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IoT 即插即用服务开发人员指南

借助 IoT 即插即用,你可以生成将功能播发到 Azure IoT 应用程序的 IoT 设备。 当客户将 IoT 即插即用设备连接到已启用 IoT 即插即用的应用程序时,无需手动配置。

借助 IoT 即插即用,你可以使用已通过 IoT 中心公布其模型 ID 的设备。 例如,你可以直接访问设备的属性和命令。

若要使用连接到 IoT 中心的 IoT 即插即用设备,请使用 IoT 服务 SDK 之一:

服务 SDK

使用解决方案中的 Azure IoT 服务 SDK 与设备和模块进行交互。 例如,可以使用服务 SDK 来读取和更新孪生体属性以及调用命令。 支持的语言包括 C#、Java、Node.js 和 Python。

服务 SDK 允许你从解决方案(如桌面或 Web 应用程序)访问设备信息。 服务 SDK 包括两个可用于检索模型 ID 的命名空间和对象模型:

  • IoT 中心服务客户端。 此服务将模型 ID 公开为设备孪生体属性。

  • 数字孪生体客户端。 新的数字孪生体 API 在数字孪生体定义语言 (DTDL) 模型构造(例如组件、属性和命令)上运行。 数字孪生体 API 使解决方案开发者可以更轻松地创建 IoT 即插即用解决方案。

还可以使用以下资源:

IoT 中心服务客户端示例

本部分介绍的 C# 示例使用 IoT 中心服务客户端以及 RegistryManager 类和 ServiceClient 类 。 使用 RegistryManager 类通过设备孪生与设备状态交互。 还可以使用 RegistryManager 类在 IoT 中心查询设备注册。 使用 ServiceClient 类在设备上调用命令。 设备的 DTDL 模型定义了设备实现的属性和命令。 在代码片段中,deviceTwinId 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取设备孪生和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的设备孪生和模型 ID,请执行以下命令:

RegistryManager registryManager = RegistryManager.CreateFromConnectionString(parameters.HubConnectionString);

Twin twin = await registryManager.GetTwinAsync(deviceTwinId);
Console.WriteLine($"Device twin: \n{JsonConvert.SerializeObject(twin, Formatting.Indented)}");
Console.WriteLine($"Model ID: {twin.ModelId}.");

更新设备孪生

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 此示例演示你需要如何在更新孪生体之前获取其 ETag。 在设备的默认组件中定义该属性:

Twin twin = await registryManager.GetTwinAsync(deviceTwinId);

int desiredTargetTemperature = 60;

// Update the twin
var twinPatch = new Twin();
twinPatch.Properties.Desired["targetTemperature"] = desiredTargetTemperature;

Console.WriteLine($"Update the targetTemperature property to {desiredTargetTemperature}.");

await registryManager.UpdateTwinAsync(deviceTwinId, twinPatch, twin.ETag);

以下代码片段演示如何更新组件上的 targetTemperature 属性。 此示例演示你需要如何在更新孪生体之前获取其 ETag。 在 Thermostat1 组件中定义该属性:

Twin twin = await registryManager.GetTwinAsync(deviceTwinId);

int desiredTargetTemperature = 60;

var twinPatch = CreatePropertyPatch("targetTemperature", desiredTargetTemperature, "thermostat1");

await registryManager.UpdateTwinAsync(deviceTwinId, twinPatch, twin.ETag);

// ...

private static Twin CreatePropertyPatch(string propertyName, object propertyValue, string componentName)
{
    var twinPatch = new Twin();
    twinPatch.Properties.Desired[componentName] = new
    {
        __t = "c"
    };
    twinPatch.Properties.Desired[componentName][propertyName] = JsonConvert.SerializeObject(propertyValue);
    return twinPatch;
}

对于组件中的属性,属性补丁类似于以下示例:

{
"sampleComponentName":
  {
    "__t": "c",
    "samplePropertyName": 20
  }
}

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

ServiceClient serviceClient = ServiceClient.CreateFromConnectionString(parameters.HubConnectionString);

var commandInvocation = new CloudToDeviceMethod("getMaxMinReport") { ResponseTimeout = TimeSpan.FromSeconds(30) };

// Set command payload
DateTimeOffset since = DateTimeOffset.Now.Subtract(TimeSpan.FromMinutes(2));
string componentCommandPayload = JsonConvert.SerializeObject(since);
commandInvocation.SetPayloadJson(componentCommandPayload);

try
{
  CloudToDeviceMethodResult result = await serviceClient.InvokeDeviceMethodAsync(deviceTwinId, commandInvocation);

  Console.WriteLine($"Command getMaxMinReport was invoked." +
      $"\nDevice returned status: {result.Status}. \nReport: {result.GetPayloadAsJson()}");
}
catch (DeviceNotFoundException)
{
    Console.WriteLine($"Unable to execute command getMaxMinReport on {deviceTwinId}.";
}

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 Thermostat1 组件中定义该命令:

// Create command name to invoke for component. The command is formatted as <component name>*<command name>
string commandToInvoke = "thermostat1*getMaxMinReport";
var commandInvocation = new CloudToDeviceMethod(commandToInvoke) { ResponseTimeout = TimeSpan.FromSeconds(30) };

// Set command payload
DateTimeOffset since = DateTimeOffset.Now.Subtract(TimeSpan.FromMinutes(2));
string componentCommandPayload = JsonConvert.SerializeObject(since);
commandInvocation.SetPayloadJson(componentCommandPayload);

try
{
    CloudToDeviceMethodResult result = await serviceClient.InvokeDeviceMethodAsync(deviceTwinId, commandInvocation);
    Console.WriteLine($"Command getMaxMinReport was invoked on component thermostat1." +
        $"\nDevice returned status: {result.Status}. \nReport: {result.GetPayloadAsJson()}");
}
catch (DeviceNotFoundException)
{
    Console.WriteLine("Unable to execute command getMaxMinReport on component thermostat1.");
}

IoT 中心数字孪生体示例

使用 DigitalTwinClient 类通过数字孪生体与设备状态交互。 设备的 DTDL 模型定义了设备实现的属性和命令。

本部分演示有关使用数字孪生 API 的 C# 示例。 以下代码片段使用以下类来表示恒温器和温度控制器设备的数字孪生体:

using Microsoft.Azure.Devices.Serialization;
using Newtonsoft.Json;
using System;

namespace Microsoft.Azure.Devices.Samples
{
  internal class ThermostatTwin : BasicDigitalTwin
  {
    [JsonProperty("$metadata")]
    public new ThermostatMetadata Metadata { get; set; }

    [JsonProperty("maxTempSinceLastReboot")]
    public double? MaxTempSinceLastReboot { get; set; }

    [JsonProperty("targetTemperature")]
    public double? TargetTemperature { get; set; }
  }

  internal class ThermostatMetadata : DigitalTwinMetadata
  {
    [JsonProperty("maxTempSinceLastReboot")]
    public ReportedPropertyMetadata MaxTempSinceLastReboot { get; set; }

    [JsonProperty("targetTemperature")]
    public WritableProperty TargetTemperature { get; set; }
  }

  internal class ReportedPropertyMetadata
  {
    [JsonProperty("lastUpdateTime")]
    public DateTimeOffset LastUpdateTime { get; set; }
  }

  internal class TemperatureControllerTwin : BasicDigitalTwin
  {
    [JsonProperty("$metadata")]
    public new TemperatureControllerMetadata Metadata { get; set; }

    [JsonProperty("serialNumber")]
    public string SerialNumber { get; set; }

    [JsonProperty("thermostat1")]
    public ThermostatTwin Thermostat1 { get; set; }

    [JsonProperty("thermostat2")]
    public ThermostatTwin Thermostat2 { get; set; }
  }

  internal class TemperatureControllerMetadata : DigitalTwinMetadata
  {
    [JsonProperty("serialNumber")]
    public ReportedPropertyMetadata SerialNumber { get; set; }

    [JsonProperty("thermostat1")]
    public WritableProperty Thermostat1 { get; set; }

    [JsonProperty("thermostat2")]
    public WritableProperty Thermostat2 { get; set; }
  }
}

digitalTwinId 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取数字孪生体和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的数字孪生体和模型 ID,请执行以下命令:

DigitalTwinClient digitalTwinClient = DigitalTwinClient.CreateFromConnectionString(parameters.HubConnectionString);
HttpOperationResponse<ThermostatTwin, DigitalTwinGetHeaders> getDigitalTwinResponse = await digitalTwinClient
    .GetDigitalTwinAsync<ThermostatTwin>(digitalTwinId);
ThermostatTwin thermostatTwin = getDigitalTwinResponse.Body;
Console.WriteLine($"Model ID: {thermostatTwin.Metadata.ModelId}.");
Console.WriteLine($"Digital Twin: \n{JsonConvert.SerializeObject(thermostatTwin, Formatting.Indented)}");

更新数字孪生体

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 在设备的默认组件中定义该属性:

var updateOperation = new UpdateOperationsUtility();

int desiredTargetTemperature = 60;

// Get the current value of the targetTemperature property
HttpOperationResponse<ThermostatTwin, DigitalTwinGetHeaders> getDigitalTwinResponse = await digitalTwinClient
    .GetDigitalTwinAsync<ThermostatTwin>(digitalTwinId);
double? currentTargetTemperature = getDigitalTwinResponse.Body.TargetTemperature;

// Has the targetTemperature property previously been set?
if (currentTargetTemperature != null)
{
  // Update the existing property
  // Prepend the property path with a '/'
  updateOperation.AppendReplacePropertyOp($"/targetTemperature",   desiredTargetTemperature);
}
else
{
  // Add a new property
  // Prepend the property path with a '/'
  updateOperation.AppendAddPropertyOp($"/targetTemperature", desiredTargetTemperature);
}

// Update the targetTemperature property on the digital twin
HttpOperationHeaderResponse<DigitalTwinUpdateHeaders> updateDigitalTwinResponse = await digitalTwinClient
    .UpdateDigitalTwinAsync(digitalTwinId, updateOperation.Serialize());

Console.WriteLine($"Update {digitalTwinId} digital twin response: {updateDigitalTwinResponse.Response.StatusCode}.");

以下代码片段演示如何更新组件上的 targetTemperature 属性。 在 Thermostat1 组件中定义该属性:

int desiredTargetTemperature = 60;

var updateOperation = new UpdateOperationsUtility();

// Look at when the property was updated and what was it set to.
HttpOperationResponse<TemperatureControllerTwin, DigitalTwinGetHeaders> getDigitalTwinResponse = await digitalTwinClient
  .GetDigitalTwinAsync<TemperatureControllerTwin>(digitalTwinId);

ThermostatTwin thermostat1 = getDigitalTwinResponse.Body.Thermostat1;

if (thermostat1 != null)
{
  // Thermostat1 is present in the TemperatureController twin. You can add/replace the component-level property "targetTemperature"
  double? currentComponentTargetTemperature = getDigitalTwinResponse.Body.Thermostat1.TargetTemperature;
  if (currentComponentTargetTemperature != null)
  {
      DateTimeOffset targetTemperatureDesiredLastUpdateTime = getDigitalTwinResponse.Body.Thermostat1.Metadata.TargetTemperature.LastUpdateTime;

      // The property path to be replaced should be prepended with a '/'
      updateOperation.AppendReplacePropertyOp("/thermostat1/targetTemperature", desiredTargetTemperature);
  }
  else
  {
      // The property path to be added should be prepended with a '/'
      updateOperation.AppendAddPropertyOp("/thermostat1/targetTemperature", desiredTargetTemperature);
  }
}
else
{
    // Thermostat1 is not present in the TemperatureController twin. Add the component.
    var componentProperty = new Dictionary<string, object> { { "targetTemperature", desiredTargetTemperature }, { "$metadata", new object() } };

    // The property path to be replaced should be prepended with a '/'
    updateOperation.AppendAddComponentOp("/thermostat1", componentProperty);
}

HttpOperationHeaderResponse<DigitalTwinUpdateHeaders> updateDigitalTwinResponse = await digitalTwinClient
    .UpdateDigitalTwinAsync(digitalTwinId, updateOperation.Serialize());

Console.WriteLine($"Update {digitalTwinId} digital twin response: {updateDigitalTwinResponse.Response.StatusCode}.");

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

DateTimeOffset since = DateTimeOffset.Now.Subtract(TimeSpan.FromMinutes(2));

try
{
  HttpOperationResponse<DigitalTwinCommandResponse, DigitalTwinInvokeCommandHeaders> invokeCommandResponse = await digitalTwinClient
    .InvokeCommandAsync(digitalTwinId, "getMaxMinReport", JsonConvert.SerializeObject(since));

  Console.WriteLine($"Command getMaxMinReport was invoked. \nDevice returned status: {invokeCommandResponse.Body.Status}." +
    $"\nReport: {invokeCommandResponse.Body.Payload}");
}
catch (HttpOperationException e)
{
  if (e.Response.StatusCode == HttpStatusCode.NotFound)
  {
    Console.WriteLine($"Unable to execute command getMaxMinReport on {digitalTwinId}.");
  }
}

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 Thermostat1 组件中定义该命令:

DateTimeOffset since = DateTimeOffset.Now.Subtract(TimeSpan.FromMinutes(2));

try
{
    HttpOperationResponse<DigitalTwinCommandResponse, DigitalTwinInvokeCommandHeaders> invokeCommandResponse = await digitalTwinClient
        .InvokeComponentCommandAsync(digitalTwinId, "thermostat1", "getMaxMinReport", JsonConvert.SerializeObject(since));

    Console.WriteLine("Command getMaxMinReport was invoked on component thermostat1." +
        $"\nDevice returned status: {invokeCommandResponse.Body.Status}. \nReport: {invokeCommandResponse.Body.Payload}");
}
catch (HttpOperationException e)
{
    if (e.Response.StatusCode == HttpStatusCode.NotFound)
    {
        Console.WriteLine("Unable to execute command getMaxMinReport on component thermostat1.");
    }
}

读取设备遥测数据

IoT 即插即用设备将 DTDL 模型中定义的遥测数据发送到 IoT 中心。 默认情况下,IoT 中心会将遥测数据路由到一个可供你在其中使用遥测数据的事件中心终结点。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点

下面的代码片段演示如何从默认事件中心终结点读取遥测数据。 此代码片段中的代码取自 IoT 中心快速入门:将设备的遥测数据发送到 IoT 中心并使用后端应用程序进行读取

await using EventHubConsumerClient consumer = new EventHubConsumerClient(EventHubConsumerClient.DefaultConsumerGroupName, connectionString, EventHubName);

Console.WriteLine("Listening for messages on all partitions");

try
{
    await foreach (PartitionEvent partitionEvent in consumer.ReadEventsAsync(cancellationToken))
    {
        Console.WriteLine("Message received on partition {0}:", partitionEvent.Partition.PartitionId);

        string data = Encoding.UTF8.GetString(partitionEvent.Data.Body.ToArray());
        Console.WriteLine("\t{0}:", data);

        Console.WriteLine("Application properties (set by device):");
        foreach (var prop in partitionEvent.Data.Properties)
        {
            Console.WriteLine("\t{0}: {1}", prop.Key, prop.Value);
        }

        Console.WriteLine("System properties (set by IoT Hub):");
        foreach (var prop in partitionEvent.Data.SystemProperties)
        {
            Console.WriteLine("\t{0}: {1}", prop.Key, prop.Value);
        }
    }
}
catch (TaskCanceledException)
{
    // This is expected when the token is signaled; it should not be considered an
    // error in this scenario.
}

此前的代码的以下输出显示了由仅包含默认组件的无组件 Thermostat IoT 即插即用设备发送的温度遥测数据。 dt-dataschema 系统属性显示模型 ID:

Message received on partition 1:
        { "temperature": 25.5 }:
Application properties (set by device):
System properties (set by IoT Hub):
        iothub-connection-device-id: my-pnp-device
        iothub-connection-auth-method: {"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}
        iothub-connection-auth-generation-id: 637375045610235418
        iothub-enqueuedtime: 05/10/2020 14:30:58
        iothub-message-source: Telemetry
        dt-dataschema: dtmi:com:example:Thermostat;1
        content-type: application/json
        content-encoding: utf-8

此前的代码的以下输出显示了由多组件 TemperatureController IoT 即插即用设备发送的温度遥测数据。 dt-subject 系统属性显示发送了遥测数据的组件的名称。 此示例中的两个组件是 DTDL 模型中定义的 thermostat1thermostat2dt-dataschema 系统属性显示模型 ID:

Message received on partition 1:
        {"temperature":11.1}:
Application properties (set by device):
System properties (set by IoT Hub):
        dt-subject: thermostat1
        iothub-connection-device-id: my-pnp-device
        iothub-connection-auth-method: {"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}
        iothub-connection-auth-generation-id: 637375045610235418
        iothub-enqueuedtime: 05/10/2020 14:23:36
        iothub-message-source: Telemetry
        dt-dataschema: dtmi:com:example:TemperatureController;1
        content-type: application/json
        content-encoding: utf-8
Message received on partition 1:
        {"temperature":41.2}:
Application properties (set by device):
System properties (set by IoT Hub):
        dt-subject: thermostat2
        iothub-connection-device-id: my-pnp-device
        iothub-connection-auth-method: {"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}
        iothub-connection-auth-generation-id: 637375045610235418
        iothub-enqueuedtime: 05/10/2020 14:23:36
        iothub-message-source: Telemetry
        dt-dataschema: dtmi:com:example:TemperatureController;1
        content-type: application/json
        content-encoding: utf-8

读取设备孪生更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的设备孪生更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成设备孪生更改通知时,前面 C# 代码片段中显示的代码将生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Message received on partition 1:
        {"version":3,"properties":{"reported":{"maxTempSinceLastReboot":9.6,"$metadata":{"$lastUpdated":"2020-10-06T10:17:41.7408552Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-06T10:17:41.7408552Z"}},"$version":2}}}:
Application properties (set by device):
        hubName: my-pnp-hub
        deviceId: my-pnp-device
        operationTimestamp: 2020-10-06T10:17:41.7408552+00:00
        iothub-message-schema: twinChangeNotification
        opType: updateTwin
System properties (set by IoT Hub):
        iothub-connection-device-id: my-pnp-device
        iothub-enqueuedtime: 06/10/2020 10:17:41
        iothub-message-source: twinChangeEvents
        user-id: System.ArraySegment`1[System.Byte]
        correlation-id: 61394e8ba7d
        content-type: application/json
        content-encoding: utf-8

当 IoT 中心为包含组件的设备生成设备孪生更改通知时,前面 C# 代码片段中显示的代码将生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Message received on partition 1:
        {"version":5,"properties":{"reported":{"thermostat1":{"__t":"c","maxTempSinceLastReboot":9.6},"$metadata":{"$lastUpdated":"2020-10-06T10:27:59.515972Z","thermostat1":{"$lastUpdated":"2020-10-06T10:27:59.515972Z","__t":{"$lastUpdated":"2020-10-06T10:27:59.515972Z"},"maxTempSinceLastReboot":{"$lastUpdated":"2020-10-06T10:27:59.515972Z"}}},"$version":4}}}:
Application properties (set by device):
        hubName: my-pnp-hub
        deviceId: my-pnp-device
        operationTimestamp: 2020-10-06T10:27:59.5159720+00:00
        iothub-message-schema: twinChangeNotification
        opType: updateTwin
System properties (set by IoT Hub):
        iothub-connection-device-id: my-pnp-device
        iothub-enqueuedtime: 06/10/2020 10:27:59
        iothub-message-source: twinChangeEvents
        user-id: System.ArraySegment`1[System.Byte]
        correlation-id: 615051f364e
        content-type: application/json
        content-encoding: utf-8

读取数字孪生体更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的数字孪生体更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成数字孪生体更改通知时,此前的 C# 代码片段中显示的代码会生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Message received on partition 1:
        [{"op":"add","path":"/$metadata/maxTempSinceLastReboot","value":{"lastUpdateTime":"2020-10-06T10:39:16.0209836Z"}},{"op":"add","path":"/maxTempSinceLastReboot","value":34.9}]:
Application properties (set by device):
        hubName: my-pnp-hub
        deviceId: my-pnp-device
        operationTimestamp: 2020-10-06T10:39:16.0209836+00:00
        iothub-message-schema: digitalTwinChangeNotification
        opType: updateTwin
System properties (set by IoT Hub):
        iothub-connection-device-id: my-pnp-device
        iothub-enqueuedtime: 06/10/2020 10:39:16
        iothub-message-source: digitalTwinChangeEvents
        user-id: System.ArraySegment`1[System.Byte]
        correlation-id: 6169857bf8c
        content-type: application/json-patch+json
        content-encoding: utf-8

当 IoT 中心为包含组件的设备生成数字孪生体更改通知时,此前的 C# 代码片段中显示的代码会生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Message received on partition 1:
        [{"op":"add","path":"/thermostat1","value":{"$metadata":{"maxTempSinceLastReboot":{"lastUpdateTime":"2020-10-06T10:41:44.8312666Z"}},"maxTempSinceLastReboot":29.1}}]:
Application properties (set by device):
        hubName: my-pnp-hub
        deviceId: my-pnp-device
        operationTimestamp: 2020-10-06T10:41:44.8312666+00:00
        iothub-message-schema: digitalTwinChangeNotification
        opType: updateTwin
System properties (set by IoT Hub):
        iothub-connection-device-id: my-pnp-device
        iothub-enqueuedtime: 06/10/2020 10:41:44
        iothub-message-source: digitalTwinChangeEvents
        user-id: System.ArraySegment`1[System.Byte]
        correlation-id: 616f108f0e3
        content-type: application/json-patch+json
        content-encoding: utf-8

还可以使用以下资源:

IoT 中心服务客户端示例

本部分介绍了使用 IoT 中心服务客户端的 Java 示例以及来自 com.microsoft.azure.sdk.iot.service.devicetwin 命名空间的 DeviceTwin 和 DeviceMethod 类 。 使用 DeviceTwin 类通过设备孪生与设备状态交互。 还可以使用 DeviceTwin 类在 IoT 中心查询设备注册。 使用 DeviceMethod 类在设备上调用命令。 设备的 DTDL 模型定义了设备实现的属性和命令。 在代码片段中,deviceId 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取设备孪生和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的设备孪生和模型 ID,请执行以下命令:

DeviceTwin twinClient = DeviceTwin.createFromConnectionString(iotHubConnectionString);

// ...

DeviceTwinDevice twin = new DeviceTwinDevice(deviceId);
twinClient.getTwin(twin);
System.out.println("Model Id of this Twin is: " + twin.getModelId());

更新设备孪生

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 在更新之前,必须先获取孪生。 在设备的默认组件中定义该属性:

DeviceTwin twinClient = DeviceTwin.createFromConnectionString(iotHubConnectionString);
DeviceTwinDevice twin = new DeviceTwinDevice(deviceId);
twinClient.getTwin(twin);

double propertyValue = 60.2;
twin.setDesiredProperties(Collections.singleton(new Pair("targetTemperature", propertyValue)));
twinClient.updateTwin(twin);

以下代码片段演示如何更新组件上的 targetTemperature 属性。 在更新之前,必须先获取孪生。 在 thermostat1 组件中定义该属性:

public static Set<Pair> CreateComponentPropertyPatch(@NonNull String propertyName, @NonNull double propertyValue, @NonNull String componentName)
{
    JsonObject patchJson = new JsonObject();
    patchJson.addProperty("__t", "c");
    patchJson.addProperty(propertyName, propertyValue);
    return singleton(new Pair(componentName, patchJson));
}

// ...

DeviceTwin twinClient = DeviceTwin.createFromConnectionString(iotHubConnectionString);
DeviceTwinDevice twin = new DeviceTwinDevice(deviceId);
twinClient.getTwin(twin);

double propertyValue = 60.2;
twin.setDesiredProperties(CreateComponentPropertyPatch("targetTemperature", propertyValue, "thermostat1"));
twinClient.updateTwin(twin);

对于组件中的属性,属性补丁类似于以下示例:

{
  "thermostat1":
  {
    "__t": "c",
    "targetTemperature": 60.2
  }
}

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

DeviceMethod methodClient = DeviceMethod.createFromConnectionString(iotHubConnectionString);

Long responseTimeout = TimeUnit.SECONDS.toSeconds(200);
Long connectTimeout = TimeUnit.SECONDS.toSeconds(5);

String commandInput = ZonedDateTime.now(ZoneOffset.UTC).minusMinutes(5).format(DateTimeFormatter.ISO_DATE_TIME);
MethodResult result = methodClient.invoke(deviceId, "getMaxMinReport", responseTimeout, connectTimeout, commandInput);

System.out.println("Method result status is: " + result.getStatus());

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

DeviceMethod methodClient = DeviceMethod.createFromConnectionString(iotHubConnectionString);

Long responseTimeout = TimeUnit.SECONDS.toSeconds(200);
Long connectTimeout = TimeUnit.SECONDS.toSeconds(5);

String commandInput = ZonedDateTime.now(ZoneOffset.UTC).minusMinutes(5).format(DateTimeFormatter.ISO_DATE_TIME);
MethodResult result = methodClient.invoke(deviceId, "thermostat1*getMaxMinReport", responseTimeout, connectTimeout, commandInput);

System.out.println("Method result status is: " + result.getStatus());

IoT 中心数字孪生示例

你可以使用 com.microsoft.azure.sdk.iot.service.digitaltwin 命名空间中的 DigitalTwinAsyncClient 类来通过数字孪生与设备状态进行交互 。 以下示例还使用同一命名空间中的 UpdateOperationUtility 和 BasicDigitalTwin 类 。 设备的 DTDL 模型定义了设备实现的属性和命令。

digitalTwinid 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取数字孪生体和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的数字孪生体和模型 ID,请执行以下命令:

DigitalTwinAsyncClient asyncClient = DigitalTwinAsyncClient.createFromConnectionString(iotHubConnectionString);

CountDownLatch latch = new CountDownLatch(1);
asyncClient.getDigitalTwin(digitalTwinid, BasicDigitalTwin.class)
    .subscribe(
        getResponse ->
        {
            System.out.println("Digital Twin Model Id: " + getResponse.getMetadata().getModelId());
            System.out.println("Digital Twin: " + prettyBasicDigitalTwin(getResponse));
            latch.countDown();
        },
        error ->
        {
            System.out.println("Get Digital Twin failed: " + error);
            latch.countDown();
        });

latch.await(10, TimeUnit.SECONDS);

// ...

private static String prettyBasicDigitalTwin(BasicDigitalTwin basicDigitalTwin)
{
    Gson gson = new GsonBuilder().setPrettyPrinting().create();
    return gson.toJson(basicDigitalTwin);
}

更新数字孪生体

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 在设备的默认组件中定义该属性:

DigitalTwinAsyncClient asyncClient = DigitalTwinAsyncClient.createFromConnectionString(iotHubConnectionString);

CountDownLatch latch1 = new CountDownLatch(1);

UpdateOperationUtility updateOperationUtility = new UpdateOperationUtility();

// Add a new property.
updateOperationUtility.appendAddPropertyOperation("/" + "targetTemperature", 35);
asyncClient.updateDigitalTwin(digitalTwinid, updateOperationUtility.getUpdateOperations())
    .subscribe(
        getResponse ->
        {
            System.out.println("Updated Digital Twin");
            latch1.countDown();
        },
        error ->
        {
            System.out.println("Update Digital Twin failed: " + error);
            latch1.countDown();
        });
latch1.await(10, TimeUnit.SECONDS);
GetDigitalTwin();

// Replace an existing property.
CountDownLatch latch2 = new CountDownLatch(1);
updateOperationUtility.appendReplacePropertyOperation("/targetTemperature", 50);
asyncClient.updateDigitalTwin(digitalTwinid, updateOperationUtility.getUpdateOperations())
    .subscribe(
        getResponse ->
        {
            System.out.println("Updated Digital Twin");
            latch2.countDown();
        },
        error ->
        {
            System.out.println("Update Digital Twin failed: " + error);
            latch2.countDown();
        });

latch2.await(10, TimeUnit.SECONDS);
GetDigitalTwin();

以下代码片段演示如何更新组件上的 targetTemperature 属性。 在 thermostat1 组件中定义该属性:

DigitalTwinClient client = DigitalTwinClient.createFromConnectionString(iotHubConnectionString);

// Get digital twin.
ServiceResponseWithHeaders<String, DigitalTwinGetHeaders> getResponse = client.getDigitalTwinWithResponse(digitalTwinid, String.class);

// Construct the options for conditional update.
DigitalTwinUpdateRequestOptions options = new DigitalTwinUpdateRequestOptions();
options.setIfMatch(getResponse.headers().eTag());

UpdateOperationUtility updateOperationUtility = new UpdateOperationUtility();

Map<String, Object> t1properties = new HashMap<>();
t1properties.put("targetTemperature", 50);
updateOperationUtility.appendReplaceComponentOperation("/thermostat1", t1properties);

digitalTwinUpdateOperations = updateOperationUtility.getUpdateOperations();
updateResponse = client.updateDigitalTwinWithResponse(digitalTwinid, digitalTwinUpdateOperations, options);
System.out.println("Update Digital Twin response status: " + updateResponse.response().message());

getResponse = client.getDigitalTwinWithResponse(digitalTwinid, String.class);

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

CountDownLatch latch = new CountDownLatch(1);

String commandInput = ZonedDateTime.now(ZoneOffset.UTC).minusMinutes(5).format(DateTimeFormatter.ISO_DATE_TIME);

// Invoke a method on root level.
asyncClient.invokeCommand(digitalTwinid, "getMaxMinReport", commandInput)
    .subscribe(
        response ->
        {
            System.out.println("Invoked Command getMaxMinReport response: " + prettyString(response.getPayload()));
            latch.countDown();
        },
        error ->
        {
            RestException ex = (RestException)error;
            if(ex.response().code() == 404) {
                System.out.println("Invoked Command getMaxMinReport failed: " + error);
            }
            else {
                System.out.println("Ensure the device sample is running for this sample to succeed");
            }
            latch.countDown();
        });

latch.await(10, TimeUnit.SECONDS);

// ...

private static String prettyString(String str)
{
    Gson gson = new Gson();
    Gson gsonBuilder = new GsonBuilder().setPrettyPrinting().create();
    return gsonBuilder.toJson(gson.fromJson(str, Object.class));
}

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

DigitalTwinClient client = DigitalTwinClient.createFromConnectionString(iotHubConnectionString);

String commandInput = ZonedDateTime.now(ZoneOffset.UTC).minusMinutes(5).format(DateTimeFormatter.ISO_DATE_TIME);

DigitalTwinInvokeCommandRequestOptions options = new DigitalTwinInvokeCommandRequestOptions();
try {
    ServiceResponseWithHeaders<DigitalTwinCommandResponse, DigitalTwinInvokeCommandHeaders> commandResponse = client.invokeComponentCommandWithResponse(digitalTwinid, "thermostat1", "getMaxMinReport", commandInput, options);
    System.out.println("Command getMaxMinReport, payload: " + prettyString(commandResponse.body().getPayload()));
    System.out.println("Command getMaxMinReport, status: " + commandResponse.body().getStatus());
} catch (RestException ex)
{
    if(ex.response().code() == 404)
    {
        System.out.println("Ensure the device sample is running for this sample to succeed.");
    }
    else
    {
        throw ex;
    }
}

// ...

private static String prettyString(String str)
{
    Gson gson = new Gson();
    Gson gsonBuilder = new GsonBuilder().setPrettyPrinting().create();
    return gsonBuilder.toJson(gson.fromJson(str, Object.class));
}

读取设备遥测数据

IoT 即插即用设备将 DTDL 模型中定义的遥测数据发送到 IoT 中心。 默认情况下,IoT 中心会将遥测数据路由到一个可供你在其中使用遥测数据的事件中心终结点。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点

下面的代码片段演示如何从默认事件中心终结点读取遥测数据。 此代码片段中的代码取自 IoT 中心快速入门:将设备的遥测数据发送到 IoT 中心并使用后端应用程序进行读取

import com.azure.messaging.eventhubs.EventHubClientBuilder;
import com.azure.messaging.eventhubs.EventHubConsumerAsyncClient;

// ...

EventHubClientBuilder eventHubClientBuilder = new EventHubClientBuilder()
    .consumerGroup(EventHubClientBuilder.DEFAULT_CONSUMER_GROUP_NAME)
    .connectionString(eventHubCompatibleConnectionString);

try (EventHubConsumerAsyncClient eventHubConsumerAsyncClient = eventHubClientBuilder.buildAsyncConsumerClient()) {

    receiveFromAllPartitions(eventHubConsumerAsyncClient);

}

// ...

private static void receiveFromAllPartitions(EventHubConsumerAsyncClient eventHubConsumerAsyncClient) {

eventHubConsumerAsyncClient
    .receive(false) // set this to false to read only the newly available events
    .subscribe(partitionEvent -> {
        System.out.println();
        System.out.printf("%nTelemetry received from partition %s:%n%s",
            partitionEvent.getPartitionContext().getPartitionId(), partitionEvent.getData().getBodyAsString());
        System.out.printf("%nApplication properties (set by device):%n%s", partitionEvent.getData().getProperties());
        System.out.printf("%nSystem properties (set by IoT Hub):%n%s",
            partitionEvent.getData().getSystemProperties());
    }, ex -> {
        System.out.println("Error receiving events " + ex);
    }, () -> {
        System.out.println("Completed receiving events");
    });
}

此前的代码的以下输出显示了由仅包含默认组件的无组件 Thermostat IoT 即插即用设备发送的温度遥测数据。 dt-dataschema 系统属性显示模型 ID:

Telemetry received from partition 1:
{"temperature": 10.700000}
Application properties (set by device):
{$.cdid=my-pnp-device}
System properties (set by IoT Hub):
{correlation-id=dd960185-6ddb-4b5f-89bb-e26b0b3c201e, content-encoding=UTF-8, iothub-connection-auth-method={"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}, iothub-enqueuedtime=Tue Oct 20 12:28:10 BST 2020, dt-dataschema=dtmi:com:example:Thermostat;1, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, iothub-connection-auth-generation-id=637375776990653481, group-sequence=0, iothub-message-source=Telemetry, creation-time=0, message-id=1c05cece-070b-4e2e-b2e8-e263858594a3, content-type=application/json}

Telemetry received from partition 1:
{"temperature": 10.700000}
Application properties (set by device):
{$.cdid=my-pnp-device}
System properties (set by IoT Hub):
{correlation-id=d10a7350-43ef-4cf6-9db5-a4b08684cd9d, content-encoding=UTF-8, iothub-connection-auth-method={"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}, iothub-enqueuedtime=Tue Oct 20 12:28:15 BST 2020, dt-dataschema=dtmi:com:example:Thermostat;1, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, iothub-connection-auth-generation-id=637375776990653481, group-sequence=0, iothub-message-source=Telemetry, creation-time=0, message-id=d3a80af4-1246-41a0-a09a-582a12c17a00, content-type=application/json}

此前的代码的以下输出显示了由多组件 TemperatureController IoT 即插即用设备发送的温度遥测数据。 dt-subject 系统属性显示发送了遥测数据的组件的名称。 此示例中的两个组件是 DTDL 模型中定义的 thermostat1thermostat2dt-dataschema 系统属性显示模型 ID:

Telemetry received from partition 1:
null
Application properties (set by device):
{$.cdid=my-pnp-device}
System properties (set by IoT Hub):
{correlation-id=413002d0-2107-4c08-8f4a-995ae1f4047b, content-encoding=UTF-8, iothub-connection-auth-method={"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}, iothub-enqueuedtime=Tue Oct 20 12:31:14 BST 2020, dt-dataschema=dtmi:com:example:TemperatureController;1, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, iothub-connection-auth-generation-id=637387902591517456, group-sequence=0, iothub-message-source=Telemetry, creation-time=0, message-id=da8bd068-850e-43fb-862f-66080d5969e4, content-type=application/json, dt-subject=thermostat1}

Telemetry received from partition 1:
null
Application properties (set by device):
{$.cdid=my-pnp-device}
System properties (set by IoT Hub):
{correlation-id=2d9407e5-413f-4f8d-bd30-cd153e03c72f, content-encoding=UTF-8, iothub-connection-auth-method={"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}, iothub-enqueuedtime=Tue Oct 20 12:31:14 BST 2020, dt-dataschema=dtmi:com:example:TemperatureController;1, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, iothub-connection-auth-generation-id=637387902591517456, group-sequence=0, iothub-message-source=Telemetry, creation-time=0, message-id=ed419c4e-ef2c-4acf-8991-6245059c5fdc, content-type=application/json, dt-subject=thermostat2}

读取设备孪生更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的设备孪生更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成设备孪生更改通知时,前面 Java 代码片段中显示的代码将生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received from partition 1:
{"version":11,"properties":{"reported":{"maxTempSinceLastReboot":43.4,"$metadata":{"$lastUpdated":"2020-10-20T11:50:41.123127Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-20T11:50:41.123127Z"}},"$version":10}}}
Application properties (set by device):
{operationTimestamp=2020-10-20T11:50:41.1231270+00:00, opType=updateTwin, hubName=my-pnp-hub, deviceId=my-pnp-device, iothub-message-schema=twinChangeNotification}
System properties (set by IoT Hub):
{user-id=[B@12fd5bb4, correlation-id=11339418426a, content-encoding=utf-8, iothub-enqueuedtime=Tue Oct 20 12:50:41 BST 2020, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, group-sequence=0, iothub-message-source=twinChangeEvents, creation-time=0, content-type=application/json}

当 IoT 中心为包含组件的设备生成设备孪生更改通知时,前面 Java 代码片段中显示的代码将生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received from partition 1:
{"version":9,"properties":{"reported":{"thermostat1":{"__t":"c","maxTempSinceLastReboot":32.5},"$metadata":{"$lastUpdated":"2020-10-20T11:48:01.2960851Z","thermostat1":{"$lastUpdated":"2020-10-20T11:48:01.2960851Z","__t":{"$lastUpdated":"2020-10-20T11:48:01.2960851Z"},"maxTempSinceLastReboot":{"$lastUpdated":"2020-10-20T11:48:01.2960851Z"}}},"$version":8}}}
Application properties (set by device):
{operationTimestamp=2020-10-20T11:48:01.2960851+00:00, opType=updateTwin, hubName=my-pnp-hub, deviceId=my-pnp-device, iothub-message-schema=twinChangeNotification}
System properties (set by IoT Hub):
{user-id=[B@23949bae, correlation-id=113334d542e1, content-encoding=utf-8, iothub-enqueuedtime=Tue Oct 20 12:48:01 BST 2020, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, group-sequence=0, iothub-message-source=twinChangeEvents, creation-time=0, content-type=application/json}

读取数字孪生体更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的数字孪生体更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成数字孪生更改通知时,前面 Java 代码片段中显示的代码将生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received from partition 1:
[{"op":"replace","path":"/$metadata/maxTempSinceLastReboot/lastUpdateTime","value":"2020-10-20T11:52:40.627628Z"},{"op":"replace","path":"/maxTempSinceLastReboot","value":16.9}]
Application properties (set by device):
{operationTimestamp=2020-10-20T11:52:40.6276280+00:00, opType=updateTwin, hubName=my-pnp-hub, deviceId=my-pnp-device, iothub-message-schema=digitalTwinChangeNotification}
System properties (set by IoT Hub):
{user-id=[B@4475ce2a, correlation-id=1133db52c0e0, content-encoding=utf-8, iothub-enqueuedtime=Tue Oct 20 12:52:40 BST 2020, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, group-sequence=0, iothub-message-source=digitalTwinChangeEvents, creation-time=0, content-type=application/json-patch+json}

当 IoT 中心为包含组件的设备生成数字孪生更改通知时,前面 Java 代码片段中显示的代码将生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received from partition 1:
[{"op":"add","path":"/thermostat1","value":{"$metadata":{"maxTempSinceLastReboot":{"lastUpdateTime":"2020-10-20T11:31:04.7811405Z"}},"maxTempSinceLastReboot":27.2}}]
Application properties (set by device):
{operationTimestamp=2020-10-20T11:31:04.7811405+00:00, opType=updateTwin, hubName=my-pnp-hub, deviceId=my-pnp-device, iothub-message-schema=digitalTwinChangeNotification}
System properties (set by IoT Hub):
{user-id=[B@75981aa, correlation-id=1130d6f4d212, content-encoding=utf-8, iothub-enqueuedtime=Tue Oct 20 12:31:04 BST 2020, absolute-expiry-time=0, iothub-connection-device-id=my-pnp-device, group-sequence=0, iothub-message-source=digitalTwinChangeEvents, creation-time=0, content-type=application/json-patch+json}

还可以使用以下资源:

IoT 中心服务客户端示例

本部分介绍有关使用 IoT 中心服务客户端的 JavaScript 示例以及 Registry 类和 Client 类 。 使用 Registry 类通过设备孪生与设备状态交互。 还可以使用 Registry 类在 IoT 中心查询设备注册。 使用 Client 类在设备上调用命令。 设备的 DTDL 模型定义了设备实现的属性和命令。 在代码片段中,deviceId 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取设备孪生和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的设备孪生和模型 ID,请执行以下命令:

var Registry = require('azure-iothub').Registry;

// ...

var registry = Registry.fromConnectionString(connectionString);
registry.getTwin(deviceId, function(err, twin) {
  if (err) {
    console.error(err.message);
  } else {
    console.log('Model Id: ' + twin.modelId);
    console.log(JSON.stringify(twin, null, 2));
  }
}

更新设备孪生

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 此示例演示为何需要以及如何在更新孪生之前获取孪生。 在设备的默认组件中定义该属性:

var Registry = require('azure-iothub').Registry;
var registry = Registry.fromConnectionString(connectionString);

registry.getTwin(deviceId, function(err, twin) {
  if (err) {
    console.error(err.message);
  } else {
    var twinPatch = {
      properties: {
        desired: {
          targetTemperature: 42
        }
      }
    };
    twin.update(twinPatch, function(err, twin) {
      if (err) {
        console.error(err.message);
      } else {
        console.log(JSON.stringify(twin, null, 2));
      }
    }
  }
}

以下代码片段演示如何更新组件上的 targetTemperature 属性。 此示例演示为何需要以及如何在更新孪生之前获取孪生。 在 thermostat1 组件中定义该属性:

var Registry = require('azure-iothub').Registry;
var registry = Registry.fromConnectionString(connectionString);

registry.getTwin(deviceId, function(err, twin) {
  if (err) {
    console.error(err.message);
  } else {
    var twinPatch = {
      properties: {
        desired: {
          thermostat1:
          {
            __t: "c",
            targetTemperature: 45
          }
        }
      }
    };
    twin.update(twinPatch, function(err, twin) {
      if (err) {
        console.error(err.message);
      } else {
        console.log(JSON.stringify(twin, null, 2));
      }
    }
  }
}

对于组件中的属性,属性补丁类似于以下示例:

{
  "thermostat1":
  {
    "__t": "c",
    "targetTemperature": 20
  }
}

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

var Client = require('azure-iothub').Client;

// ...

var client = Client.fromConnectionString(connectionString);

var methodParams = {
  methodName: "getMaxMinReport",
  payload: new Date().getMinutes -2,
  responseTimeoutInSeconds: 15
};

client.invokeDeviceMethod(deviceId, methodParams, function (err, result) {
  if (err) {
    console.error('Failed to invoke method \'' + methodParams.methodName + '\': ' + err.message);
  } else {
    console.log(methodParams.methodName + ' on ' + deviceId + ':');
    console.log(JSON.stringify(result, null, 2));
  }
});

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

var Client = require('azure-iothub').Client;

// ...

var client = Client.fromConnectionString(connectionString);

var methodParams = {
  methodName: "thermostat1*getMaxMinReport",
  payload: new Date().getMinutes -2,
  responseTimeoutInSeconds: 15
};

client.invokeDeviceMethod(deviceId, methodParams, function (err, result) {
  if (err) {
    console.error('Failed to invoke method \'' + methodParams.methodName + '\': ' + err.message);
  } else {
    console.log(methodParams.methodName + ' on ' + deviceId + ':');
    console.log(JSON.stringify(result, null, 2));
  }
});

IoT 中心数字孪生体示例

使用 DigitalTwinClient 类通过数字孪生体与设备状态交互。 设备的 DTDL 模型定义了设备实现的属性和命令。

本部分演示有关使用数字孪生 API 的 JavaScript 示例。

digitalTwinId 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取数字孪生体和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的数字孪生体和模型 ID,请执行以下命令:

const IoTHubTokenCredentials = require('azure-iothub').IoTHubTokenCredentials;
const DigitalTwinClient = require('azure-iothub').DigitalTwinClient;
const { inspect } = require('util');

// ...

const credentials = new IoTHubTokenCredentials(connectionString);
const digitalTwinClient = new DigitalTwinClient(credentials);

const digitalTwin = await digitalTwinClient.getDigitalTwin(digitalTwinId);

console.log(inspect(digitalTwin));
console.log('Model Id: ' + inspect(digitalTwin.$metadata.$model));

更新数字孪生体

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 在设备的默认组件中定义该属性:

const IoTHubTokenCredentials = require('azure-iothub').IoTHubTokenCredentials;
const DigitalTwinClient = require('azure-iothub').DigitalTwinClient;

// ...

const credentials = new IoTHubTokenCredentials(connString);
const digitalTwinClient = new DigitalTwinClient(credentials);

const patch = [{
  op: 'add',
  path: '/targetTemperature',
  value: 42
}];
await digitalTwinClient.updateDigitalTwin(digitalTwinId, patch);

以下代码片段演示如何更新组件上的 targetTemperature 属性。 在 thermostat1 组件中定义该属性:

const IoTHubTokenCredentials = require('azure-iothub').IoTHubTokenCredentials;
const DigitalTwinClient = require('azure-iothub').DigitalTwinClient;

// ...

const credentials = new IoTHubTokenCredentials(connString);
const digitalTwinClient = new DigitalTwinClient(credentials);

const patch = [{
  op: 'add',
  path: '/thermostat1/targetTemperature',
  value: 42
}];
await digitalTwinClient.updateDigitalTwin(digitalTwinId, patch);

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

const IoTHubTokenCredentials = require('azure-iothub').IoTHubTokenCredentials;
const DigitalTwinClient = require('azure-iothub').DigitalTwinClient;
const { inspect } = require('util');

// ...

const commandPayload = new Date().getMinutes -2;

const credentials = new IoTHubTokenCredentials(connectionString);
const digitalTwinClient = new DigitalTwinClient(credentials);

const options = {
  connectTimeoutInSeconds: 30,
  responseTimeoutInSeconds: 40
};
const commandResponse = await digitalTwinClient.invokeCommand(digitalTwinId, "getMaxMinReport", commandPayload, options);

console.log(inspect(commandResponse));

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

const IoTHubTokenCredentials = require('azure-iothub').IoTHubTokenCredentials;
const DigitalTwinClient = require('azure-iothub').DigitalTwinClient;
const { inspect } = require('util');

// ...

const commandPayload = new Date().getMinutes -2;

const credentials = new IoTHubTokenCredentials(connectionString);
const digitalTwinClient = new DigitalTwinClient(credentials);

const options = {
  connectTimeoutInSeconds: 30,
  responseTimeoutInSeconds: 40
};
const commandResponse = await digitalTwinClient.invokeComponentCommand(digitalTwinId, "thermostat1", "getMaxMinReport", commandPayload, options);

console.log(inspect(commandResponse));

读取设备遥测数据

IoT 即插即用设备将 DTDL 模型中定义的遥测数据发送到 IoT 中心。 默认情况下,IoT 中心会将遥测数据路由到一个可供你在其中使用遥测数据的事件中心终结点。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点

下面的代码片段演示如何从默认事件中心终结点读取遥测数据。 此代码片段中的代码取自 IoT 中心快速入门:将设备的遥测数据发送到 IoT 中心并使用后端应用程序进行读取

const { EventHubConsumerClient } = require("@azure/event-hubs");

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

var printMessages = function (messages) {
  for (const message of messages) {
    console.log("Telemetry received: ");
    console.log(JSON.stringify(message.body));
    console.log("Properties (set by device): ");
    console.log(JSON.stringify(message.properties));
    console.log("System properties (set by IoT Hub): ");
    console.log(JSON.stringify(message.systemProperties));
    console.log("");
  }
};

// ...

const clientOptions = {};

const consumerClient = new EventHubConsumerClient("$Default", connectionString, clientOptions);

consumerClient.subscribe({
  processEvents: printMessages,
  processError: printError,
});

前面代码的以下输出显示了由多组件 TemperatureController IoT 即插即用设备发送的温度遥测数据。 dt-subject 系统属性显示发送了遥测数据的组件的名称。 此示例中的两个组件是 DTDL 模型中定义的 thermostat1thermostat2dt-dataschema 系统属性显示模型 ID:

Telemetry received:
{"temperature":68.77370855171125}
Properties (set by device):
undefined
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-connection-auth-method":"{\"scope\":\"device\",\"type\":\"sas\",\"issuer\":\"iothub\",\"acceptingIpFilterRule\":null}","iothub-connection-auth-generation-id":"637388034455888246","iothub-enqueuedtime":1603206669320,"iothub-message-source":"Telemetry","dt-subject":"thermostat1","dt-dataschema":"dtmi:com:example:TemperatureController;1","contentType":"application/json","contentEncoding":"utf-8"}

Telemetry received:
{"temperature":30.833394506549226}
Properties (set by device):
undefined
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-connection-auth-method":"{\"scope\":\"device\",\"type\":\"sas\",\"issuer\":\"iothub\",\"acceptingIpFilterRule\":null}","iothub-connection-auth-generation-id":"637388034455888246","iothub-enqueuedtime":1603206665835,"iothub-message-source":"Telemetry","dt-subject":"thermostat2","dt-dataschema":"dtmi:com:example:TemperatureController;1","contentType":"application/json","contentEncoding":"utf-8"}

读取设备孪生更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的设备孪生更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成设备孪生更改通知时,前面 JavaScript 代码片段中显示的代码将生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received:
{"version":4,"properties":{"reported":{"maxTempSinceLastReboot":42.1415152639582,"$metadata":{"$lastUpdated":"2020-10-21T10:01:40.1281138Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-21T10:01:40.1281138Z"}},"$version":3}}}
Properties (set by device):
{"hubName":"my-pnp-hub","deviceId":"my-pnp-device","operationTimestamp":"2020-10-21T10:01:40.1281138+00:00","iothub-message-schema":"twinChangeNotification","opType":"updateTwin"}
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-enqueuedtime":1603274500282,"iothub-message-source":"twinChangeEvents","userId":{"type":"Buffer","data":[109,121,45,112,110,112,45,104,117,98]},"correlationId":"11ed82d13f50","contentType":"application/json","contentEncoding":"utf-8"}

当 IoT 中心为包含组件的设备生成设备孪生更改通知时,前面 JavaScript 代码片段中显示的代码将生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received:
{"version":4,"properties":{"reported":{"thermostat1":{"maxTempSinceLastReboot":3.5592971602417913,"__t":"c"},"$metadata":{"$lastUpdated":"2020-10-21T10:07:51.8284866Z","thermostat1":{"$lastUpdated":"2020-10-21T10:07:51.8284866Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-21T10:07:51.8284866Z"},"__t":{"$lastUpdated":"2020-10-21T10:07:51.8284866Z"}}},"$version":3}}}
Properties (set by device):
{"hubName":"my-pnp-hub","deviceId":"my-pnp-device","operationTimestamp":"2020-10-21T10:07:51.8284866+00:00","iothub-message-schema":"twinChangeNotification","opType":"updateTwin"}
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-enqueuedtime":1603274871951,"iothub-message-source":"twinChangeEvents","userId":{"type":"Buffer","data":[109,121,45,112,110,112,45,104,117,98]},"correlationId":"11ee605b195f","contentType":"application/json","contentEncoding":"utf-8"}

读取数字孪生体更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的数字孪生体更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成数字孪生更改通知时,前面 JavaScript 代码片段中显示的代码将生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received:
[{"op":"add","path":"/$metadata/maxTempSinceLastReboot","value":{"lastUpdateTime":"2020-10-21T10:01:40.1281138Z"}},{"op":"add","path":"/maxTempSinceLastReboot","value":42.1415152639582}]
Properties (set by device):
{"hubName":"my-pnp-hub","deviceId":"my-pnp-device","operationTimestamp":"2020-10-21T10:01:40.1281138+00:00","iothub-message-schema":"digitalTwinChangeNotification","opType":"updateTwin"}
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-enqueuedtime":1603274500282,"iothub-message-source":"digitalTwinChangeEvents","userId":{"type":"Buffer","data":[109,121,45,112,110,112,45,104,117,98]},"correlationId":"11ed82d13f50","contentType":"application/json-patch+json","contentEncoding":"utf-8"}

当 IoT 中心为包含组件的设备生成数字孪生更改通知时,前面 JavaScript 代码片段中显示的代码将生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Telemetry received:
[{"op":"add","path":"/thermostat1","value":{"$metadata":{"maxTempSinceLastReboot":{"lastUpdateTime":"2020-10-21T10:07:51.8284866Z"}},"maxTempSinceLastReboot":3.5592971602417913}}]
Properties (set by device):
{"hubName":"my-pnp-hub","deviceId":"my-pnp-device","operationTimestamp":"2020-10-21T10:07:51.8284866+00:00","iothub-message-schema":"digitalTwinChangeNotification","opType":"updateTwin"}
System properties (set by IoT Hub):
{"iothub-connection-device-id":"my-pnp-device","iothub-enqueuedtime":1603274871951,"iothub-message-source":"digitalTwinChangeEvents","userId":{"type":"Buffer","data":[109,121,45,112,110,112,45,104,117,98]},"correlationId":"11ee605b195f","contentType":"application/json-patch+json","contentEncoding":"utf-8"}

还可以使用以下资源:

IoT 中心服务客户端示例

此部分介绍的 Python 示例使用 IoT 中心服务客户端以及 IoTHubRegistryManager 和 CloudToDeviceMethod 类 。 使用 IoTHubRegistryManager 类通过设备孪生与设备状态交互。 还可以使用 IoTHubRegistryManager 类在 IoT 中心查询设备注册。 使用 CloudToDeviceMethod 类在设备上调用命令。 设备的 DTDL 模型定义了设备实现的属性和命令。 在代码片段中,device_id 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取设备孪生和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的设备孪生和模型 ID,请执行以下命令:

from azure.iot.hub import IoTHubRegistryManager
from azure.iot.hub.models import Twin, TwinProperties

iothub_registry_manager = IoTHubRegistryManager(iothub_connection_str)

# ...

twin = iothub_registry_manager.get_twin(device_id)
print("The device twin is: ")
print("")
print(twin)
print("")

additional_props = twin.additional_properties
if "modelId" in additional_props:
    print("The Model ID for this device is:")
    print(additional_props["modelId"])
    print("")

更新设备孪生

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 此示例演示你需要如何在更新孪生体之前获取其 etag。 在设备的默认组件中定义该属性:

iothub_registry_manager = IoTHubRegistryManager(iothub_connection_str)

twin = iothub_registry_manager.get_twin(device_id)

twin_patch = Twin()

twin_patch.properties = TwinProperties(
    desired={"targetTemperature": 42}
)
updated_twin = iothub_registry_manager.update_twin(device_id, twin_patch, twin.etag)

以下代码片段演示如何更新组件上的 targetTemperature 属性。 此示例演示你需要如何在更新孪生体之前获取其 ETag。 在 thermostat1 组件中定义该属性:

iothub_registry_manager = IoTHubRegistryManager(iothub_connection_str)

twin = iothub_registry_manager.get_twin(device_id)

twin_patch = Twin()

twin_patch.properties = TwinProperties(
    desired={ "thermostat1": {
        "__t": "c",
        "targetTemperature": 42}
    }
)
updated_twin = iothub_registry_manager.update_twin(device_id, twin_patch, twin.etag)

对于组件中的属性,属性补丁类似于以下示例:

{
"thermostat1":
  {
    "__t": "c",
    "targetTemperature": 20
  }
}

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

from azure.iot.hub import IoTHubRegistryManager
from azure.iot.hub.models import CloudToDeviceMethod

# ...

iothub_registry_manager = IoTHubRegistryManager(iothub_connection_str)

method_payload = datetime.datetime.now() - datetime.timedelta(minutes=2)
device_method = CloudToDeviceMethod(method_name="getMaxMinReport", payload=method_payload)
result = iothub_registry_manager.invoke_device_method(device_id, device_method)
print(result.payload)

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

from azure.iot.hub import IoTHubRegistryManager
from azure.iot.hub.models import CloudToDeviceMethod

# ...

iothub_registry_manager = IoTHubRegistryManager(iothub_connection_str)

method_payload = datetime.datetime.now() - datetime.timedelta(minutes=2)
device_method = CloudToDeviceMethod(method_name="thermostat1*getMaxMinReport", payload=method_payload)
result = iothub_registry_manager.invoke_device_method(device_id, device_method)
print(result.payload)

IoT 中心数字孪生体示例

使用 DigitalTwinClient 类通过数字孪生体与设备状态交互。 设备的 DTDL 模型定义了设备实现的属性和命令。

device_id 变量保存注册到 IoT 中心的 IoT 即插即用设备的设备 ID。

获取数字孪生体和模型 ID

若要获取连接到 IoT 中心的 IoT 即插即用设备的数字孪生体和模型 ID,请执行以下命令:

from azure.iot.hub import DigitalTwinClient

digital_twin_client = DigitalTwinClient(iothub_connection_str)

digital_twin = digital_twin_client.get_digital_twin(device_id)
if digital_twin:
    print(digital_twin)
    print("Model Id: " + digital_twin["$metadata"]["$model"])
else:
    print("No digital_twin found")

更新数字孪生体

下面的代码片段展示如何更新设备上的 targetTemperature 属性。 在设备的默认组件中定义该属性:

from azure.iot.hub import DigitalTwinClient

digital_twin_client = DigitalTwinClient(iothub_connection_str)

patch = [{"op": "add", "path": "/targetTemperature", "value": 42}]
digital_twin_client.update_digital_twin(device_id, patch)

以下代码片段演示如何更新组件上的 targetTemperature 属性。 在 thermostat1 组件中定义该属性:

from azure.iot.hub import DigitalTwinClient

digital_twin_client = DigitalTwinClient(iothub_connection_str)

patch = [{"op": "add", "path": "/targetTemperature", "value": 42}]
digital_twin_client.update_digital_twin(device_id, patch)

调用命令

以下代码片段演示如何调用默认组件中定义的 getMaxMinReport 命令:

from azure.iot.hub import DigitalTwinClient

payload = datetime.datetime.now() - datetime.timedelta(minutes=2)

connect_timeout_in_seconds = 3
response_timeout_in_seconds = 7


digital_twin_client = DigitalTwinClient(iothub_connection_str)

invoke_command_result = digital_twin_client.invoke_command(
    device_id, "getMaxMinReport", payload, connect_timeout_in_seconds, response_timeout_in_seconds
)
if invoke_command_result:
    print(invoke_command_result)
else:
    print("No invoke_command_result found")

以下代码片段演示如何在组件上调用 getMaxMinReport 命令。 在 thermostat1 组件中定义该命令:

from azure.iot.hub import DigitalTwinClient

payload = datetime.datetime.now() - datetime.timedelta(minutes=2)

connect_timeout_in_seconds = 3
response_timeout_in_seconds = 7


digital_twin_client = DigitalTwinClient(iothub_connection_str)

invoke_command_result = digital_twin_client.invoke_component_command(
    device_id, "thermostat1", "getMaxMinReport", payload, connect_timeout_in_seconds, response_timeout_in_seconds
)
if invoke_command_result:
    print(invoke_command_result)
else:
    print("No invoke_command_result found")

读取设备遥测数据

IoT 即插即用设备将 DTDL 模型中定义的遥测数据发送到 IoT 中心。 默认情况下,IoT 中心会将遥测数据路由到一个可供你在其中使用遥测数据的事件中心终结点。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点

下面的代码片段演示如何从默认事件中心终结点读取遥测数据。 此代码片段中的代码取自 IoT 中心快速入门:将设备的遥测数据发送到 IoT 中心并使用后端应用程序进行读取

import asyncio
from azure.eventhub import TransportType
from azure.eventhub.aio import EventHubConsumerClient

# Define callbacks to process events
async def on_event_batch(partition_context, events):
    for event in events:
        print("Received event from partition: {}.".format(partition_context.partition_id))
        print("Telemetry received: ", event.body_as_str())
        print("Properties (set by device): ", event.properties)
        print("System properties (set by IoT Hub): ", event.system_properties)
        print()
    await partition_context.update_checkpoint()

async def on_error(partition_context, error):
    # ...

loop = asyncio.get_event_loop()
client = EventHubConsumerClient.from_connection_string(
    conn_str=CONNECTION_STR,
    consumer_group="$default",
)

try:
    loop.run_until_complete(client.receive_batch(on_event_batch=on_event_batch, on_error=on_error))
except KeyboardInterrupt:
    print("Receiving has stopped.")
finally:
    loop.run_until_complete(client.close())
    loop.stop()

此前的代码的以下输出显示了由仅包含默认组件的无组件 Thermostat IoT 即插即用设备发送的温度遥测数据。 dt-dataschema 系统属性显示模型 ID:

Received event from partition: 1.
Telemetry received:  {"temperature": 12}
Properties (set by device):  None
System properties (set by IoT Hub):  {b'content-type': b'application/json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-connection-auth-method': b'{"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}', b'iothub-connection-auth-generation-id': b'637388855582764406', b'iothub-enqueuedtime': 1603288810715, b'iothub-message-source': b'Telemetry', b'dt-dataschema': b'dtmi:com:example:Thermostat;1', b'x-opt-sequence-number': 13280, b'x-opt-offset': b'12890070640', b'x-opt-enqueued-time': 1603288810824}

此前的代码的以下输出显示了由多组件 TemperatureController IoT 即插即用设备发送的温度遥测数据。 dt-subject 系统属性显示发送了遥测数据的组件的名称。 此示例中的两个组件是 DTDL 模型中定义的 thermostat1thermostat2dt-dataschema 系统属性显示模型 ID:

Received event from partition: 1.
Telemetry received:  {"temperature": 45}
Properties (set by device):  None
System properties (set by IoT Hub):  {b'content-type': b'application/json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-connection-auth-method': b'{"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}', b'iothub-connection-auth-generation-id': b'637388858939631652', b'iothub-enqueuedtime': 1603289127844, b'iothub-message-source': b'Telemetry', b'dt-subject': b'thermostat1', b'dt-dataschema': b'dtmi:com:example:TemperatureController;1', b'x-opt-sequence-number': 13328, b'x-opt-offset': b'12890095440', b'x-opt-enqueued-time': 1603289128001}

Received event from partition: 1.
Telemetry received:  {"temperature": 49}
Properties (set by device):  None
System properties (set by IoT Hub):  {b'content-type': b'application/json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-connection-auth-method': b'{"scope":"device","type":"sas","issuer":"iothub","acceptingIpFilterRule":null}', b'iothub-connection-auth-generation-id': b'637388858939631652', b'iothub-enqueuedtime': 1603289133017, b'iothub-message-source': b'Telemetry', b'dt-subject': b'thermostat2', b'dt-dataschema': b'dtmi:com:example:TemperatureController;1', b'x-opt-sequence-number': 13329, b'x-opt-offset': b'12890095928', b'x-opt-enqueued-time': 1603289133173}

读取设备孪生更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的设备孪生更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成设备孪生更改通知时,此前的 Python 代码片段中显示的代码会生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Received event from partition: 1.
Telemetry received:  {"version":3,"properties":{"reported":{"maxTempSinceLastReboot":10.96,"$metadata":{"$lastUpdated":"2020-10-21T14:10:42.4171263Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-21T14:10:42.4171263Z"}},"$version":2}}}
Properties (set by device):  {b'hubName': b'my-pnp-hub', b'deviceId': b'my-pnp-device', b'operationTimestamp': b'2020-10-21T14:10:42.4171263+00:00', b'iothub-message-schema': b'twinChangeNotification', b'opType': b'updateTwin'}
System properties (set by IoT Hub):  {b'user-id': b'my-pnp-hub\x81\x0e\xa4\x7f', b'correlation-id': b'12104ced5402', b'content-type': b'application/json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-enqueuedtime': 1603289442519, b'iothub-message-source': b'twinChangeEvents', b'x-opt-sequence-number': 13332, b'x-opt-offset': b'12890097392', b'x-opt-enqueued-time': 1603289442738}

当 IoT 中心为包含组件的设备生成设备孪生更改通知时,此前的 Python 代码片段中显示的代码会生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Received event from partition: 1.
Telemetry received:  {"version":4,"properties":{"reported":{"thermostat1":{"maxTempSinceLastReboot":98.34,"__t":"c"},"$metadata":{"$lastUpdated":"2020-10-21T14:13:39.36491Z","thermostat1":{"$lastUpdated":"2020-10-21T14:13:39.36491Z","maxTempSinceLastReboot":{"$lastUpdated":"2020-10-21T14:13:39.36491Z"},"__t":{"$lastUpdated":"2020-10-21T14:13:39.36491Z"}}},"$version":3}}}
Properties (set by device):  {b'hubName': b'my-pnp-hub', b'deviceId': b'my-pnp-device', b'operationTimestamp': b'2020-10-21T14:13:39.3649100+00:00', b'iothub-message-schema': b'twinChangeNotification', b'opType': b'updateTwin'}
System properties (set by IoT Hub):  {b'user-id': b'my-pnp-hub', b'correlation-id': b'1210b664ab83', b'content-type': b'application/json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-enqueuedtime': 1603289619481, b'iothub-message-source': b'twinChangeEvents', b'x-opt-sequence-number': 13341, b'x-opt-offset': b'12890102216', b'x-opt-enqueued-time': 1603289619668}

读取数字孪生体更改通知

可以配置 IoT 中心,以便生成要路由到支持的终结点的数字孪生体更改通知。 若要了解详细信息,请参阅使用 IoT 中心消息路由将设备到云的消息发送到不同的终结点 > 非遥测事件

当 IoT 中心为无组件恒温器设备生成数字孪生体更改通知时,此前的 Python 代码片段中显示的代码会生成以下输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Received event from partition: 1.
Telemetry received:  [{"op":"add","path":"/$metadata/maxTempSinceLastReboot","value":{"lastUpdateTime":"2020-10-21T14:10:42.4171263Z"}},{"op":"add","path":"/maxTempSinceLastReboot","value":10.96}]
Properties (set by device):  {b'hubName': b'my-pnp-hub', b'deviceId': b'my-pnp-device', b'operationTimestamp': b'2020-10-21T14:10:42.4171263+00:00', b'iothub-message-schema': b'digitalTwinChangeNotification', b'opType': b'updateTwin'}
System properties (set by IoT Hub):  {b'user-id': b'my-pnp-hub\x81\x0e\xa4\x7f', b'correlation-id': b'12104ced5402', b'content-type': b'application/json-patch+json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-enqueuedtime': 1603289442519, b'iothub-message-source': b'digitalTwinChangeEvents', b'x-opt-sequence-number': 13333, b'x-opt-offset': b'12890098024', b'x-opt-enqueued-time': 1603289442738}

当 IoT 中心为包含组件的设备生成数字孪生体更改通知时,此前的 Python 代码片段中显示的代码会生成以下输出。 此示例显示当具有恒温器组件的温度传感器设备生成通知时所生成的输出。 应用程序属性 iothub-message-schemaopType 提供有关更改通知类型的信息:

Received event from partition: 1.
Telemetry received:  [{"op":"add","path":"/thermostat1","value":{"$metadata":{"maxTempSinceLastReboot":{"lastUpdateTime":"2020-10-21T14:13:39.36491Z"}},"maxTempSinceLastReboot":98.34}}]
Properties (set by device):  {b'hubName': b'my-pnp-hub', b'deviceId': b'my-pnp-device', b'operationTimestamp': b'2020-10-21T14:13:39.3649100+00:00', b'iothub-message-schema': b'digitalTwinChangeNotification', b'opType': b'updateTwin'}
System properties (set by IoT Hub):  {b'user-id': b'my-pnp-hub', b'correlation-id': b'1210b664ab83', b'content-type': b'application/json-patch+json', b'content-encoding': b'utf-8', b'iothub-connection-device-id': b'my-pnp-device', b'iothub-enqueuedtime': 1603289619481, b'iothub-message-source': b'digitalTwinChangeEvents', b'x-opt-sequence-number': 13342, b'x-opt-offset': b'12890102984', b'x-opt-enqueued-time': 1603289619668}

后续步骤

现在,你已了解设备建模,以下是一些其他资源: