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5.实现mqtt转发

说明

举例现在有两个通道需要转发，协议为任意两个采集协议，转发为mqtt转发，功能码为实时数据。

接下来我们用python来实现数据的转发。

创建转发工程

提示

通过python转发将不再创建通道。但需在代码中配置IP，端口参数。

配置mqtt转发IP,PORT参数

使用paho-mqtt模块，使用mqtt_connect定义连接服务器参数。

提示

根据需要，自行按照mqttClient.tls_set()函数添加证书。添加证书后必须执行mqttClient.tls_insecure_set(True)语句。

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    #==========================================================
    def mqtt_connect():
        client_id = time.strftime('%Y%m%d%H%M%S', time.localtime(time.time()))
        mqttClient = mqtt.Client(client_id, transport='tcp')
        mqttClient.on_connect = on_connect
        host = "47.97.230.45"
        port = 4020
        mqttClient.username_pw_set("", "")
        mqttClient.tls_set(ca_certs='/data/project/1008-ca.pem', certfile='/data/project/1008.pem', keyfile='/data/project/1008.key')
        mqttClient.tls_insecure_set(True)
        mqttClient.connect(host, port, 60)
        mqttClient.loop_start()
        return mqttClient

加载工程参数

选择需转发的采集通道

创建一个列表，列表中输入需要转发的通道名称，要求字符串格式，并用逗号隔开。根据实际情况自行添加，示例为两个采集通道。如下述片段所示：

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    #==========================================================
    chl_list = ['chal_LQ', 'python采集通道']   # 创建需要转发的通道

取设备参数

首先使用get_dev_count函数得到通道下的设备数量，然后创建相应数量的设备数组，再使用get_dev_array函数取得设备参数。

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    #==========================================================
    #根据采集通道取其下的设备信息
    dev_count = c4py.get_dev_count(chl_name.encode())
    print("通道名称:"+ chl_name + "; dev count:" + str(dev_count))
    # 创建一个长度为 dev_count 的数组
    device_info_array = (c4py.DeviceInfo * dev_count)()
    c4py.get_dev_array(chl_name.encode(), device_info_array)

取测点参数

首先使用get_tag_count函数得到通道下的设备数量，然后创建相应数量的设备数组，再使用get_tag_array函数取得设备参数。

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    #==========================================================
    #根据设备取其下的测点信息
    tag_count = c4py.get_tag_count(device_info.dev_name)
    print("设备名称:"+ device_info.dev_name.decode() + ";tag count:"+ str(tag_count))
    # 创建一个长度为 tag_count 的数组
    tag_info_array = (c4py.TagInfo * tag_count)()
    c4py.get_tag_array(device_info.dev_name, tag_info_array)

转发

构造转发报文

通过mqtt接口文档构造消息体。示例中需要的参数有"tp","sn","tm","chl_name","dev"。实际根据所用mqtt的数据格式自行修改。

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# 构造mqtt发布数据
def build_send_buff(type, sn):
    dev = []
    chl_list = ['chal_LQ', 'python采集通道']   # 创建需要转发的通道
    # 遍历通道
    for chl_name in chl_list:
        timestr = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))
        #根据采集通道取其下的设备信息
        dev_count = c4py.get_dev_count(chl_name.encode())
        print("通道名称:"+ chl_name + "; dev count:" + str(dev_count))
        # 创建一个长度为 dev_count 的数组
        device_info_array = (c4py.DeviceInfo * dev_count)()
        c4py.get_dev_array(chl_name.encode(), device_info_array)
        #==========================================================
        # 遍历通道下的设备
        for device_info in device_info_array:
            tag_count = c4py.get_tag_count(device_info.dev_name)
            print("设备名称:"+ device_info.dev_name.decode() + ";tag count:"+ str(tag_count))
            # 创建一个长度为 tag_count 的数组
            tag_info_array = (c4py.TagInfo * tag_count)()
            c4py.get_tag_array(device_info.dev_name, tag_info_array)
            tag = []
            # 遍历设备下的测点
            for tag_info in tag_info_array:
                # 获取测点值
                tag_value = ctypes.c_float.from_address(ctypes.addressof(tag_info.p_tag_value.contents)).value
                # 获取测点质量
                tag_qos = ctypes.c_int.from_address(ctypes.addressof(tag_info.p_tag_quality.contents)).value
                if tag_qos == 0:
                    q = 1
                else:
                    q = 0
                tag.append({'name': tag_info.base.tag_name.decode(), 'q': q, 'v': tag_value})
            dev.append({'name': device_info.dev_name.decode(), 'tag': tag})
    send_buff = {'tp': type,'sn': sn, 'tm': timestr, 'chl_name': "python转发通道", 'dev': dev}
    return send_buff

用mqtt.fx连接服务器后订阅到的消息如下图：

其它优化

1、原本读取到的质量为好时值为0，质量坏时值为100。现改成好为1，坏为0.

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    # 获取测点质量
    tag_qos = ctypes.c_int.from_address(ctypes.addressof(tag_info.p_tag_quality.contents)).value
    if tag_qos == 0:
        q = 1
    else:
        q = 0
    tag.append({'name': tag_info.base.tag_name.decode(), 'q': q, 'v': tag_value})

2、注册系统信号处理函数，来接收程序退出消息，以释放资源。

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#系统信号
app_exit_signal = 0

#系统信号处理函数
def handle_sigterm(signum, frame):
    global app_exit_signal
    app_exit_signal = signum

# 注册信号处理函数
signal.signal(signal.SIGTERM, handle_sigterm)
signal.signal(signal.SIGUSR1, handle_sigterm)

c4py.py_load_so()
c4py.global_init()
while True:
    #do something
    if app_exit_signal != 0:
        print("app exit signal: [{}]".format(app_exit_signal))
        break
#释放资源
c4py.global_release()

完整源码

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import ctypes
import c4py
import signal
import ptvsd
import paho.mqtt.client as mqtt
import json
import time

# 系统信号
app_exit_signal = 0

# 系统信号处理函数
def handle_sigterm(signum, frame):
    global app_exit_signal
    app_exit_signal = signum


# 回调函数，获取mqtt连接状态
def on_connect(client, userdata, flags, rc):
    rc_status = ["连接成功", "协议版本错误", "无效客户端", "服务器无法使用", "用户名密码错误", "无授权"]
    result = "connet:" + rc_status[rc]
    if rc == 1:
        # 将通道状态设置为正常
        print("connect:" + rc_status[rc])
        c4py.set_chl_status(chl_name.encode(),c4py.RUN_STAT_NORMAL)
    else:
        print("connect:" + rc_status[rc])

# 连接服务器
def mqtt_connect():
    client_id = time.strftime('%Y%m%d%H%M%S', time.localtime(time.time()))
    mqttClient = mqtt.Client(client_id, transport='tcp')
    mqttClient.on_connect = on_connect
    host = "47.97.230.45"
    port = 4020
    mqttClient.username_pw_set("", "")
    # mqttClient.tls_insecure_set(True)
    mqttClient.tls_set(ca_certs='/data/project/1008-ca.pem', certfile='/data/project/1008.pem', keyfile='/data/project/1008.key')
    mqttClient.tls_insecure_set(True)
    mqttClient.connect(host, port, 60)
    mqttClient.loop_start()

    return mqttClient


# 构造mqtt发布数据
def build_send_buff(type, sn):
    dev = []
    chl_list = ['chal_LQ', 'python采集通道']   # 创建需要转发的通道
    # 遍历通道
    for chl_name in chl_list:
        timestr = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(time.time()))
        #根据采集通道取其下的设备信息
        dev_count = c4py.get_dev_count(chl_name.encode())
        print("通道名称:"+ chl_name + "; dev count:" + str(dev_count))
        # 创建一个长度为 dev_count 的数组
        device_info_array = (c4py.DeviceInfo * dev_count)()
        c4py.get_dev_array(chl_name.encode(), device_info_array)
        #==========================================================
        # 遍历通道下的设备
        for device_info in device_info_array:
            tag_count = c4py.get_tag_count(device_info.dev_name)
            print("设备名称:"+ device_info.dev_name.decode() + ";tag count:"+ str(tag_count))
            # 创建一个长度为 tag_count 的数组
            tag_info_array = (c4py.TagInfo * tag_count)()
            c4py.get_tag_array(device_info.dev_name, tag_info_array)
            tag = []
            # 遍历设备下的测点
            for tag_info in tag_info_array:
                # 获取测点值
                tag_value = ctypes.c_float.from_address(ctypes.addressof(tag_info.p_tag_value.contents)).value
                # 获取测点质量
                tag_qos = ctypes.c_int.from_address(ctypes.addressof(tag_info.p_tag_quality.contents)).value
                if tag_qos == 0:
                    q = 1
                else:
                    q = 0
                tag.append({'name': tag_info.base.tag_name.decode(), 'q': q, 'v': tag_value})
            dev.append({'name': device_info.dev_name.decode(), 'tag': tag})
    send_buff = {'tp': type,'sn': sn, 'tm': timestr, 'chl_name': "python转发通道", 'dev': dev}
    return send_buff



if __name__ == "__main__":
    # 注册信号处理函数
    signal.signal(signal.SIGTERM, handle_sigterm)
    signal.signal(signal.SIGUSR1, handle_sigterm)
    #==========================================================
    #启动调试，等待调试器附加，正式运行时注释下述两行
    ptvsd.enable_attach(address=('0.0.0.0', 5678))
    ptvsd.wait_for_attach()
    #==========================================================
    #库初始化
    c4py.py_load_so()
    print("c4py version:" + c4py.C4PY_VERSION)
    c4py.global_init()
    #==========================================================
    chl_name = "python采集通道"
    # 设置参数 连接mqtt服务器
    mqttClient = mqtt_connect()
    c4py.set_chl_status(chl_name.encode(),c4py.RUN_STAT_NORMAL)
    print("通道名称:" + chl_name + ";IP端口:" + "47.97.230.45:4020" + ";超時:" + str(5))
    sn = '80C306D021964E03'
    type = 2    
    while True:
        send_buff = build_send_buff(type, sn)
        print(json.dumps(send_buff))
        # 发布
        mqttClient.publish("/lqgyy/pub/{}".format(sn), json.dumps(send_buff), 2)
        c4py.msleep(5000)

        if app_exit_signal != 0:
            print("app exit signal: [{}]".format(app_exit_signal))
            break

    # 关闭连接
    mqttClient.loop_stop()
    c4py.global_release()