[嵌入式]IOT Gateway MQTT 连接器配置

? ? ? ? 本文将帮助你熟悉有关iot网关中MQTT连接器的配置。在通用配置中启用该种连接器。这个连接器能够连接到外部的MQTT Broker并订阅，从而获取从设备中上报的数据，同时，连接器也可以推送来自ThingsBoard数据到MQTT Broker。

连接器配置：mqtt.json

连接器配置是一个json文件，它包含了MQTT Broker的连接信息、订阅哪些主题、如何处理数据等。

mqtt.json样例

{
  "broker": {
    "name":"Default Local Broker",
    "host":"192.168.1.100",
    "port":1883,
    "security": {
      "type": "basic",
      "username": "user",
      "password": "password"
    }
  },
  "mapping": [
    {
      "topicFilter": "/sensor/data",
      "converter": {
        "type": "json",
        "deviceNameJsonExpression": "${serialNumber}",
        "deviceTypeJsonExpression": "${sensorType}",
        "timeout": 60000,
        "attributes": [
          {
            "type": "string",
            "key": "model",
            "value": "${sensorModel}"
          }
        ],
        "timeseries": [
          {
            "type": "double",
            "key": "temperature",
            "value": "${temp}"
          },
          {
            "type": "double",
            "key": "humidity",
            "value": "${hum}"
          }
        ]
      }
    },
    {
      "topicFilter": "/sensor/+/data",
      "converter": {
        "type": "json",
        "deviceNameTopicExpression": "(?<=sensor\/)(.*?)(?=\/data)",
        "deviceTypeTopicExpression": "Thermometer",
        "timeout": 60000,
        "attributes": [
          {
            "type": "string",
            "key": "model",
            "value": "${sensorModel}"
          }
        ],
        "timeseries": [
          {
            "type": "double",
            "key": "temperature",
            "value": "${temp}"
          },
          {
            "type": "double",
            "key": "humidity",
            "value": "${hum}"
          }
        ]
      }
    },
    {
      "topicFilter": "/custom/sensors/+",
      "converter": {
        "type": "custom",
        "extension": "CustomMqttUplinkConverter",
        "extension-config": {
            "temperatureBytes" : 2,
            "humidityBytes" :  2,
            "batteryLevelBytes" : 1
        }
      }
    }
  ],
  "connectRequests": [
    {
      "topicFilter": "sensor/connect",
      "deviceNameJsonExpression": "${SerialNumber}"
    },
    {
      "topicFilter": "sensor/+/connect",
      "deviceNameTopicExpression": "(?<=sensor\/)(.*?)(?=\/connect)"
    }
  ],
  "disconnectRequests": [
    {
      "topicFilter": "sensor/disconnect",
      "deviceNameJsonExpression": "${SerialNumber}"
    },
    {
      "topicFilter": "sensor/+/disconnect",
      "deviceNameTopicExpression": "(?<=sensor\/)(.*?)(?=\/disconnect)"
    }
  ],
  "attributeUpdates": [
    {
      "deviceNameFilter": "SmartMeter.*",
      "attributeFilter": "uploadFrequency",
      "topicExpression": "sensor/${deviceName}/${attributeKey}",
      "valueExpression": "{\"${attributeKey}\":\"${attributeValue}\"}"
    }
  ],
  "serverSideRpc": [
    {
      "deviceNameFilter": ".*",
      "methodFilter": "echo",
      "requestTopicExpression": "sensor/${deviceName}/request/${methodName}/${requestId}",
      "responseTopicExpression": "sensor/${deviceName}/response/${methodName}/${requestId}",
      "responseTimeout": 10000,
      "valueExpression": "${params}"
    },
    {
      "deviceNameFilter": ".*",
      "methodFilter": "no-reply",
      "requestTopicExpression": "sensor/${deviceName}/request/${methodName}/${requestId}",
      "valueExpression": "${params}"
    }
  ]
}

配置中broker模块

配置中的security模块

该模块配置提供了mqtt broker客户端授权的访问信息

三种配置：Basic，Anonymous，Certificates

Basic

配置如下所示：

    "security": {
      "type": "basic",
      "username": "username",
      "password": "password"
    }

Anonymous

配置如下所示：

    "security": {
      "type": "anonymous"
    }

Certificates

配置代码如下：

  "security":{
    "caCert": "/etc/thingsboard-gateway/ca.pem",
    "privateKey": "/etc/thingsboard-gateway/privateKey.pem",
    "cert": "/etc/thingsboard-gateway/certificate.pem"
  }

配置文件中的mapping模块

该配置包含一组主题数组，网关将会订阅这些主题并处理设备上报的数据

topicFilter支持特殊字符，其中包括：‘#’ 和 ‘+’，这样就可以实现订阅多个主题

配置中的转换器模块

mqtt转换器类型： json和custom

json

备注：实际attributes和telemetry中的参数可能与上述参数不同，但具有相同的结构

Example 1 对应的代码如下：

    {
      "topicFilter": "/sensor/data",
      "converter": {
        "type": "json",
        "deviceNameJsonExpression": "${serialNumber}",
        "deviceTypeJsonExpression": "${sensorType}",
        "timeout": 60000,
        "attributes": [
          {
            "type": "string",
            "key": "model",
            "value": "${sensorModel}"
          }
        ],
        "timeseries": [
          {
            "type": "double",
            "key": "temperature",
            "value": "${temp}"
          },
          {
            "type": "double",
            "key": "humidity",
            "value": "${hum}"
          }
        ]
      }
    }

Example 2 对应的代码：

    {
      "topicFilter": "/sensor/+/data",
      "converter": {
        "type": "json",
        "deviceNameTopicExpression": "(?<=sensor\/)(.*?)(?=\/data)",
        "deviceTypeTopicExpression": "Thermometer",
        "timeout": 60000,
        "attributes": [
          {
            "type": "string",
            "key": "model",
            "value": "${sensorModel}"
          }
        ],
        "timeseries": [
          {
            "type": "double",
            "key": "temperature",
            "value": "${temp}"
          },
          {
            "type": "double",
            "key": "humidity",
            "value": "${hum}"
          }
        ]
      }
    }

custom

自定义转换器是为某些设备编写的转换器，如下所示：

配置代码如下：

      "converter": {
        "type": "custom",
        "extension": "CustomMqttUplinkConverter",
        "extension-config": {
            "temperatureBytes" : 2,
            "humidityBytes" :  2,
            "batteryLevelBytes" : 1
        }
      }

配置中的“connectRequests”模块

ThingsBoard允许向设备发送RPC命令和有关设备属性更新的通知。但是为了发生这些指令，平台需要知道目标设备是否已连接和它使用的什么网关或者会话连接设备。如果您的设备不断地发送遥测数据，ThingsBoard已经知道怎么推送通知了。如果您的设备刚刚连接到MQTT broker冰鞋等待指令或者更新，您需要向网关发送消息并通知设备已连接到mqtt broker。

1. 设备名称在消息体中

2. 设备名称在主题地址中

配置代码如下所示：

  "connectRequests": [
    {
      "topicFilter": "sensors/connect",
      "deviceNameJsonExpression": "${$.SerialNumber}"
    },
    {
      "topicFilter": "sensor/+/connect",
      "deviceNameTopicExpression": "(?<=sensor\/)(.*?)(?=\/connect)"
    }
  ]