Willin: Azure Node.js IoT Hub开发指南

内容简介：Willin: Azure Node.js IoT Hub开发指南

IOT Hub应用实际开发过程中的一些注意细节

资源:

• 创建设备: https://www.npmjs.com/package/azure-iothub
• IoT Hub(基于Event Hubs)消息管理: https://www.npmjs.com/package/azure-event-hubs
• 开发调试工具: https://www.npmjs.com/package/iothub-explorer

简单发送接收示例

1. 注册设备

const iothub = require('azure-iothub');

const registry = iothub.Registry.fromConnectionString('[connectionString]');

const device = new iothub.Device(null);
device.deviceId = '[deviceId]';

function printDeviceInfo(err, deviceInfo, res){
  if (deviceInfo) {
    console.log(JSON.stringify(deviceInfo, null, 2));
    console.log(`Device id:${deviceInfo.deviceId}`);
    console.log(`Device key:${deviceInfo.authentication.symmetricKey.primaryKey}`);
  }
}

// 删除设备 registry.delete(deviceId, (err, deviceInfo, res) => {});
registry.create(device, (err, deviceInfo, res) => {
  if (err) {
    registry.get(device.deviceId, printDeviceInfo);
  }
  if (deviceInfo) {
    printDeviceInfo(err, deviceInfo, res);
  }
});

2. 模拟设备发送消息

const clientFromConnectionString = require('azure-iot-device-mqtt').clientFromConnectionString;
const Message = require('azure-iot-device').Message;

const connectionString = 'HostName=[修改连接主机];DeviceId=[deviceID];SharedAccessKey=[连接密钥]';

const client = clientFromConnectionString(connectionString);

function printResultFor(op){
  return function printResult(err, res){
    if (err) console.log(`${op}error:${err.toString()}`);
    if (res) console.log(`${op}status:${res.constructor.name}`);
  };
}

const connectCallback = function(err){
  if (err) {
    console.log(`Could not connect:${err}`);
  } else {
    console.log('Client connected');

    // Create a message and send it to the IoT Hub every second
    setInterval(()=> {
      const windSpeed = 10 + (Math.random() * 4);
      const data = JSON.stringify({ deviceId: 'myFirstNodeDevice', windSpeed });
      const message = new Message(data);
      console.log(`Sending message:${message.getData()}`);
      client.sendEvent(message, printResultFor('send'));
    }, 1000);
  }
};

client.open(connectCallback);

3. 服务器端接收消息

const EventHubClient = require('azure-event-hubs').Client;

const connectionString = 'HostName=[修改连接主机];SharedAccessKeyName=iothubowner;SharedAccessKey=[修改连接密钥]';

const printError = function(err){
  console.log(err.message);
};

const printMessage = function(message){
  console.log('Message received: ');
  console.log(JSON.stringify(message.body));
  Object.getOwnPropertyNames(message).forEach((x) => {
    console.log(x, message[x]);
  });
  console.log('');
};

const client = EventHubClient.fromConnectionString(connectionString);

client.open()
    .then(client.getPartitionIds.bind(client))
    .then(partitionIds=> partitionIds.map(partitionId=> client.createReceiver('$Default', partitionId, { startAfterTime: Date.now()}).then((receiver) => {
      console.log(`Created partition receiver:${partitionId}`);
      receiver.on('errorReceived', printError);
      receiver.on('message', printMessage);
    })))
    .catch(printError);

注意:

• 客户端传的 properties ,在消息体中是 message.applicationProperties
• message 包含的属性如下:

[ 'partitionKey',
  'body',
  'enqueuedTimeUtc',
  'offset',
  'properties',
  'applicationProperties',
  'sequenceNumber',
  'annotations',
  'systemProperties' ]

消息体示例:

Message received:
partitionKey undefined
body { deviceId: 'myFirstNodeDevice', windSpeed: 10.51685587945142 }
enqueuedTimeUtc 2017-06-13T01:21:02.519Z
offset 73240
properties undefined
applicationProperties { asdf: 'asdfz' }
sequenceNumber 182
annotations { 'x-opt-sequence-number': 182,
  'x-opt-offset': '73240',
  'x-opt-enqueued-time': 2017-06-13T01:21:02.519Z,
  'iothub-connection-device-id': 'myFirstNodeDevice',
  'iothub-connection-auth-method': '{ "scope": "device", "type": "sas", "issuer": "iothub" }',
  'iothub-connection-auth-generation-id': 'xxxxxxx',
  'iothub-enqueuedtime': 2017-06-13T01:21:02.786Z,
  'iothub-message-source': 'Telemetry' }
systemProperties undefined

配置路由(需要Event Hubs)

1. 创建Event Hubs

2. 从事件中心创建实体

3. 获取连接字符串

点击进入已创建的实体

不要从别处获得连接字符串,因为可能无法连接. 最终获得的连接字符串应当包含 EntityPath 字段,类似:

Endpoint=sb://xxxx.servicebus.chinacloudapi.cn/;SharedAccessKeyName=iothubroutes_xxxx;SharedAccessKey=xxxx;EntityPath=xxxx

4. 创建Endpoint

将 Event Hubs 里的事件关联到 IoT Hub

5. 创建路由

示例代码

1. 修改刚才的发送示例

const clientFromConnectionString = require('azure-iot-device-mqtt').clientFromConnectionString;
const Message = require('azure-iot-device').Message;

const connectionString = 'HostName=[修改连接主机];DeviceId=[deviceID];SharedAccessKey=[连接密钥]';

const client = clientFromConnectionString(connectionString);

function printResultFor(op){
  return function printResult(err, res){
    if (err) console.log(`${op}error:${err.toString()}`);
    if (res) console.log(`${op}status:${res.constructor.name}`);
  };
}

const connectCallback = function(err){
  if (err) {
    console.log(`Could not connect:${err}`);
  } else {
    console.log('Client connected');

    // Create a message and send it to the IoT Hub every second
    setInterval(()=> {
      const windSpeed = 10 + (Math.random() * 4);
      const data = JSON.stringify({ deviceId: 'myFirstNodeDevice', windSpeed });
      const message = new Message(data);
      // 随机发送到路由或默认事件上
      if (Math.round(Math.random()) === 1) {
        message.properties.add('route', 'test');
      }
      console.log(`Sending message:${message.getData()}`);
      client.sendEvent(message, printResultFor('send'));
    }, 1000);
  }
};

client.open(connectCallback);

2. IoT Hub 侦听启动

无需修改,直接启动

3. Event Hubs 侦听启动

复制 IoT Hub 侦听源码,修改连接字符串:

const EventHubClient = require('azure-event-hubs').Client;

// const connectionString = 'HostName=[修改连接主机];SharedAccessKeyName=iothubowner;SharedAccessKey=[修改连接密钥]';
const connectionString = 'Endpoint=[sb://修改连接主机.servicebus.chinacloudapi.cn/];SharedAccessKeyName=[修改连接策略];SharedAccessKey=[x修改连接密钥];EntityPath=[事件实体]'

const printError = function(err){
  console.log(err.message);
};

const printMessage = function(message){
  console.log('Message received: ');
  console.log(JSON.stringify(message.body));
  console.log(message);
  console.log('');
};

const client = EventHubClient.fromConnectionString(connectionString);

client.open()
    .then(client.getPartitionIds.bind(client))
    .then(partitionIds=> partitionIds.map(partitionId=> client.createReceiver('$Default', partitionId, { startAfterTime: Date.now()}).then((receiver) => {
      console.log(`Created partition receiver:${partitionId}`);
      receiver.on('errorReceived', printError);
      receiver.on('message', printMessage);
    })))
    .catch(printError);

测试结果

• 发送到默认路由的,只能被IoT Hub侦听应用捕获.
• 发送到刚才配置的测试路由的,只能被Event Hubs侦听应用捕获.

至此,完成路由转发.

以上所述就是小编给大家介绍的《Willin: Azure Node.js IoT Hub开发指南》，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持！

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