            # 尝试读取PLC的运行状态
            cpu_state = self.client.get_cpu_state()
            print("当前 CPU 状态:", cpu_state)
            return cpu_state in ['S7CpuStatusRun', 'S7CpuStatusStop']
        except:
            return False

    def connect(self):
        """建立与PLC的连接并验证"""
        current_time = time.time()
        # 指数退避重试
        if self.retry_count > 0:
            delay = min(self.retry_base_delay * (2 ** (self.retry_count - 1)), 30)
            if current_time - self.last_connect_attempt < delay:
                return False  # 未到重试时间

        self.last_connect_attempt = current_time
        try:
            with self.lock:   # 进入锁，其他线程需等待
                self.client.connect(self.ip, self.rack, self.slot)

                # 验证连接是否真正有效
                if self.client.get_connected() and self.is_valid_connection():
                    self.connected = True
                    self.retry_count = 0  # 重置重试计数
                    self.logger.info(f"Successfully connected to PLC {self.ip}")
                    return True
                else:
                    self.connected = False
                    self.logger.warning(f"Connection to {self.ip} established but PLC is not responding")
                    try:
                        self.client.disconnect()
                    except:
                        pass
                    return False
        except Exception as e:
            self.retry_count = min(self.retry_count + 1, self.max_retries)
            self.logger.error(f"Connection to {self.ip} failed (attempt {self.retry_count}/{self.max_retries}): {e}")
            self.connected = False
            return False

    def read_db(self, db_number, offset, size):
        """
        从DB块读取数据

        Args:
            db_number: DB编号
            offset: 起始偏移量
            size: 读取字节数

        Returns:
            bytearray: 读取的数据，如果失败返回None
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Read failed: not connected to {self.ip}")
            return None  # 返回None而不是零填充数据

        try:
            with self.lock:   # 进入锁，其他线程需等待
                data = self.client.db_read(db_number, offset, size)
                # 验证返回数据的有效性
                if data is None or len(data) != size:
                    self.connected = False
                    self.logger.error(f"Read DB{db_number} returned invalid data size (expected {size}, got {len(data) if data else 0})")
                    return None
                return data
        except Exception as e:
            self.logger.error(f"Read DB{db_number} error: {e}")
            self.connected = False
            return None

    def read_db_bool(self, db_number, offset, bit_length):
        """
        从 DB 块中读取一个字节，并提取其中的多个 BOOL 位

        Args:
            db_number (int): DB块编号
            offset (int): 要读取的字节偏移地址
            bit_length: 第几位，如1，表示第1位

        Returns:
            result:返回位值
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Read failed: not connected to {self.ip}")
            return None  # 返回None而不是零填充数据

        try:
            with self.lock:
                data = self.client.db_read(db_number, offset, 1)
                result = {}

                for bit in range(bit_length):
                    result[bit] = bool(data[0] & (1 << bit))

                if result is None or len(result) != bit_length:
                    self.connected = False
                    self.logger.error(f"Read DB{db_number} returned invalid data size (expected {bit_length}, got {len(result) if data else 0})")
                    return None
                return result
        except Exception as e:
            self.logger.error(f"Read DB{db_number} error: {e}")
            self.connected = False
            return None

    def write_db(self, db_number, offset, data):
        """
        向DB块写入数据

        Args:
            db_number: DB编号
            offset: 起始偏移量
            data: 要写入的数据

        Returns:
            bool: 是否写入成功
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Write failed: not connected to {self.ip}")
            return False

        try:
            with self.lock:
                self.client.db_write(db_number, offset, data)
                self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
                return True
        except Exception as e:
            self.logger.error(f"Write DB{db_number} error: {e}")
            self.connected = False
            return False

    def batch_write_db(self, db_number, offset, data):
        """
        向DB块写入数据

        Args:
            db_number: DB编号
            offset: 起始偏移量
            data: 要写入的数据

        Returns:
            bool: 是否写入成功
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Write failed: not connected to {self.ip}")
            return False

        try:
            with self.lock:
                self.client.db_write(db_number, offset, data)
                self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
                return True
        except Exception as e:
            self.logger.error(f"Write DB{db_number} error: {e}")
            self.connected = False
            return False

    def write_db_bool(self, db_number, offset, data):
        """
        向DB块写入数据

        Args:
            db_number: DB编号
            offset: 起始偏移量
            data: 要写入的bool类型数据

        Returns:
            bool: 是否写入成功
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Write failed: not connected to {self.ip}")
            return False

        try:
            with self.lock:
                self.client.db_write(db_number, offset, data)
                self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
                return True
        except Exception as e:
            self.logger.error(f"Write DB{db_number} error: {e}")
            self.connected = False
            return False

    def batch_write_db_bool(self, db_number, offset, data):
        """
        向DB块写入数据

        Args:
            db_number: DB编号
            offset: 起始偏移量
            data: 要写入的bool类型数据

        Returns:
            bool: 是否写入成功
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Write failed: not connected to {self.ip}")
            return False

        try:
            with self.lock:
                print(db_number, offset, data)
                self.client.db_write(db_number, offset, data)
                self.logger.debug(f"Wrote {len(data)} bytes to DB{db_number} offset {offset}")
                return True
        except Exception as e:
            self.logger.error(f"Write DB{db_number} error: {e}")
            self.connected = False
            return False

    def write_generic(self, db_number, offset, data_type, value):
        """
        通用写入接口，支持多种数据类型
        Args:
            db_number: DB块编号
            offset: 起始偏移量（字节或位，对于bool类型）
            data_type: 数据类型 ('bool', 'byte', 'int', 'word', 'real', 'dint', 'dword')
            value: 要写入的值（可以是单个值或列表）
        Returns:
            bool: 是否写入成功
        """
        if not self.connected and not self.connect():
            self.logger.warning(f"Write failed: not connected to {self.ip}")
            return False

        try:
            if data_type == 'bool':
                # 对于bool，offset是位偏移
                byte_offset = offset // 8
                bit_offset = offset % 8

                # 读取当前字节
                current_byte = self.read_db(db_number, byte_offset, 1)
                if current_byte is None:
                    return False

                # 修改特定位
                if isinstance(value, list):
                    # 多个bool值
                    for i, val in enumerate(value):
                        current_bit = bit_offset + i
                        byte_idx = current_bit // 8
                        bit_idx = current_bit % 8

                        if val:
                            current_byte[0] |= (1 << bit_idx)
                        else:
                            current_byte[0] &= ~(1 << bit_idx)
                else:
                    # 单个bool值
                    if value:
                        current_byte[0] |= (1 << bit_offset)
                    else:
                        current_byte[0] &= ~(1 << bit_offset)

                # 写回修改后的字节
                return self.write_db_bool(db_number, byte_offset, current_byte)

            elif data_type == 'byte':
                if isinstance(value, list):
                    # 批量写入
                    for i, val in enumerate(value):
                        if val < 0 or val > 255:
                            self.logger.error(f"Byte value out of range: {val}")
                            return False
                        if not self.write_db(db_number, offset + i, bytes([val])):
                            return False
                    return True
                else:
                    # 单个字节
                    if value < 0 or value > 255:
                        self.logger.error(f"Byte value out of range: {value}")
                        return False
                    return self.write_db(db_number, offset, bytes([value]))

            elif data_type in ['int', 'word']:
                if not isinstance(value, list):
                    value = [value]

                for i, val in enumerate(value):
                    # 确保int值在范围内
                    if data_type == 'int' and (val < -32768 or val > 32767):
                        self.logger.error(f"Int value out of range: {val}")
                        return False
                    elif data_type == 'word' and (val < 0 or val > 65535):
                        self.logger.error(f"Word value out of range: {val}")
                        return False

                    data = bytearray(2)
                    if data_type == 'int':
                        set_int(data, 0, val)
                    else:
                        set_word(data, 0, val)

                    if not self.write_db(db_number, offset + i * 2, data):
                        return False
                return True

            elif data_type in ['dint', 'dword', 'real']:
                if not isinstance(value, list):
                    value = [value]

                for i, val in enumerate(value):
                    data = bytearray(4)
                    if data_type == 'dint':
                        if val < -2147483648 or val > 2147483647:
                            self.logger.error(f"DInt value out of range: {val}")
                            return False
                        set_dint(data, 0, val)
                    elif data_type == 'dword':
                        if val < 0 or val > 4294967295:
                            self.logger.error(f"DWord value out of range: {val}")
                            return False
                        set_dword(data, 0, val)
                    else:  # real
                        set_real(data, 0, float(val))

                    if not self.write_db(db_number, offset + i * 4, data):
                        return False
                return True

            else:
                self.logger.error(f"Unsupported data type: {data_type}")
                return False

        except Exception as e:
            self.logger.error(f"Error writing {data_type} to DB{db_number} offset {offset}: {e}")
            return False

    # -----------------
    # 新增
    # -----------------
    def cache_large_data_block(self, db_number, offset, size=6000):
        """
        一次性读取指定大小的数据并缓存
        参数:
            db_number: DB块编号
            start_offset: 起始偏移量
            size: 要读取的字节数，默认6000
        返回值:
            成功返回True，失败返回False
        """
        try:
            self.data_cache = self.read_db(db_number, offset, size)
            if self.data_cache is not None:
                self.cache_db_number = db_number
                self.cache_offset = offset
                self.logger.info(f"Successfully cached {size} bytes from DB{db_number} starting at offset {offset}")
                return True
            else:
                self.logger.error(f"Failed to cache {size} bytes from DB{db_number} starting at offset {offset}")
                return False
        except Exception as e:
            self.logger.error(f"Error caching data: {e}")
            return False

    def read_db_from_memory_cache(self, db_number, offset, required_size, array_name, reader_threads):
        """
        通用内存数组读取：从PLCDataReaderThread实例的内存数组中，提取DB块的目标字节片段
        参数说明：
            - 已删除无用的 cache_file 参数（原文件缓存逻辑已替换为内存数组）
        返回值:
            bytearray | None: 所需的字节片段，失败返回None
        """
        try:
            # -------------------------- 关键修改1：正确遍历元组并匹配线程 --------------------------
            target_thread = None
            # 遍历 reader_threads：每个元素是 (area_name_str, PLCDataReaderThread实例) 的元组
            for area_name_str, thread_instance in reader_threads:
                # 匹配条件：线程实例的 custom_array_name == 传入的 array_name（数组名在_thread实例上）
                if thread_instance.custom_array_name == array_name:
                    target_thread = thread_instance  # 拿到真正的线程实例
                    break

            # -------------------------- 关键修改2：校验线程实例是否找到 --------------------------
            if target_thread is None:
                # 若未找到，打印所有已存在的线程数组名，便于调试
                existing_arrays = [t.custom_array_name for _, t in reader_threads]
                self.logger.error(
                    f"❌ 未找到数组{array_name}对应的线程实例！"
                    f"已存在的数组名：{existing_arrays}，请检查数组名是否拼写正确"
                )
                return None

            # -------------------------- 后续逻辑不变（但需确认线程实例有效） --------------------------
            # 校验线程实例上是否存在数组（array_name 就是线程的 custom_array_name）
            if not hasattr(target_thread, array_name):
                self.logger.error(f"❌ 线程实例{target_thread.name}上不存在数组{array_name}（线程初始化失败）")
                return None

            # 线程安全获取数组数据（调用线程自带方法，内部已加锁）
            custom_array = target_thread.get_custom_array()
            if not custom_array:
                self.logger.warning(f"⚠️ 数组{array_name}为空，无可用数据")
                return None

            if not isinstance(custom_array[0], bytearray):
                self.logger.error(
                    f"❌ 数组{array_name}的元素类型错误："
                    f"期望bytearray，实际{type(custom_array).__name__}"
                )
                return None

            # 验证数据长度是否满足需求
            total_byte_len = len(custom_array[0])
            if total_byte_len < offset + required_size:
                self.logger.warning(
                    f"⚠️ DB{db_number}内存数据不完整："
                    f"数组{array_name}最新数据共{total_byte_len}字节，"
                    f"需从偏移{offset}读取{required_size}字节（需{offset + required_size}字节）"
                )
                available_size = total_byte_len - offset
                if available_size <= 0:
                    self.logger.error(f"❌ 偏移{offset}超出数据范围（最大偏移：{total_byte_len - 1}）")
                    return None
                required_size = available_size

            return custom_array[0]

        except Exception as e:
            self.logger.error(f"🔴 读取内存数组{array_name}异常：{str(e)}", exc_info=True)
            return None

    def read_generic(self, db_number, offset, data_type, array_name, count=1):
        """
        通用读取接口（改进）：
        - DB100：优先从缓存文件读取 → 再内存缓存 → 最后PLC
        - 其他DB块：保持原逻辑（内存缓存→PLC）
        """
        # 1、处理DB数据块：优先从缓存文件读取
        raw_data = None
        if raw_data is None:
            array_name = array_name
            raw_data = self.read_db_from_memory_cache(db_number, offset, count, array_name, self.reader_threads)
            if raw_data is not None:
                print(f"从内存数组中读取DB{db_number}的数据")
                self.logger.debug(f"从内存数组中读取DB{db_number}（数组：{array_name}）")

                try:
                    if data_type == 'bool':
                        # 对于bool，offset是位偏移
                        start_byte = offset // 8
                        start_bit_in_byte = offset % 8

                        # 计算需要读取的字节数
                        end_bit = offset + count - 1
                        end_byte = end_bit // 8
                        # 检查数据长度是否足够

                        result = []   # 用于存储解析出的bool值
                        for i in range(count):
                            current_global_bit = offset + i
                            current_byte = current_global_bit // 8
                            current_bit = current_global_bit % 8
                            result.append(bool(raw_data[current_byte] & (1 << current_bit)))
                        return result[0] if count == 1 else result

                    elif data_type == 'byte':
                        if offset + count > len(raw_data):
                            self.logger.warning(
                                f"⚠️ DB100缓存文件数据不足：需要偏移{offset}+{count}字节，实际{len(raw_data)}字节")
                        else:
                            data = raw_data[offset:offset + count]
                            return [b for b in data] if count > 1 else data[0]

                    elif data_type in ['int', 'word']:
                        total_bytes = 2 * count
                        data = self.read_db(db_number, offset, total_bytes)
                        if data is None:
                            return None

                        result = []
                        for i in range(count):
                            if data_type == 'int':
                                result.append(get_int(data, i * 2))
                            else:  # word
                                result.append(get_word(data, i * 2))
                        return result[0] if count == 1 else result

                    elif data_type in ['dint', 'dword', 'real']:
                        byte_per_data = 4
                        total_bytes = byte_per_data * count
                        if offset + total_bytes > len(raw_data):
                            self.logger.warning(
                                f"⚠️ DB100缓存文件数据不足：需要偏移{offset}+{total_bytes}字节，实际{len(raw_data)}字节")
                        else:
                            result = []
                            for i in range(count):
                                start = offset + i * byte_per_data
                                slice_data = raw_data[start:start + byte_per_data]
                                if data_type == 'dint':
                                    result.append(get_dint(slice_data, 0))
                                elif data_type == 'dword':
                                    result.append(get_dword(slice_data, 0))
                                else:  # real
                                    result.append(get_real(slice_data, 0))
                            return result[0] if count == 1 else result

                    # 1.5 不支持的数据类型
                    else:
                        self.logger.error(f"❌ 不支持的数据类型：{data_type}")
                        return None

                except Exception as e:
                    self.logger.error(f"❌ 解析DB{db_number}缓存文件数据异常（类型：{data_type}，偏移：{offset}）: {e}",
                                      exc_info=True)

            # 文件读取失败，fallback到原逻辑（内存缓存→PLC）
            self.logger.debug(f"⚠️ DB{db_number}缓存文件读取失败， fallback到内存缓存/PLC")

        # 缓存读取失败或未启用缓存，直接从PLC读取
        if not self.connected and not self.connect():
            self.logger.warning(f"Read failed: not connected to {self.ip}")
            return None

        try:
            print(f"从PLC中读取DB{db_number}的数据")
            if data_type == 'bool':
                # 对于bool，offset是位偏移
                byte_offset = offset // 8
                bit_offset = offset % 8
                # 计算需要读取的字节数
                last_bit = bit_offset + count - 1
                last_byte = last_bit // 8
                total_bytes = last_byte - byte_offset + 1

                # 读取原始字节数据
                data = self.read_db(db_number, byte_offset, total_bytes)
                if data is None:
                    return None

                # 解析bool值
                result = []
                for i in range(count):
                    curr_bit = bit_offset + i
                    byte_idx = curr_bit // 8
                    bit_idx = curr_bit % 8
                    result.append(bool(data[byte_idx] & (1 << bit_idx)))

                return result[0] if count == 1 else result

            elif data_type == 'byte':
                data = self.read_db(db_number, offset, count)
                if data is None:
                    return None
                return [data[i] for i in range(count)] if count > 1 else data[0]

            elif data_type in ['int', 'word']:

                total_bytes = 2 * count
                data = self.read_db(db_number, offset, total_bytes)
                if data is None:
                    return None

                result = []
                for i in range(count):
                    if data_type == 'int':
                        result.append(get_int(data, i * 2))
                    else:  # word
                        result.append(get_word(data, i * 2))
                return result[0] if count == 1 else result

            elif data_type in ['dint', 'dword', 'real']:
                total_bytes = 4 * count
                data = self.read_db(db_number, offset, total_bytes)
                if data is None:
                    return None

                result = []
                for i in range(count):
                    if data_type == 'dint':
                        result.append(get_dint(data, i * 4))
                    elif data_type == 'dword':
                        result.append(get_dword(data, i * 4))
                    else:  # real
                        result.append(get_real(data, i * 4))
                return result[0] if count == 1 else result

            else:
                self.logger.error(f"Unsupported data type: {data_type}")
                return None

        except Exception as e:
            self.logger.error(f"Error reading {data_type} from DB{db_number} offset {offset}: {e}")
            return None