mqtt应用学习

一 网络连接状态：

如果是无线（如esp32的WIFI_AT）初始化网络成功连接后Connect_Status=1,然后在mqtt开始前进行超时判断while（Connect_Status==0）{deley(2s)}

二 以umqtt为例：

2.0配置mqtt_client参数进行连接

int umqtt_ex_start(void)
{
    LOG_D(" umqtt example start!");
    struct umqtt_info umqtt_info = { 0 };
    umqtt_info.uri = MQTT_URI;
    umqtt_info.client_id="RTU00002";
    umqtt_info.reconnect_interval=2;

    m_umqtt_client = umqtt_create(&umqtt_info);/*用umqtt_info配置mqtt连接客户端参数*/
    if (m_umqtt_client == RT_NULL)
    {
       LOG_E(" umqtt client create failed!");
       return -1;
    }
    umqtt_control(m_umqtt_client, UMQTT_CMD_EVT_CB, user_callback);

    if (umqtt_start(m_umqtt_client) >= 0)
    {
       LOG_I(" umqtt start success!");
       is_started = 1;
       return 0;
    }
    else
    {
       m_umqtt_client = RT_NULL;
       LOG_E(" umqtt start failed!");
       is_started = 0;
       return -1;
    }       
}

 

2.1周期发布

 static void app_mqtt_thread_entry(void *parameter)
{   
    while(connected==0)
    {
        rt_thread_mdelay(3000);
    }
    umqtt_ex_start();   
    while(1)
    {
        umqtt_ex_publish();/*周期发布*/
        rt_thread_mdelay(1000);
    }
}

2.2