ThingsBoard通过MQTT发送属性数据

MQTT基础

客户端

MQTT连接

属性上传API

案例

MQTT基础

MQTT是一种轻量级的发布-订阅消息传递协议，它可能最适合各种物联网设备。

你可以在此处找到有关MQTT的更多信息，ThingsBoard服务器支持QoS级别0（最多一次）和QoS级别1（至少一次）以及一组预定义主题的MQTT代理。

客户端

你可以在网上找到大量的MQTT客户端库，本文中的示例将基于Mosquitto和MQTT.js您可以使用我们的Hello World指南中的说明。

MQTT连接

我们将在本文中使用令牌凭据对进行设备访问，这些凭证稍后将称为$ACCESS_TOKEN应用程序需要发送用户名包含$ACCESS_TOKEN的MQTT CONNECT消息。

连接状态码说明：

0x00 连接成功 - 成功连接
0x04 连接失败 - 用户名或密码错误。
0x05 连接未授权 - -用户名包含无效的 $ACCESS_TOKEN。

Key-value格式

ThingsBoard支持以JSON格式的key-value字符串值可以是string、bool、float、long或者二进制格式的序列化字符串；

{
 "stringKey":"value1", 
 "booleanKey":true, 
 "doubleKey":42.0, 
 "longKey":73, 
 "jsonKey": {
    "someNumber": 42,
    "someArray": [1,2,3],
    "someNestedObject": {"key": "value"}
 }
}

属性上传API

发布遥测数据到ThingsBoard服务端必须PUBLISH消息发送到下面主题：

v1/devices/me/attributes

支持的最简单的数据格式是：

{"key1":"value1"}

# Publish client-side attributes update. Replace $THINGSBOARD_HOST_NAME and $ACCESS_TOKEN with corresponding values.
mosquitto_pub -d -h "$THINGSBOARD_HOST_NAME" -t "v1/devices/me/attributes" -u "$ACCESS_TOKEN" -m "{"attribute1": "value1", "attribute2": true}"
# For example, $THINGSBOARD_HOST_NAME reference live demo server, $ACCESS_TOKEN is ABC123:
mosquitto_pub -d -h "demo.thingsboard.io" -t "v1/devices/me/attributes" -u "ABC123" -m "{"attribute1": "value1", "attribute2": true}"

# Publish client-side attributes update from file. Replace $THINGSBOARD_HOST_NAME and $ACCESS_TOKEN with corresponding values.
mosquitto_pub -d -h "$THINGSBOARD_HOST_NAME" -t "v1/devices/me/attributes" -u "$ACCESS_TOKEN" -f "new-attributes-values.json"
# For example, $THINGSBOARD_HOST_NAME reference live demo server, $ACCESS_TOKEN is ABC123:
mosquitto_pub -d -h "demo.thingsboard.io" -t "v1/devices/me/attributes" -u "ABC123" -f "new-attributes-values.json"


# Publish client-side attributes update from file. Replace $THINGSBOARD_HOST_NAME and $ACCESS_TOKEN with corresponding values.
mosquitto_pub -d -h "$THINGSBOARD_HOST_NAME" -t "v1/devices/me/attributes" -u "$ACCESS_TOKEN" -f "new-attributes-values.json"
# For example, $THINGSBOARD_HOST_NAME reference live demo server, $ACCESS_TOKEN is ABC123:
mosquitto_pub -d -h "demo.thingsboard.io" -t "v1/devices/me/attributes" -u "ABC123" -f "new-attributes-values.json"


# Publish client-side attributes update from file. Replace $THINGSBOARD_HOST_NAME and $ACCESS_TOKEN with corresponding values.
mosquitto_pub -d -h "$THINGSBOARD_HOST_NAME" -t "v1/devices/me/attributes" -u "$ACCESS_TOKEN" -f "new-attributes-values.json"
# For example, $THINGSBOARD_HOST_NAME reference live demo server, $ACCESS_TOKEN is ABC123:
mosquitto_pub -d -h "demo.thingsboard.io" -t "v1/devices/me/attributes" -u "ABC123" -f "new-attributes-values.json"

# Publish client-side attributes update. Replace $THINGSBOARD_HOST_NAME and $ACCESS_TOKEN with corresponding values.
cat new-attributes-values.json | mqtt pub -d -h "$THINGSBOARD_HOST_NAME" -t "v1/devices/me/attributes" -u '$ACCESS_TOKEN' -s -m ""
# For example, $THINGSBOARD_HOST_NAME reference live demo server, $ACCESS_TOKEN is ABC123:
cat new-attributes-values.json | mqtt pub -d -h "demo.thingsboard.io" -t "v1/devices/me/attributes" -u 'ABC123' -s -m ""

{
  "attribute1": "value1",
  "attribute2": true,
  "attribute3": 42.0,
  "attribute4": 73,
  "attribute5": {
    "someNumber": 42,
    "someArray": [1,2,3],
    "someNestedObject": {"key": "value"}
  }
}

通过服务端获取属性值

通过ThingsBoard服务端获取客户端属性或共享属性必须PUBLISH消息到下面主题:

v1/devices/me/attributes/request/$request_id

其中$request_id表示整数的请求标识符。

在发送带有请求的PUBLISH消息之前客户端需要订阅。

v1/devices/me/attributes/response/+

以下示例是用javascript基于mqtt.js编写的代码。
命令行示例不可用因为订阅和发布需要在同一mqtt会话中进行。

通过设备的访问令牌替换$ACCESS_TOKEN并将”mqtt-js-attributes-request.js”文件中的主机名替换为”demo.thingsboard.io”。
在此示例中主机名参考演示服务器。

export TOKEN=$ACCESS_TOKEN
node mqtt-js-attributes-request.js

var mqtt = require('mqtt')
var client  = mqtt.connect('mqtt://demo.thingsboard.io',{
    username: process.env.TOKEN
})

client.on('connect', function () {
    console.log('connected')
    client.subscribe('v1/devices/me/attributes/response/+')
    client.publish('v1/devices/me/attributes/request/1', '{"clientKeys":"attribute1,attribute2", "sharedKeys":"shared1,shared2"}')
})

client.on('message', function (topic, message) {
    console.log('response.topic: ' + topic)
    console.log('response.body: ' + message.toString())
    client.end()
})