IoT 隨插即用服務開發人員指南

發行項
05/30/2024

IoT 隨插即用可讓您建立 IoT 裝置以向 Azure IoT 應用程式公告功能。當客戶將 IoT 隨插即用裝置連線到支援 IoT 隨插即用的應用程式時，不需手動設定這種裝置。

IoT 隨插即用可讓您使用已向 IoT 中樞宣告模型識別碼的裝置。例如，您可以直接存取裝置的屬性和命令。

如果您使用 IoT Central，您可以使用 IoT Central UI 和 REST API 來與連線至應用程式的 IoT 隨插即用裝置互動。

服務 SDK

在解決方案中使用 Azure IoT 服務 SDK，以便與裝置和模組互動。例如，您可以使用服務 SDK 來讀取和更新對應項屬性，並叫用命令。支援的語言包括 C#、JAVA、Node.js 和 Python。

Microsoft Azure IoT 服務 SDK 包含可協助建置應用程式的程式碼，這些應用程式可直接與「IoT 中樞」互動來管理裝置和安全性。

平台	套件	程式碼存放庫	範例	參考
.NET	NuGet (英文)	GitHub	範例	參考
Java	Maven	GitHub	範例	參考
節點	npm \(英文\)	GitHub	範例	參考
Python	pip	GitHub	範例	參考

服務 SDK 可讓您從解決方案元件存取裝置資訊，例如桌面應用程式或 Web 應用程式。服務 SDK 包含兩個命名空間和物件模型，可用來擷取模型識別碼：

IoT 中樞服務用戶端。此服務將模型識別碼公開為裝置對應項屬性。
Digital Twins 用戶端。新的 Digital Twins API 可處理數位對應項定義語言 (DTDL) 模型建構，例如元件、屬性和命令。 Digital Twin API 可讓解決方案建置者更輕鬆建立 IoT 隨插即用解決方案。

以下是可以使用的資源：

IoT 中樞服務用戶端範例

本節以 C# 範例示範使用 IoT 中樞服務用戶端及 RegistryManager 和 ServiceClient 類別。您使用 RegistryManager 類別來透過裝置對應項，與裝置狀態互動。您也可以使用 RegistryManager 類別在 IoT 中樞查詢裝置註冊。您使用 ServiceClient 類別在裝置上呼叫命令。裝置的 DTDL 模型定義裝置所實作的屬性和命令。在程式碼片段中，deviceTwinId 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得裝置對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其裝置對應項和模型識別碼：

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}.");

更新裝置對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得其 ETag。裝置的預設元件中定義此屬性：

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);

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得其 ETag。 Thermostat1 元件中定義此屬性：

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;
}

對於元件中的屬性，屬性修飾如下列範例所示：

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

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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}.";
}

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 Thermostat1 元件中定義此命令：

// 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 中樞數位對應項範例

您使用 DigitalTwinClient 類別來透過數位對應項，與裝置狀態互動。裝置的 DTDL 模型定義裝置所實作的屬性和命令。

本節以 C# 範例示範使用 Digital Twins API。下列程式碼片段使用下列類別來代表控溫器和溫度控制器裝置的數位對應項：

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 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得數位對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其數位對應項和模型識別碼：

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)}");

更新數位對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。裝置的預設元件中定義此屬性：

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}.");

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。 Thermostat1 元件中定義此屬性：

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}.");

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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}.");
  }
}

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 Thermostat1 元件中定義此命令：

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.");
    }
}

讀取裝置遙測

IoT 隨插即用裝置會將 DTDL 模型中定義的遙測傳送至 IoT 中樞。 IoT 中樞預設將遙測路由傳送至事件中樞端點供您取用。若要深入了解，請參閱使用 IoT 中樞訊息路由將裝置到雲端的訊息傳送至不同的端點。

下列程式碼片段示範如何從預設事件中樞端點讀取遙測。此程式碼片段中的程式碼取自 IoT 中樞快速入門：將遙測從裝置傳送至 IoT 中樞，並使用後端應用程式讀取遙測：

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.
}

上方程式碼的輸出如下，顯示只具有預設元件的無元件 Thermostat IoT 隨插即用裝置所傳送的溫度遙測。 dt-dataschema 系統屬性顯示模型識別碼：

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

上方程式碼的輸出如下，顯示多元件 TemperatureController IoT 隨插即用裝置所傳送的溫度遙測。 dt-subject 系統屬性顯示傳送遙測的元件名稱。在此範例中，DTDL 模型中定義的兩個元件是 thermostat1 和 thermostat2。 dt-dataschema 系統屬性顯示模型識別碼：

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

讀取裝置對應項變更通知

您可以將 IoT 中樞設定為產生裝置對應項變更通知，以路由傳送至支援的端點。若要深入了解，請參閱使用 IoT 中樞訊息路由將裝置到雲端的訊息傳送至不同的端點 > 非遙測事件。

當 IoT 中樞為無元件控溫器裝置產生裝置對應項變更通知時，上一個 C# 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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

當 IoT 中樞為具有元件的裝置產生裝置對應項變更通知時，上一個 C# 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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

讀取數位對應項變更通知

您可以將 IoT 中樞設定為產生數位對應項變更通知，以路由傳送至支援的端點。若要深入了解，請參閱使用 IoT 中樞訊息路由將裝置到雲端的訊息傳送至不同的端點 > 非遙測事件。

當 IoT 中樞為無元件控溫器裝置產生數位對應項變更通知時，上一個 C# 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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

當 IoT 中樞為具有元件的裝置產生數位對應項變更通知時，上一個 C# 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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

以下是可以使用的資源：

IoT 中樞服務用戶端範例

本節以 JAVA 範例示範使用 IoT 中樞服務用戶端及 com.microsoft.azure.sdk.iot.service.devicetwin 命名空間中的 DeviceTwin 和 DeviceMethod 類別。您使用 DeviceTwin 類別來透過裝置對應項，與裝置狀態互動。您也可以使用 DeviceTwin 類別在 IoT 中樞查詢裝置註冊。您使用 DeviceMethod 類別在裝置上呼叫命令。裝置的 DTDL 模型定義裝置所實作的屬性和命令。在程式碼片段中，deviceId 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得裝置對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其裝置對應項和模型識別碼：

DeviceTwin twinClient = DeviceTwin.createFromConnectionString(iotHubConnectionString);

// ...

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

更新裝置對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。更新對應項之前，您必須先取得對應項。裝置的預設元件中定義此屬性：

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);

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。更新對應項之前，您必須先取得對應項。 thermostat1 元件中定義此屬性：

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);

對於元件中的屬性，屬性修飾如下列範例所示：

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

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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());

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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 中樞數位對應項範例

您使用 com.microsoft.azure.sdk.iot.service.digitaltwin 命名空間中的 DigitalTwinAsyncClient 類別來透過數位對應項，與裝置狀態互動。下列範例會使用同一個命名空間中的 UpdateOperationUtility 和 BasicDigitalTwin 類別。裝置的 DTDL 模型定義裝置所實作的屬性和命令。

digitalTwinid 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得數位對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其數位對應項和模型識別碼：

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);
}

更新數位對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。裝置的預設元件中定義此屬性：

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();

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。 thermostat1 元件中定義此屬性：

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);

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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));
}

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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));
}

讀取裝置遙測

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");
    });
}

上方程式碼的輸出如下，顯示只具有預設元件的無元件 Thermostat IoT 隨插即用裝置所傳送的溫度遙測。 dt-dataschema 系統屬性顯示模型識別碼：

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=aaaa0000-bb11-2222-33cc-444444dddddd, 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=aaaabbbb-0000-cccc-1111-dddd2222eeee, 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=bbbb1111-cc22-3333-44dd-555555eeeeee, 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=bbbbcccc-1111-dddd-2222-eeee3333ffff, content-type=application/json}

Telemetry received from partition 1:
null
Application properties (set by device):
{$.cdid=my-pnp-device}
System properties (set by IoT Hub):
{correlation-id=cccc2222-dd33-4444-55ee-666666ffffff, 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=ccccdddd-2222-eeee-3333-ffff4444aaaa, 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=dddd3333-ee44-5555-66ff-777777aaaaaa, 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=ddddeeee-3333-ffff-4444-aaaa5555bbbb, content-type=application/json, dt-subject=thermostat2}

讀取裝置對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生裝置對應項變更通知時，上一個 JAVA 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

當 IoT 中樞為具有元件的裝置產生裝置對應項變更通知時，上一個 JAVA 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

讀取數位對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生數位對應項變更通知時，上一個 JAVA 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

當 IoT 中樞為具有元件的裝置產生數位對應項變更通知時，上一個 JAVA 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

以下是可以使用的資源：

IoT 中樞服務用戶端範例

本節以 JavaScript 範例示範使用 IoT 中樞服務用戶端及 Registry 和 Client 類別。您使用 Registry 類別來透過裝置對應項，與裝置狀態互動。您也可以使用 Registry 類別在 IoT 中樞查詢裝置註冊。您使用 Client 類別在裝置上呼叫命令。裝置的 DTDL 模型定義裝置所實作的屬性和命令。在程式碼片段中，deviceId 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得裝置對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其裝置對應項和模型識別碼：

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));
  }
}

更新裝置對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得對應項。裝置的預設元件中定義此屬性：

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));
      }
    }
  }
}

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得對應項。 thermostat1 元件中定義此屬性：

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));
      }
    }
  }
}

對於元件中的屬性，屬性修飾如下列範例所示：

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

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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));
  }
});

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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 中樞數位對應項範例

您使用 DigitalTwinClient 類別來透過數位對應項，與裝置狀態互動。裝置的 DTDL 模型定義裝置所實作的屬性和命令。

本節以 JavaScript 範例示範使用 Digital Twins API。

digitalTwinId 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得數位對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其數位對應項和模型識別碼：

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));

更新數位對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。裝置的預設元件中定義此屬性：

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);

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。 thermostat1 元件中定義此屬性：

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);

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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));

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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));

讀取裝置遙測

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,
});

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"}

讀取裝置對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生裝置對應項變更通知時，上一個 JavaScript 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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"}

當 IoT 中樞為具有元件的裝置產生裝置對應項變更通知時，上一個 JavaScript 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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"}

讀取數位對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生數位對應項變更通知時，上一個 JavaScript 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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"}

當 IoT 中樞為具有元件的裝置產生數位對應項變更通知時，上一個 JavaScript 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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"}

以下是可以使用的資源：

IoT 中樞服務用戶端範例

本節以 Python 範例示範使用 IoT 中樞服務用戶端及 IoTHubRegistryManager 和 CloudToDeviceMethod 類別。您使用 IoTHubRegistryManager 類別來透過裝置對應項，與裝置狀態互動。您也可以使用 IoTHubRegistryManager 類別在 IoT 中樞查詢裝置註冊。您使用 CloudToDeviceMethod 類別在裝置上呼叫命令。裝置的 DTDL 模型定義裝置所實作的屬性和命令。在程式碼片段中，device_id 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得裝置對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其裝置對應項和模型識別碼：

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("")

更新裝置對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得其 etag。裝置的預設元件中定義此屬性：

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)

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。此範例示範在更新對應項之前需要如何取得其 ETag。 thermostat1 元件中定義此屬性：

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)

對於元件中的屬性，屬性修飾如下列範例所示：

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

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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)

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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 中樞數位對應項範例

您使用 DigitalTwinClient 類別來透過數位對應項，與裝置狀態互動。裝置的 DTDL 模型定義裝置所實作的屬性和命令。

device_id 變數保留已向 IoT 中樞註冊的 IoT 隨插即用裝置的裝置識別碼。

取得數位對應項和模型識別碼

對於連線到 IoT 中樞的 IoT 隨插即用裝置，若要取得其數位對應項和模型識別碼：

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")

更新數位對應項

下列程式碼片段示範如何更新裝置上的 targetTemperature 屬性。裝置的預設元件中定義此屬性：

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)

下列程式碼片段示範如何更新元件上的 targetTemperature 屬性。 thermostat1 元件中定義此屬性：

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)

呼叫命令

下列程式碼片段示範如何叫用預設元件中定義的 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")

下列程式碼片段示範如何在元件上呼叫 getMaxMinReport 命令。 thermostat1 元件中定義此命令：

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")

讀取裝置遙測

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()

上方程式碼的輸出如下，顯示只具有預設元件的無元件 Thermostat IoT 隨插即用裝置所傳送的溫度遙測。 dt-dataschema 系統屬性顯示模型識別碼：

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}

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}

讀取裝置對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生裝置對應項變更通知時，上一個 Python 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

當 IoT 中樞為具有元件的裝置產生裝置對應項變更通知時，上一個 Python 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

讀取數位對應項變更通知

當 IoT 中樞為無元件控溫器裝置產生數位對應項變更通知時，上一個 Python 程式碼片段中顯示的程式碼會產生下列輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

當 IoT 中樞為具有元件的裝置產生數位對應項變更通知時，上一個 Python 程式碼片段中顯示的程式碼會產生下列輸出。此範例顯示具有控溫器元件的溫度感應器裝置產生通知時的輸出。應用程式屬性 iothub-message-schema 和 opType 提供變更通知類型的相關資訊：

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}

下一步

現在您已了解裝置模型，以下有一些更多的資源可供參考：

共用方式為

IoT 隨插即用服務開發人員指南

服務 SDK

IoT 中樞服務用戶端範例

取得裝置對應項和模型識別碼

更新裝置對應項

呼叫命令

IoT 中樞數位對應項範例

取得數位對應項和模型識別碼

更新數位對應項

呼叫命令

讀取裝置遙測

讀取裝置對應項變更通知

讀取數位對應項變更通知

IoT 中樞服務用戶端範例

取得裝置對應項和模型識別碼

更新裝置對應項

呼叫命令

IoT 中樞數位對應項範例

取得數位對應項和模型識別碼

更新數位對應項

呼叫命令

讀取裝置遙測

讀取裝置對應項變更通知

讀取數位對應項變更通知

IoT 中樞服務用戶端範例

取得裝置對應項和模型識別碼

更新裝置對應項

呼叫命令

IoT 中樞數位對應項範例

取得數位對應項和模型識別碼

更新數位對應項

呼叫命令

讀取裝置遙測

讀取裝置對應項變更通知

讀取數位對應項變更通知

IoT 中樞服務用戶端範例

取得裝置對應項和模型識別碼

更新裝置對應項

呼叫命令

IoT 中樞數位對應項範例

取得數位對應項和模型識別碼

更新數位對應項

呼叫命令

讀取裝置遙測

讀取裝置對應項變更通知

讀取數位對應項變更通知

下一步

意見反應

其他資源