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IoT 即插即用设备开发人员指南

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。

IoT 设备可以直接实现,也可以使用模块IoT Edge 模块

本指南介绍了创建遵循 IoT 即插即用约定的设备、模块或 IoT Edge 模块所需的基本步骤。

若要生成 IoT 即插即用设备、模块或 IoT Edge 模块,请按以下步骤操作:

  1. 确保你的设备使用 MQTT 或 MQTT over WebSockets 协议连接到 Azure IoT 中心。
  2. 创建数字孪生定义语言 (DTDL) 模型来描述你的设备。 若要了解详细信息,请参阅了解 IoT 即插即用模型中的组件
  3. 更新设备或模块,以宣布 model-id 作为设备连接的一部分。
  4. 遵循 IoT 即插即用约定实现遥测、属性和命令

在设备或模块实现就绪后,使用 Azure IoT 资源管理器来验证设备是否遵循 IoT 即插即用约定。

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

static const char g_ThermostatModelId[] = "dtmi:com:example:Thermostat;1";
IOTHUB_DEVICE_CLIENT_LL_HANDLE deviceHandle = NULL;
deviceHandle = CreateDeviceClientLLHandle();
iothubResult = IoTHubDeviceClient_LL_SetOption(
    deviceHandle, OPTION_MODEL_ID, g_ThermostatModelId);

提示

对于模块和 IoT Edge,使用 IoTHubModuleClient_LL 代替 IoTHubDeviceClient_LL

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则:

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性:

void PnP_ThermostatComponent_SendTelemetry(
    PNP_THERMOSTAT_COMPONENT_HANDLE pnpThermostatComponentHandle,
    IOTHUB_DEVICE_CLIENT_LL_HANDLE deviceClientLL)
{
    PNP_THERMOSTAT_COMPONENT* pnpThermostatComponent = (PNP_THERMOSTAT_COMPONENT*)pnpThermostatComponentHandle;
    IOTHUB_MESSAGE_HANDLE messageHandle = NULL;
    IOTHUB_CLIENT_RESULT iothubResult;

    char temperatureStringBuffer[32];

    if (snprintf(
        temperatureStringBuffer,
        sizeof(temperatureStringBuffer),
        g_temperatureTelemetryBodyFormat,
        pnpThermostatComponent->currentTemperature) < 0)
    {
        LogError("snprintf of current temperature telemetry failed");
    }
    else if ((messageHandle = PnP_CreateTelemetryMessageHandle(
        pnpThermostatComponent->componentName, temperatureStringBuffer)) == NULL)
    {
        LogError("Unable to create telemetry message");
    }
    else if ((iothubResult = IoTHubDeviceClient_LL_SendEventAsync(
        deviceClientLL, messageHandle, NULL, NULL)) != IOTHUB_CLIENT_OK)
    {
        LogError("Unable to send telemetry message, error=%d", iothubResult);
    }

    IoTHubMessage_Destroy(messageHandle);
}

// ...

PnP_ThermostatComponent_SendTelemetry(g_thermostatHandle1, deviceClient);

只读属性

从默认组件报告属性不需要任何特殊构造:

static const char g_maxTemperatureSinceRebootFormat[] = "{\"maxTempSinceLastReboot\":%.2f}";

char maxTemperatureSinceRebootProperty[256];

snprintf(
    maxTemperatureSinceRebootProperty,
    sizeof(maxTemperatureSinceRebootProperty),
    g_maxTemperatureSinceRebootFormat,
    38.7);

IOTHUB_CLIENT_RESULT iothubClientResult = IoTHubDeviceClient_LL_SendReportedState(
    deviceClientLL,
    (const unsigned char*)maxTemperatureSinceRebootProperty,
    strlen(maxTemperatureSinceRebootProperty), NULL, NULL));

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTempSinceLastReboot" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包括标记:

STRING_HANDLE PnP_CreateReportedProperty(
    const char* componentName,
    const char* propertyName,
    const char* propertyValue
)
{
    STRING_HANDLE jsonToSend;

    if (componentName == NULL) 
    {
        jsonToSend = STRING_construct_sprintf(
            "{\"%s\":%s}",
            propertyName, propertyValue);
    }
    else 
    {
       jsonToSend = STRING_construct_sprintf(
            "{\"""%s\":{\"__t\":\"c\",\"%s\":%s}}",
            componentName, propertyName, propertyValue);
    }

    if (jsonToSend == NULL)
    {
        LogError("Unable to allocate JSON buffer");
    }

    return jsonToSend;
}

void PnP_TempControlComponent_Report_MaxTempSinceLastReboot_Property(
    PNP_THERMOSTAT_COMPONENT_HANDLE pnpThermostatComponentHandle,
    IOTHUB_DEVICE_CLIENT_LL_HANDLE deviceClientLL)
{
    PNP_THERMOSTAT_COMPONENT* pnpThermostatComponent =
        (PNP_THERMOSTAT_COMPONENT*)pnpThermostatComponentHandle;
    char maximumTemperatureAsString[32];
    IOTHUB_CLIENT_RESULT iothubClientResult;
    STRING_HANDLE jsonToSend = NULL;

    if (snprintf(maximumTemperatureAsString, sizeof(maximumTemperatureAsString),
        "%.2f", pnpThermostatComponent->maxTemperature) < 0)
    {
        LogError("Unable to create max temp since last reboot string for reporting result");
    }
    else if ((jsonToSend = PnP_CreateReportedProperty(
                pnpThermostatComponent->componentName,
                g_maxTempSinceLastRebootPropertyName,
                maximumTemperatureAsString)) == NULL)
    {
        LogError("Unable to build max temp since last reboot property");
    }
    else
    {
        const char* jsonToSendStr = STRING_c_str(jsonToSend);
        size_t jsonToSendStrLen = strlen(jsonToSendStr);

        if ((iothubClientResult = IoTHubDeviceClient_LL_SendReportedState(
                deviceClientLL,
                (const unsigned char*)jsonToSendStr,
                jsonToSendStrLen, NULL, NULL)) != IOTHUB_CLIENT_OK)
        {
            LogError("Unable to send reported state, error=%d", iothubClientResult);
        }
        else
        {
            LogInfo("Sending maximumTemperatureSinceLastReboot property to IoTHub for component=%s",
                pnpThermostatComponent->componentName);
        }
    }

    STRING_delete(jsonToSend);
}

// ...

PnP_TempControlComponent_Report_MaxTempSinceLastReboot_Property(g_thermostatHandle1, deviceClient);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1" : {  
      "__t" : "c",  
      "maxTemperature" : 38.7
     }
  }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 如果解决方案更新属性,客户端会接收到通知,即在 DeviceClientModuleClient 中的回调。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

如果属性类型为 Object,则服务必须将完整的对象发送到设备,即使它只更新对象字段的子集,也是如此。 设备发送的确认也可以是一个完整的对象。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

IOTHUB_CLIENT_RESULT iothubClientResult;
char targetTemperatureResponseProperty[256];

snprintf(
    targetTemperatureResponseProperty,
    sizeof(targetTemperatureResponseProperty),
    "{\"targetTemperature\":{\"value\":%.2f,\"ac\":%d,\"av\":%d,\"ad\":\"%s\"}}",
    23.2, 200, 3, "Successfully updated target temperature");

iothubClientResult = IoTHubDeviceClient_LL_SendReportedState(
    deviceClientLL,
    (const unsigned char*)targetTemperatureResponseProperty,
    strlen(targetTemperatureResponseProperty), NULL, NULL);

使用以下报告属性更新设备孪生:

{
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "Successfully updated target temperature"
      }
  }
}

若要从嵌套组件报告可写属性,孪生必须包括标记:

STRING_HANDLE PnP_CreateReportedPropertyWithStatus(const char* componentName,
    const char* propertyName, const char* propertyValue,
    int result, const char* description, int ackVersion
)
{
    STRING_HANDLE jsonToSend;

    if (componentName == NULL) 
    {
        jsonToSend = STRING_construct_sprintf(
            "{\"%s\":{\"value\":%s,\"ac\":%d,\"ad\":\"%s\",\"av\":%d}}",
            propertyName, propertyValue,
            result, description, ackVersion);
    }
    else
    {
       jsonToSend = STRING_construct_sprintf(
            "{\"""%s\":{\"__t\":\"c\",\"%s\":{\"value\":%s,\"ac\":%d,\"ad\":\"%s\",\"av\":%d}}}",
            componentName, propertyName, propertyValue,
            result, description, ackVersion);
    }

    if (jsonToSend == NULL)
    {
        LogError("Unable to allocate JSON buffer");
    }

    return jsonToSend;
}

// ...

char targetTemperatureAsString[32];
IOTHUB_CLIENT_RESULT iothubClientResult;
STRING_HANDLE jsonToSend = NULL;

snprintf(targetTemperatureAsString,
    sizeof(targetTemperatureAsString),
    "%.2f",
    23.2);
jsonToSend = PnP_CreateReportedPropertyWithStatus(
    "thermostat1",
    "targetTemperature",
    targetTemperatureAsString,
    200,
    "complete",
    3);

const char* jsonToSendStr = STRING_c_str(jsonToSend);
size_t jsonToSendStrLen = strlen(jsonToSendStr);

iothubClientResult = IoTHubDeviceClient_LL_SendReportedState(
    deviceClientLL,
    (const unsigned char*)jsonToSendStr,
    jsonToSendStrLen, NULL, NULL);

STRING_delete(jsonToSend);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新后的所需属性,其中包括用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

static void Thermostat_DeviceTwinCallback(
    DEVICE_TWIN_UPDATE_STATE updateState,
    const unsigned char* payload,
    size_t size,
    void* userContextCallback)
{
    // The device handle associated with this request is passed as the context,
    // since we will need to send reported events back.
    IOTHUB_DEVICE_CLIENT_LL_HANDLE deviceClientLL =
        (IOTHUB_DEVICE_CLIENT_LL_HANDLE)userContextCallback;

    char* jsonStr = NULL;
    JSON_Value* rootValue = NULL;
    JSON_Object* desiredObject;
    JSON_Value* versionValue = NULL;
    JSON_Value* targetTemperatureValue = NULL;

    jsonStr = CopyTwinPayloadToString(payload, size));
    rootValue = json_parse_string(jsonStr));
    desiredObject = GetDesiredJson(updateState, rootValue));
    targetTemperatureValue = json_object_get_value(desiredObject, "targetTemperature"));
    versionValue = json_object_get_value(desiredObject, "$version"));
    json_value_get_type(versionValue);
    json_value_get_type(targetTemperatureValue);

    double targetTemperature = json_value_get_number(targetTemperatureValue);
    int version = (int)json_value_get_number(versionValue);

    // ...

    // The device needs to let the service know that it has received the targetTemperature desired property.
    SendTargetTemperatureReport(deviceClientLL, targetTemperature, 200, version, "Successfully updated target temperature");

    json_value_free(rootValue);
    free(jsonStr);
}

// ...

IOTHUB_CLIENT_RESULT iothubResult;
iothubResult = IoTHubDeviceClient_LL_SetDeviceTwinCallback(
    deviceHandle, Thermostat_DeviceTwinCallback, (void*)deviceHandle))

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "targetTemperature": 23.2,
    "$version" : 3
  },
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "Successfully updated target temperature"
      }
  }
}

嵌套组件接收用组件名称包装的所需属性,并且应报告 ack 报告的属性:

bool PnP_ProcessTwinData(
    DEVICE_TWIN_UPDATE_STATE updateState,
    const unsigned char* payload,
    size_t size, const char** componentsInModel,
    size_t numComponentsInModel,
    PnP_PropertyCallbackFunction pnpPropertyCallback,
    void* userContextCallback)
{
    char* jsonStr = NULL;
    JSON_Value* rootValue = NULL;
    JSON_Object* desiredObject;
    bool result;

    jsonStr = PnP_CopyPayloadToString(payload, size));
    rootValue = json_parse_string(jsonStr));
    desiredObject = GetDesiredJson(updateState, rootValue));
    
    result = VisitDesiredObject(
        desiredObject, componentsInModel,
        numComponentsInModel, pnpPropertyCallback,
        userContextCallback);


    json_value_free(rootValue);
    free(jsonStr);

    return result;
}

// ...
static const char g_thermostatComponent1Name[] = "thermostat1";
static const size_t g_thermostatComponent1Size = sizeof(g_thermostatComponent1Name) - 1;
static const char g_thermostatComponent2Name[] = "thermostat2";

static const char* g_modeledComponents[] = {g_thermostatComponent1Name, g_thermostatComponent2Name};
static const size_t g_numModeledComponents = sizeof(g_modeledComponents) / sizeof(g_modeledComponents[0]);

static void PnP_TempControlComponent_DeviceTwinCallback(
    DEVICE_TWIN_UPDATE_STATE updateState,
    const unsigned char* payload,
    size_t size,
    void* userContextCallback
)
{
    PnP_ProcessTwinData(
        updateState, payload,
        size, g_modeledComponents,
        g_numModeledComponents,
        PnP_TempControlComponent_ApplicationPropertyCallback,
        userContextCallback);
}

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。

void PnP_ParseCommandName(
    const char* deviceMethodName,
    unsigned const char** componentName,
    size_t* componentNameSize,
    const char** pnpCommandName
)
{
    const char* separator;

    if ((separator = strchr(deviceMethodName, "*")) != NULL)
    {
        *componentName = (unsigned const char*)deviceMethodName;
        *componentNameSize = separator - deviceMethodName;
        *pnpCommandName = separator + 1;
    }
    else
    {
        *componentName = NULL;
        *componentNameSize = 0;
        *pnpCommandName = deviceMethodName;
    }
}

static int PnP_TempControlComponent_DeviceMethodCallback(
    const char* methodName,
    const unsigned char* payload,
    size_t size,
    unsigned char** response,
    size_t* responseSize,
    void* userContextCallback)
{
    (void)userContextCallback;

    char* jsonStr = NULL;
    JSON_Value* rootValue = NULL;
    int result;
    unsigned const char *componentName;
    size_t componentNameSize;
    const char *pnpCommandName;

    *response = NULL;
    *responseSize = 0;

    // Parse the methodName into its componentName and CommandName.
    PnP_ParseCommandName(methodName, &componentName, &componentNameSize, &pnpCommandName);

    // Parse the JSON of the payload request.
    jsonStr = PnP_CopyPayloadToString(payload, size));
    rootValue = json_parse_string(jsonStr));
    if (componentName != NULL)
    {
        if (strncmp((const char*)componentName, g_thermostatComponent1Name, g_thermostatComponent1Size) == 0)
        {
            result = PnP_ThermostatComponent_ProcessCommand(g_thermostatHandle1, pnpCommandName, rootValue, response, responseSize);
        }
        else if (strncmp((const char*)componentName, g_thermostatComponent2Name, g_thermostatComponent2Size) == 0)
        {
            result = PnP_ThermostatComponent_ProcessCommand(g_thermostatHandle2, pnpCommandName, rootValue, response, responseSize);
        }
        else
        {
            LogError("PnP component=%.*s is not supported by TemperatureController", (int)componentNameSize, componentName);
            result = PNP_STATUS_NOT_FOUND;
        }
    }
    else
    {
        LogInfo("Received PnP command for TemperatureController component, command=%s", pnpCommandName);
        if (strcmp(pnpCommandName, g_rebootCommand) == 0)
        {
            result = PnP_TempControlComponent_InvokeRebootCommand(rootValue);
        }
        else
        {
            LogError("PnP command=s%s is not supported by TemperatureController", pnpCommandName);
            result = PNP_STATUS_NOT_FOUND;
        }
    }

    if (*response == NULL)
    {
        SetEmptyCommandResponse(response, responseSize, &result);
    }

    json_value_free(rootValue);
    free(jsonStr);

    return result;
}

// ...

PNP_DEVICE_CONFIGURATION g_pnpDeviceConfiguration;
g_pnpDeviceConfiguration.deviceMethodCallback = PnP_TempControlComponent_DeviceMethodCallback;
deviceClient = PnP_CreateDeviceClientLLHandle(&g_pnpDeviceConfiguration);

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。

下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "getMaxMinReport",
  "displayName": "Get Max-Min report.",
  "description": "This command returns the max, min and average temperature from the specified time to the current time.",
  "request": {
    "name": "since",
    "displayName": "Since",
    "description": "Period to return the max-min report.",
    "schema": "dateTime"
  },
  "response": {
    "name" : "tempReport",
    "displayName": "Temperature Report",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "maxTemp",
          "displayName": "Max temperature",
          "schema": "double"
        },
        {
          "name": "minTemp",
          "displayName": "Min temperature",
          "schema": "double"
        },
        {
          "name" : "avgTemp",
          "displayName": "Average Temperature",
          "schema": "double"
        },
        {
          "name" : "startTime",
          "displayName": "Start Time",
          "schema": "dateTime"
        },
        {
          "name" : "endTime",
          "displayName": "End Time",
          "schema": "dateTime"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

static const char g_maxMinCommandResponseFormat[] = "{\"maxTemp\":%.2f,\"minTemp\":%.2f,\"avgTemp\":%.2f,\"startTime\":\"%s\",\"endTime\":\"%s\"}";

// ...

static bool BuildMaxMinCommandResponse(
    PNP_THERMOSTAT_COMPONENT* pnpThermostatComponent,
    unsigned char** response,
    size_t* responseSize)
{
    int responseBuilderSize = 0;
    unsigned char* responseBuilder = NULL;
    bool result;
    char currentTime[TIME_BUFFER_SIZE];

    BuildUtcTimeFromCurrentTime(currentTime, sizeof(currentTime));
    responseBuilderSize = snprintf(NULL, 0, g_maxMinCommandResponseFormat,
        pnpThermostatComponent->maxTemperature,
        pnpThermostatComponent->minTemperature,
        pnpThermostatComponent->allTemperatures /
        pnpThermostatComponent->numTemperatureUpdates,
        g_programStartTime, currentTime));

    responseBuilder = calloc(1, responseBuilderSize + 1));

    responseBuilderSize = snprintf(
        (char*)responseBuilder, responseBuilderSize + 1, g_maxMinCommandResponseFormat,
        pnpThermostatComponent->maxTemperature,
        pnpThermostatComponent->minTemperature,
        pnpThermostatComponent->allTemperatures / pnpThermostatComponent->numTemperatureUpdates,
        g_programStartTime,
        currentTime));

    *response = responseBuilder;
    *responseSize = (size_t)responseBuilderSize;

    return true;
}

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

SDK

本文中的代码片段基于那些使用 Azure RTOS 的 Azure IoT 中间件加载项的示例。 此加载项是 Azure RTOSAzure SDK for Embedded C 之间的绑定层。

本文中的代码片段基于以下示例:

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

#include "nx_azure_iot_hub_client.h"

// ...

#define SAMPLE_PNP_MODEL_ID "dtmi:com:example:Thermostat;1"

// ...

status = nx_azure_iot_hub_client_model_id_set(iothub_client_ptr, (UCHAR *)SAMPLE_PNP_MODEL_ID, sizeof(SAMPLE_PNP_MODEL_ID) - 1);

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

此示例使用以下代码来发送此有效负载:

#include "nx_azure_iot_provisioning_client.h"

// ...

#define SAMPLE_PNP_MODEL_ID "dtmi:com:example:Thermostat;1"
#define SAMPLE_PNP_DPS_PAYLOAD "{\"modelId\":\"" SAMPLE_PNP_MODEL_ID "\"}"

// ...

status = nx_azure_iot_provisioning_client_registration_payload_set(prov_client_ptr, (UCHAR *)SAMPLE_PNP_DPS_PAYLOAD, sizeof(SAMPLE_PNP_DPS_PAYLOAD) - 1);

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则。 为了简化针对组件的 IoT 即插即用约定的使用,示例使用了 nx_azure_iot_hub_client.h 中的帮助程序函数。

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性。 在以下代码片段中,component_name_ptr 是组件(例如 thermostat1)的名称。 在 nx_azure_iot_pnp_helpers.h 中定义的帮助程序函数 nx_azure_iot_pnp_helper_telemetry_message_create 会添加包含组件名称的消息属性:

#include "nx_azure_iot_pnp_helpers.h"

// ...

static const CHAR telemetry_name[] = "temperature";

// ...

UINT sample_pnp_thermostat_telemetry_send(SAMPLE_PNP_THERMOSTAT_COMPONENT *handle, NX_AZURE_IOT_HUB_CLIENT *iothub_client_ptr)
{
UINT status;
NX_PACKET *packet_ptr;
NX_AZURE_IOT_JSON_WRITER json_writer;
UINT buffer_length;

    // ...

    /* Create a telemetry message packet. */
    if ((status = nx_azure_iot_pnp_helper_telemetry_message_create(iothub_client_ptr, handle -> component_name_ptr,
        handle -> component_name_length,
        &packet_ptr, NX_WAIT_FOREVER)))
    {
        // ...
    }

    // ...

    if ((status = nx_azure_iot_hub_client_telemetry_send(iothub_client_ptr, packet_ptr,
        (UCHAR *)scratch_buffer, buffer_length, NX_WAIT_FOREVER)))
    {
        // ...
    }

    // ...

    return(status);
}

只读属性

从默认组件报告属性不需要任何特殊构造:

#include "nx_azure_iot_hub_client.h"
#include "nx_azure_iot_json_writer.h"

// ...

static const CHAR reported_max_temp_since_last_reboot[] = "maxTempSinceLastReboot";

// ...

static UINT sample_build_reported_property(NX_AZURE_IOT_JSON_WRITER *json_builder_ptr, double temp)
{
UINT ret;

    if (nx_azure_iot_json_writer_append_begin_object(json_builder_ptr) ||
        nx_azure_iot_json_writer_append_property_with_double_value(json_builder_ptr,
            (UCHAR *)reported_max_temp_since_last_reboot,
            sizeof(reported_max_temp_since_last_reboot) - 1,
            temp, DOUBLE_DECIMAL_PLACE_DIGITS) ||
        nx_azure_iot_json_writer_append_end_object(json_builder_ptr))
    {
        ret = 1;
        printf("Failed to build reported property\r\n");
    }
    else
    {
        ret = 0;
    }

    return(ret);
}

// ...

if ((status = sample_build_reported_property(&json_builder, device_max_temp)))
{
    // ...
}

reported_properties_length = nx_azure_iot_json_writer_get_bytes_used(&json_builder);
if ((status = nx_azure_iot_hub_client_device_twin_reported_properties_send(&(context -> iothub_client),
    scratch_buffer,
    reported_properties_length,
    &request_id, &response_status,
    &reported_property_version,
    (5 * NX_IP_PERIODIC_RATE))))
{
    // ...
}

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTempSinceLastReboot" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包含一个标记。 在以下代码片段中,component_name_ptr 是组件(例如 thermostat1)的名称。 在 nx_azure_iot_pnp_helpers.h 中定义的帮助程序函数 nx_azure_iot_pnp_helper_build_reported_property 会以正确的格式创建报告的属性:

#include "nx_azure_iot_pnp_helpers.h"

// ...

static const CHAR reported_max_temp_since_last_reboot[] = "maxTempSinceLastReboot";

UINT sample_pnp_thermostat_report_max_temp_since_last_reboot_property(SAMPLE_PNP_THERMOSTAT_COMPONENT *handle, NX_AZURE_IOT_HUB_CLIENT *iothub_client_ptr)
{
UINT reported_properties_length;
UINT status;
UINT response_status;
UINT request_id;
NX_AZURE_IOT_JSON_WRITER json_builder;
ULONG reported_property_version;

    // ...

    if ((status = nx_azure_iot_pnp_helper_build_reported_property(handle -> component_name_ptr,
        handle -> component_name_length,
        append_max_temp, (VOID *)handle,
        &json_builder)))
    {
        // ...
    }

    reported_properties_length = nx_azure_iot_json_writer_get_bytes_used(&json_builder);
    if ((status = nx_azure_iot_hub_client_device_twin_reported_properties_send(iothub_client_ptr,
        scratch_buffer,
        reported_properties_length,
        &request_id, &response_status,
        &reported_property_version,
        (5 * NX_IP_PERIODIC_RATE))))
    {
        // ...
    }

    // ...
}

使用以下报告属性更新设备孪生:

{
    "reported": {
        "thermostat1" : {  
            "__t" : "c",  
            "maxTemperature" : 38.7
        } 
    }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

#include "nx_azure_iot_hub_client.h"
#include "nx_azure_iot_json_writer.h"

// ...

static const CHAR reported_temp_property_name[] = "targetTemperature";
static const CHAR reported_value_property_name[] = "value";
static const CHAR reported_status_property_name[] = "ac";
static const CHAR reported_version_property_name[] = "av";
static const CHAR reported_description_property_name[] = "ad";

// ...

static VOID sample_send_target_temperature_report(SAMPLE_CONTEXT *context, double current_device_temp_value,
    UINT status, UINT version, UCHAR *description_ptr,
    UINT description_len)
{
NX_AZURE_IOT_JSON_WRITER json_builder;
UINT bytes_copied;
UINT response_status;
UINT request_id;
ULONG reported_property_version;

    // ...

    if (nx_azure_iot_json_writer_append_begin_object(&json_builder) ||
        nx_azure_iot_json_writer_append_property_name(&json_builder,
            (UCHAR *)reported_temp_property_name,
            sizeof(reported_temp_property_name) - 1) ||
        nx_azure_iot_json_writer_append_begin_object(&json_builder) ||
        nx_azure_iot_json_writer_append_property_with_double_value(&json_builder,
            (UCHAR *)reported_value_property_name,
            sizeof(reported_value_property_name) - 1,
            current_device_temp_value, DOUBLE_DECIMAL_PLACE_DIGITS) ||
        nx_azure_iot_json_writer_append_property_with_int32_value(&json_builder,
            (UCHAR *)reported_status_property_name,
            sizeof(reported_status_property_name) - 1,
            (int32_t)status) ||
        nx_azure_iot_json_writer_append_property_with_int32_value(&json_builder,
            (UCHAR *)reported_version_property_name,
            sizeof(reported_version_property_name) - 1,
            (int32_t)version) ||
        nx_azure_iot_json_writer_append_property_with_string_value(&json_builder,
            (UCHAR *)reported_description_property_name,
            sizeof(reported_description_property_name) - 1,
            description_ptr, description_len) ||
        nx_azure_iot_json_writer_append_end_object(&json_builder) ||
        nx_azure_iot_json_writer_append_end_object(&json_builder))
    {
        // ...
    }
    else
    // ...
}

使用以下报告属性更新设备孪生:

{
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "success"
      }
  }
}

若要从嵌套的组件报告可写属性,孪生体必须包含一个标记,并且属性必须在组件名称中创建。 在以下代码片段中,component_name_ptr 是组件(例如 thermostat1)的名称。 在 nx_azure_iot_pnp_helpers.h 中定义的帮助程序函数 nx_azure_iot_pnp_helper_build_reported_property_with_status 会创建报告属性有效负载:

#include "nx_azure_iot_pnp_helpers.h"

// ...

static VOID sample_send_target_temperature_report(SAMPLE_PNP_THERMOSTAT_COMPONENT *handle,
    NX_AZURE_IOT_HUB_CLIENT *iothub_client_ptr, double temp,
    INT status_code, UINT version, const CHAR *description)
{
UINT bytes_copied;
UINT response_status;
UINT request_id;
NX_AZURE_IOT_JSON_WRITER json_writer;
ULONG reported_property_version;

    // ...

    if (nx_azure_iot_pnp_helper_build_reported_property_with_status(handle -> component_name_ptr, handle -> component_name_length,
        (UCHAR *)target_temp_property_name,
        sizeof(target_temp_property_name) - 1,
        append_temp, (VOID *)&temp, status_code,
        (UCHAR *)description,
        strlen(description), version, &json_writer))
    {
        // ...
    }
    else
    {
        // ...
    }

    // ...
}

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "success"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新的所需属性和用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

#include "nx_azure_iot_hub_client.h"
#include "nx_azure_iot_json_writer.h"

// ...

static const CHAR temp_response_description[] = "success";

// ...

static UINT sample_parse_desired_temp_property(SAMPLE_CONTEXT *context,
    NX_AZURE_IOT_JSON_READER *json_reader_ptr,
    UINT is_partial)
{
double parsed_value;
UINT version;
NX_AZURE_IOT_JSON_READER copy_json_reader;
UINT status;

    // ...

    copy_json_reader = *json_reader_ptr;
    if (sample_json_child_token_move(&copy_json_reader,
            (UCHAR *)desired_version_property_name,
            sizeof(desired_version_property_name) - 1) ||
        nx_azure_iot_json_reader_token_int32_get(&copy_json_reader, (int32_t *)&version))
    {
        // ...
    }

    // ...

    sample_send_target_temperature_report(context, current_device_temp, 200,
        (UINT)version, (UCHAR *)temp_response_description,
        sizeof(temp_response_description) - 1);

    // ...
}

嵌套组件接收用组件名称包装的所需属性,并使用接收的版本创建报告的 ack

#include "nx_azure_iot_pnp_helpers.h"

// ...

static const CHAR target_temp_property_name[] = "targetTemperature";
static const CHAR temp_response_description_success[] = "success";
static const CHAR temp_response_description_failed[] = "failed";

// ...

UINT sample_pnp_thermostat_process_property_update(SAMPLE_PNP_THERMOSTAT_COMPONENT *handle,
    NX_AZURE_IOT_HUB_CLIENT *iothub_client_ptr,
    UCHAR *component_name_ptr, UINT component_name_length,
    UCHAR *property_name_ptr, UINT property_name_length,
    NX_AZURE_IOT_JSON_READER *property_value_reader_ptr, UINT version)
{
double parsed_value = 0;
INT status_code;
const CHAR *description;

    // ...

    if (property_name_length != (sizeof(target_temp_property_name) - 1) ||
        strncmp((CHAR *)property_name_ptr, (CHAR *)target_temp_property_name, property_name_length) != 0)
    {
        // ...
    }
    else if (nx_azure_iot_json_reader_token_double_get(property_value_reader_ptr, &parsed_value))
    {
        status_code = 401;
        description = temp_response_description_failed;
    }
    else
    {
        status_code = 200;
        description = temp_response_description_success;

        // ...
    }

    sample_send_target_temperature_report(handle, iothub_client_ptr, parsed_value,
                                          status_code, version, description);

    // ...
}

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "success"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。 在以下代码片段中,在 nx_azure_iot_pnp_helpers.h 中定义的帮助程序函数 nx_azure_iot_pnp_helper_command_name_parse 将分析设备从服务接收的消息中的组件名称和命令名称:

#include "nx_azure_iot_hub_client.h"
#include "nx_azure_iot_pnp_helpers.h"

// ...

static VOID sample_direct_method_action(SAMPLE_CONTEXT *sample_context_ptr)
{
NX_PACKET *packet_ptr;
UINT status;
USHORT method_name_length;
const UCHAR *method_name_ptr;
USHORT context_length;
VOID *context_ptr;
UINT component_name_length;
const UCHAR *component_name_ptr;
UINT pnp_command_name_length;
const UCHAR *pnp_command_name_ptr;
NX_AZURE_IOT_JSON_WRITER json_writer;
NX_AZURE_IOT_JSON_READER json_reader;
NX_AZURE_IOT_JSON_READER *json_reader_ptr;
UINT status_code;
UINT response_length;

    // ...

    if ((status = nx_azure_iot_hub_client_direct_method_message_receive(&(sample_context_ptr -> iothub_client),
        &method_name_ptr, &method_name_length,
        &context_ptr, &context_length,
        &packet_ptr, NX_WAIT_FOREVER)))
    {
        // ...
    }

    // ...

    if ((status = nx_azure_iot_pnp_helper_command_name_parse(method_name_ptr, method_name_length,
        &component_name_ptr, &component_name_length,
        &pnp_command_name_ptr,
        &pnp_command_name_length)) != NX_AZURE_IOT_SUCCESS)
    {
        // ...
    }
    
    // ...

    else
    {
        // ...

        if ((status = sample_pnp_thermostat_process_command(&sample_thermostat_1, component_name_ptr,
            component_name_length, pnp_command_name_ptr,
            pnp_command_name_length, json_reader_ptr,
            &json_writer, &status_code)) == NX_AZURE_IOT_SUCCESS)
        {
            // ...
        }
        else if ((status = sample_pnp_thermostat_process_command(&sample_thermostat_2, component_name_ptr,
            component_name_length, pnp_command_name_ptr,
            pnp_command_name_length, json_reader_ptr,
            &json_writer, &status_code)) == NX_AZURE_IOT_SUCCESS)
        {
            // ...
        }
        else if((status = sample_pnp_temp_controller_process_command(component_name_ptr, component_name_length,
            pnp_command_name_ptr, pnp_command_name_length,
            json_reader_ptr, &json_writer,
            &status_code)) == NX_AZURE_IOT_SUCCESS)
        {
            // ...
        }
        else
        {
            printf("Failed to find any handler for method %.*s\r\n", method_name_length, method_name_ptr);
            status_code = SAMPLE_COMMAND_NOT_FOUND_STATUS;
            response_length = 0;
        }

        // ...
    }
}

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。

下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "getMaxMinReport",
  "displayName": "Get Max-Min report.",
  "description": "This command returns the max, min and average temperature from the specified time to the current time.",
  "request": {
    "name": "since",
    "displayName": "Since",
    "description": "Period to return the max-min report.",
    "schema": "dateTime"
  },
  "response": {
    "name" : "tempReport",
    "displayName": "Temperature Report",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "maxTemp",
          "displayName": "Max temperature",
          "schema": "double"
        },
        {
          "name": "minTemp",
          "displayName": "Min temperature",
          "schema": "double"
        },
        {
          "name" : "avgTemp",
          "displayName": "Average Temperature",
          "schema": "double"
        },
        {
          "name" : "startTime",
          "displayName": "Start Time",
          "schema": "dateTime"
        },
        {
          "name" : "endTime",
          "displayName": "End Time",
          "schema": "dateTime"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

#include "nx_azure_iot_pnp_helpers.h"

// ...

static const CHAR report_max_temp_name[] = "maxTemp";
static const CHAR report_min_temp_name[] = "minTemp";
static const CHAR report_avg_temp_name[] = "avgTemp";
static const CHAR report_start_time_name[] = "startTime";
static const CHAR report_end_time_name[] = "endTime";
static const CHAR fake_start_report_time[] = "2020-01-10T10:00:00Z";
static const CHAR fake_end_report_time[] = "2023-01-10T10:00:00Z";

// ...

static UINT sample_get_maxmin_report(SAMPLE_PNP_THERMOSTAT_COMPONENT *handle,
    NX_AZURE_IOT_JSON_READER *json_reader_ptr,
    NX_AZURE_IOT_JSON_WRITER *out_json_builder_ptr)
{
UINT status;
UCHAR *start_time = (UCHAR *)fake_start_report_time;
UINT start_time_len = sizeof(fake_start_report_time) - 1;
UCHAR time_buf[32];

    // ...

    /* Build the method response payload */
    if (nx_azure_iot_json_writer_append_begin_object(out_json_builder_ptr) ||
        nx_azure_iot_json_writer_append_property_with_double_value(out_json_builder_ptr,
            (UCHAR *)report_max_temp_name,
            sizeof(report_max_temp_name) - 1,
            handle -> maxTemperature,
            DOUBLE_DECIMAL_PLACE_DIGITS) ||
        nx_azure_iot_json_writer_append_property_with_double_value(out_json_builder_ptr,
            (UCHAR *)report_min_temp_name,
            sizeof(report_min_temp_name) - 1,
            handle -> minTemperature,
            DOUBLE_DECIMAL_PLACE_DIGITS) ||
        nx_azure_iot_json_writer_append_property_with_double_value(out_json_builder_ptr,
            (UCHAR *)report_avg_temp_name,
            sizeof(report_avg_temp_name) - 1,
            handle -> avgTemperature,
            DOUBLE_DECIMAL_PLACE_DIGITS) ||
        nx_azure_iot_json_writer_append_property_with_string_value(out_json_builder_ptr,
            (UCHAR *)report_start_time_name,
            sizeof(report_start_time_name) - 1,
            (UCHAR *)start_time, start_time_len) ||
        nx_azure_iot_json_writer_append_property_with_string_value(out_json_builder_ptr,
            (UCHAR *)report_end_time_name,
            sizeof(report_end_time_name) - 1,
            (UCHAR *)fake_end_report_time,
            sizeof(fake_end_report_time) - 1) ||
        nx_azure_iot_json_writer_append_end_object(out_json_builder_ptr))
    {
        status = NX_NOT_SUCCESSFUL;
    }
    else
    {
        status = NX_AZURE_IOT_SUCCESS;
    }

    return(status);
}

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

DeviceClient.CreateFromConnectionString(
  connectionString,
  TransportType.Mqtt,
  new ClientOptions() { ModelId = modelId })

新的 ClientOptions 重载在用于初始化连接的所有 DeviceClient 方法中可用。

提示

对于模块和 IoT Edge,使用 ModuleClient 代替 DeviceClient

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则。

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性:

public async Task SendComponentTelemetryValueAsync(string componentName, string serializedTelemetry)
{
  var message = new Message(Encoding.UTF8.GetBytes(serializedTelemetry));
  message.ComponentName = componentName;
  message.ContentType = "application/json";
  message.ContentEncoding = "utf-8";
  await client.SendEventAsync(message);
}

只读属性

从默认组件报告属性不需要任何特殊构造:

TwinCollection reportedProperties = new TwinCollection();
reportedProperties["maxTemperature"] = 38.7;
await client.UpdateReportedPropertiesAsync(reportedProperties);

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTemperature" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包括标记:

TwinCollection reportedProperties = new TwinCollection();
TwinCollection component = new TwinCollection();
component["maxTemperature"] = 38.7;
component["__t"] = "c"; // marker to identify a component
reportedProperties["thermostat1"] = component;
await client.UpdateReportedPropertiesAsync(reportedProperties);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1" : {  
      "__t" : "c",  
      "maxTemperature" : 38.7
     } 
  }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 如果解决方案更新属性,客户端会接收到通知,即在 DeviceClientModuleClient 中的回调。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

如果属性类型为 Object,则服务必须将完整的对象发送到设备,即使它只更新对象字段的子集,也是如此。 设备发送的确认也必须是完整的对象。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

TwinCollection reportedProperties = new TwinCollection();
TwinCollection ackProps = new TwinCollection();
ackProps["value"] = 23.2;
ackProps["ac"] = 200; // using HTTP status codes
ackProps["av"] = 0; // not readed from a desired property
ackProps["ad"] = "reported default value";
reportedProperties["targetTemperature"] = ackProps;
await client.UpdateReportedPropertiesAsync(reportedProperties);

使用以下报告属性更新设备孪生:

{
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
  }
}

若要从嵌套组件报告可写属性,孪生必须包括标记:

TwinCollection reportedProperties = new TwinCollection();
TwinCollection component = new TwinCollection();
TwinCollection ackProps = new TwinCollection();
component["__t"] = "c"; // marker to identify a component
ackProps["value"] = 23.2;
ackProps["ac"] = 200; // using HTTP status codes
ackProps["av"] = 0; // not read from a desired property
ackProps["ad"] = "reported default value";
component["targetTemperature"] = ackProps;
reportedProperties["thermostat1"] = component;
await client.UpdateReportedPropertiesAsync(reportedProperties);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新后的所需属性,其中包括用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

await client.SetDesiredPropertyUpdateCallbackAsync(async (desired, ctx) => 
{
  JValue targetTempJson = desired["targetTemperature"];
  double targetTemperature = targetTempJson.Value<double>();

  TwinCollection reportedProperties = new TwinCollection();
  TwinCollection ackProps = new TwinCollection();
  ackProps["value"] = targetTemperature;
  ackProps["ac"] = 200;
  ackProps["av"] = desired.Version; 
  ackProps["ad"] = "desired property received";
  reportedProperties["targetTemperature"] = ackProps;

  await client.UpdateReportedPropertiesAsync(reportedProperties);
}, null);

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "targetTemperature": 23.2,
    "$version" : 3
  },
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
  }
}

嵌套组件接收用组件名称包装的所需属性,并且应报告 ack 报告的属性:

await client.SetDesiredPropertyUpdateCallbackAsync(async (desired, ctx) =>
{
  JObject thermostatComponent = desired["thermostat1"];
  JToken targetTempProp = thermostatComponent["targetTemperature"];
  double targetTemperature = targetTempProp.Value<double>();

  TwinCollection reportedProperties = new TwinCollection();
  TwinCollection component = new TwinCollection();
  TwinCollection ackProps = new TwinCollection();
  component["__t"] = "c"; // marker to identify a component
  ackProps["value"] = targetTemperature;
  ackProps["ac"] = 200; // using HTTP status codes
  ackProps["av"] = desired.Version; // not readed from a desired property
  ackProps["ad"] = "desired property received";
  component["targetTemperature"] = ackProps;
  reportedProperties["thermostat1"] = component;

  await client.UpdateReportedPropertiesAsync(reportedProperties);
}, null);

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。

await client.SetMethodHandlerAsync("themostat*reboot", (MethodRequest req, object ctx) =>
{
  Console.WriteLine("REBOOT");
  return Task.FromResult(new MethodResponse(200));
},
null);

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。 下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "start",
  "request": {
    "name": "startRequest",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "startPriority",
          "schema": "integer"
        },
        {
          "name": "startMessage",
          "schema" : "string"
        }
      ]
    }
  },
  "response": {
    "name": "startReponse",
    "schema": {
      "@type": "Object",
      "fields": [
        {
            "name": "startupTime",
            "schema": "integer" 
        },
        {
          "name": "startupMessage",
          "schema": "string"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

class startRequest
{
  public int startPriority { get; set; }
  public string startMessage { get; set; }
}

class startResponse
{
  public int startupTime { get; set; }
  public string startupMessage { get; set; }
}

// ... 

await client.SetMethodHandlerAsync("start", (MethodRequest req, object ctx) =>
{
  var startRequest = JsonConvert.DeserializeObject<startRequest>(req.DataAsJson);
  Console.WriteLine($"Received start command with priority ${startRequest.startPriority} and ${startRequest.startMessage}");

  var startResponse = new startResponse
  {
    startupTime = 123,
    startupMessage = "device started with message " + startRequest.startMessage
  };

  string responsePayload = JsonConvert.SerializeObject(startResponse);
  MethodResponse response = new MethodResponse(Encoding.UTF8.GetBytes(responsePayload), 200);
  return Task.FromResult(response);
},null);

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

ClientOptions options = new ClientOptions();
options.setModelId(MODEL_ID);
deviceClient = new DeviceClient(deviceConnectionString, protocol, options);

ClientOptions 重载在用于初始化连接的所有 DeviceClient 方法中均可用。

提示

对于模块和 IoT Edge,使用 ModuleClient 代替 DeviceClient

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则。

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性:

private static void sendTemperatureTelemetry(String componentName) {
  double currentTemperature = temperature.get(componentName);

  Map<String, Object> payload = singletonMap("temperature", currentTemperature);

  Message message = new Message(gson.toJson(payload));
  message.setContentEncoding("utf-8");
  message.setContentTypeFinal("application/json");

  if (componentName != null) {
      message.setProperty("$.sub", componentName);
  }
  deviceClient.sendEventAsync(message, new MessageIotHubEventCallback(), message);
}

只读属性

从默认组件报告属性不需要任何特殊构造:

Property reportedProperty = new Property("maxTempSinceLastReboot", 38.7);

deviceClient.sendReportedProperties(Collections.singleton(reportedProperty));

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTempSinceLastReboot" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包括标记:

Map<String, Object> componentProperty = new HashMap<String, Object>() {{
    put("__t", "c");
    put("maxTemperature", 38.7);
}};

Set<Property> reportedProperty = new Property("thermostat1", componentProperty)

deviceClient.sendReportedProperties(reportedProperty);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1" : {  
      "__t" : "c",  
      "maxTemperature" : 38.7
     }
  }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 如果解决方案更新属性,客户端会接收到通知,即在 DeviceClientModuleClient 中的回调。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

如果属性类型为 Object,则服务必须将完整的对象发送到设备,即使它只更新对象字段的子集,也是如此。 设备发送的确认也必须是完整的对象。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

@AllArgsConstructor
private static class EmbeddedPropertyUpdate {
  @NonNull
  @SerializedName("value")
  public Object value;
  @NonNull
  @SerializedName("ac")
  public Integer ackCode;
  @NonNull
  @SerializedName("av")
  public Integer ackVersion;
  @SerializedName("ad")
  public String ackDescription;
}

EmbeddedPropertyUpdate completedUpdate = new EmbeddedPropertyUpdate(23.2, 200, 3, "Successfully updated target temperature");
Property reportedPropertyCompleted = new Property("targetTemperature", completedUpdate);
deviceClient.sendReportedProperties(Collections.singleton(reportedPropertyCompleted));

使用以下报告属性更新设备孪生:

{
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "Successfully updated target temperature"
      }
  }
}

若要从嵌套组件报告可写属性,孪生必须包括标记:

Map<String, Object> embeddedProperty = new HashMap<String, Object>() {{
    put("value", 23.2);
    put("ac", 200);
    put("av", 3);
    put("ad", "complete");
}};

Map<String, Object> componentProperty = new HashMap<String, Object>() {{
    put("__t", "c");
    put("targetTemperature", embeddedProperty);
}};

Set<Property> reportedProperty = new Property("thermostat1", componentProperty));

deviceClient.sendReportedProperties(reportedProperty);

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新后的所需属性,其中包括用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

private static class TargetTemperatureUpdateCallback implements TwinPropertyCallBack {

    String propertyName = "targetTemperature";

    @Override
    public void TwinPropertyCallBack(Property property, Object context) {
        double targetTemperature = ((Number)property.getValue()).doubleValue();

        EmbeddedPropertyUpdate completedUpdate = new EmbeddedPropertyUpdate(temperature, 200, property.getVersion(), "Successfully updated target temperature");
        Property reportedPropertyCompleted = new Property(propertyName, completedUpdate);
        deviceClient.sendReportedProperties(Collections.singleton(reportedPropertyCompleted));
    }
}

// ...

deviceClient.startDeviceTwin(new TwinIotHubEventCallback(), null, new TargetTemperatureUpdateCallback(), null);
Map<Property, Pair<TwinPropertyCallBack, Object>> desiredPropertyUpdateCallback =
  Collections.singletonMap(
    new Property("targetTemperature", null),
    new Pair<>(new TargetTemperatureUpdateCallback(), null));
deviceClient.subscribeToTwinDesiredProperties(desiredPropertyUpdateCallback);

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "targetTemperature": 23.2,
    "$version" : 3
  },
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "Successfully updated target temperature"
      }
  }
}

嵌套组件接收用组件名称包装的所需属性,并且应报告 ack 报告的属性:

private static final Map<String, Double> temperature = new HashMap<>();

private static class TargetTemperatureUpdateCallback implements TwinPropertyCallBack {

    String propertyName = "targetTemperature";

    @Override
    public void TwinPropertyCallBack(Property property, Object context) {
        String componentName = (String) context;

        if (property.getKey().equalsIgnoreCase(componentName)) {
            double targetTemperature = (double) ((TwinCollection) property.getValue()).get(propertyName);

            Map<String, Object> embeddedProperty = new HashMap<String, Object>() {{
                put("value", temperature.get(componentName));
                put("ac", 200);
                put("av", property.getVersion().longValue());
                put("ad", "Successfully updated target temperature.");
            }};

            Map<String, Object> componentProperty = new HashMap<String, Object>() {{
                put("__t", "c");
                put(propertyName, embeddedProperty);
            }};

            Set<Property> completedPropertyPatch = new Property(componentName, componentProperty));

            deviceClient.sendReportedProperties(completedPropertyPatch);
        } else {
            log.debug("Property: Received an unrecognized property update from service.");
        }
    }
}

// ...

deviceClient.startDeviceTwin(new TwinIotHubEventCallback(), null, new GenericPropertyUpdateCallback(), null);
Map<Property, Pair<TwinPropertyCallBack, Object>> desiredPropertyUpdateCallback = Stream.of(
  new AbstractMap.SimpleEntry<Property, Pair<TwinPropertyCallBack, Object>>(
    new Property("thermostat1", null),
    new Pair<>(new TargetTemperatureUpdateCallback(), "thermostat1")),
  new AbstractMap.SimpleEntry<Property, Pair<TwinPropertyCallBack, Object>>(
    new Property("thermostat2", null),
    new Pair<>(new TargetTemperatureUpdateCallback(), "thermostat2"))
).collect(Collectors.toMap(AbstractMap.SimpleEntry::getKey, AbstractMap.SimpleEntry::getValue));

deviceClient.subscribeToTwinDesiredProperties(desiredPropertyUpdateCallback);

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。

deviceClient.subscribeToDeviceMethod(new MethodCallback(), null, new MethodIotHubEventCallback(), null);

// ...
private static final Map<String, Double> temperature = new HashMap<>();

private static class MethodCallback implements DeviceMethodCallback {
  final String reboot = "reboot";
  final String getMaxMinReport1 = "thermostat1*getMaxMinReport";
  final String getMaxMinReport2 = "thermostat2*getMaxMinReport";

  @Override
  public DeviceMethodData call(String methodName, Object methodData, Object context) {
    String jsonRequest = new String((byte[]) methodData, StandardCharsets.UTF_8);

    switch (methodName) {
      case reboot:
        int delay = gson.fromJson(jsonRequest, Integer.class);

        Thread.sleep(delay * 1000);

        temperature.put("thermostat1", 0.0d);
        temperature.put("thermostat2", 0.0d);

        return new DeviceMethodData(200, null);

      // ...

      default:
        log.debug("Command: command=\"{}\" is not implemented, no action taken.", methodName);
          return new DeviceMethodData(404, null);
    }
  }
}

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。

下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "getMaxMinReport",
  "displayName": "Get Max-Min report.",
  "description": "This command returns the max, min and average temperature from the specified time to the current time.",
  "request": {
    "name": "since",
    "displayName": "Since",
    "description": "Period to return the max-min report.",
    "schema": "dateTime"
  },
  "response": {
    "name" : "tempReport",
    "displayName": "Temperature Report",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "maxTemp",
          "displayName": "Max temperature",
          "schema": "double"
        },
        {
          "name": "minTemp",
          "displayName": "Min temperature",
          "schema": "double"
        },
        {
          "name" : "avgTemp",
          "displayName": "Average Temperature",
          "schema": "double"
        },
        {
          "name" : "startTime",
          "displayName": "Start Time",
          "schema": "dateTime"
        },
        {
          "name" : "endTime",
          "displayName": "End Time",
          "schema": "dateTime"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

deviceClient.subscribeToDeviceMethod(new GetMaxMinReportMethodCallback(), "getMaxMinReport", new MethodIotHubEventCallback(), "getMaxMinReport");

// ...

private static class GetMaxMinReportMethodCallback implements DeviceMethodCallback {
    String commandName = "getMaxMinReport";

    @Override
    public DeviceMethodData call(String methodName, Object methodData, Object context) {

        String jsonRequest = new String((byte[]) methodData, StandardCharsets.UTF_8);
        Date since = gson.fromJson(jsonRequest, Date.class);

        String responsePayload = String.format(
                "{\"maxTemp\": %.1f, \"minTemp\": %.1f, \"avgTemp\": %.1f, \"startTime\": \"%s\", \"endTime\": \"%s\"}",
                maxTemp,
                minTemp,
                avgTemp,
                since,
                endTime);

        return new DeviceMethodData(StatusCode.COMPLETED.value, responsePayload);
    }
}

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

const modelIdObject = { modelId: 'dtmi:com:example:Thermostat;1' };
const client = Client.fromConnectionString(deviceConnectionString, Protocol);
await client.setOptions(modelIdObject);
await client.open();

提示

对于模块和 IoT Edge,使用 ModuleClient 代替 Client

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则。

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性:

async function sendTelemetry(deviceClient, data, index, componentName) {
  const msg = new Message(data);
  if (!!(componentName)) {
    msg.properties.add(messageSubjectProperty, componentName);
  }
  msg.contentType = 'application/json';
  msg.contentEncoding = 'utf-8';
  await deviceClient.sendEvent(msg);
}

只读属性

从默认组件报告属性不需要任何特殊构造:

const createReportPropPatch = (propertiesToReport) => {
  let patch;
  patch = { };
  patch = propertiesToReport;
  return patch;
};

deviceTwin = await client.getTwin();
patchThermostat = createReportPropPatch({
  maxTempSinceLastReboot: 38.7
});

deviceTwin.properties.reported.update(patchThermostat, function (err) {
  if (err) throw err;
});

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTempSinceLastReboot" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包括标记:

helperCreateReportedPropertiesPatch = (propertiesToReport, componentName) => {
  let patch;
  if (!!(componentName)) {
    patch = { };
    propertiesToReport.__t = 'c';
    patch[componentName] = propertiesToReport;
  } else {
    patch = { };
    patch = propertiesToReport;
  }
  return patch;
};

deviceTwin = await client.getTwin();
patchThermostat1Info = helperCreateReportedPropertiesPatch({
  maxTempSinceLastReboot: 38.7,
}, 'thermostat1');

deviceTwin.properties.reported.update(patchThermostat1Info, function (err) {
  if (err) throw err;
});

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1" : {  
      "__t" : "c",  
      "maxTempSinceLastReboot" : 38.7
     } 
  }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 如果解决方案更新属性,客户端会接收到通知,即在 ClientModuleClient 中的回调。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

如果属性类型为 Object,则服务必须将完整的对象发送到设备,即使它只更新对象字段的子集,也是如此。 设备发送的确认也必须是完整的对象。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

patch = {
  targetTemperature:
    {
      'value': 23.2,
      'ac': 200,  // using HTTP status codes
      'ad': 'reported default value',
      'av': 0  // not read from a desired property
    }
};
deviceTwin.properties.reported.update(patch, function (err) {
  if (err) throw err;
});

使用以下报告属性更新设备孪生:

{
  "reported": {
    "targetTemperature": {
      "value": 23.2,
      "ac": 200,
      "av": 0,
      "ad": "reported default value"
    }
  }
}

若要从嵌套组件报告可写属性,孪生必须包括标记:

patch = {
  thermostat1: {
    '__t' : 'c',
    targetTemperature: {
      'value': 23.2,
      'ac': 200,  // using HTTP status codes
      'ad': 'reported default value',
      'av': 0  // not read from a desired property
    }
  }
};
deviceTwin.properties.reported.update(patch, function (err) {
  if (err) throw err;
});

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 0,
          "ad": "complete"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新后的所需属性,其中包括用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

const propertyUpdateHandler = (deviceTwin, propertyName, reportedValue, desiredValue, version) => {
  const patch = createReportPropPatch(
    { [propertyName]:
      {
        'value': desiredValue,
        'ac': 200,
        'ad': 'Successfully executed patch for ' + propertyName,
        'av': version
      }
    });
  updateComponentReportedProperties(deviceTwin, patch);
};

desiredPropertyPatchHandler = (deviceTwin) => {
  deviceTwin.on('properties.desired', (delta) => {
    const versionProperty = delta.$version;

    Object.entries(delta).forEach(([propertyName, propertyValue]) => {
      if (propertyName !== '$version') {
        propertyUpdateHandler(deviceTwin, propertyName, null, propertyValue, versionProperty);
      }
    });
  });
};

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "targetTemperature": 23.2,
    "$version" : 3
  },
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
  }
}

嵌套组件接收用组件名称包装的所需属性,并且应报告 ack 报告的属性:

const desiredPropertyPatchListener = (deviceTwin, componentNames) => {
  deviceTwin.on('properties.desired', (delta) => {
    Object.entries(delta).forEach(([key, values]) => {
      const version = delta.$version;
      if (!!(componentNames) && componentNames.includes(key)) { // then it is a component we are expecting
        const componentName = key;
        const patchForComponents = { [componentName]: {} };
        Object.entries(values).forEach(([propertyName, propertyValue]) => {
          if (propertyName !== '__t' && propertyName !== '$version') {
            const propertyContent = { value: propertyValue };
            propertyContent.ac = 200;
            propertyContent.ad = 'Successfully executed patch';
            propertyContent.av = version;
            patchForComponents[componentName][propertyName] = propertyContent;
          }
        });
        updateComponentReportedProperties(deviceTwin, patchForComponents, componentName);
      }
      else if  (key !== '$version') { // individual property for root
        const patchForRoot = { };
        const propertyContent = { value: values };
        propertyContent.ac = 200;
        propertyContent.ad = 'Successfully executed patch';
        propertyContent.av = version;
        patchForRoot[key] = propertyContent;
        updateComponentReportedProperties(deviceTwin, patchForRoot, null);
      }
    });
  });
};

组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。

const commandHandler = async (request, response) => {
  switch (request.methodName) {
  
  // ...

  case 'thermostat1*reboot': {
    await response.send(200, 'reboot response');
    break;
  }
  default:
    await response.send(404, 'unknown method');
    break;
  }
};

client.onDeviceMethod('thermostat1*reboot', commandHandler);

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。 下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "getMaxMinReport",
  "displayName": "Get Max-Min report.",
  "description": "This command returns the max, min and average temperature from the specified time to the current time.",
  "request": {
    "name": "since",
    "displayName": "Since",
    "description": "Period to return the max-min report.",
    "schema": "dateTime"
  },
  "response": {
    "name" : "tempReport",
    "displayName": "Temperature Report",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "maxTemp",
          "displayName": "Max temperature",
          "schema": "double"
        },
        {
          "name": "minTemp",
          "displayName": "Min temperature",
          "schema": "double"
        },
        {
          "name" : "avgTemp",
          "displayName": "Average Temperature",
          "schema": "double"
        },
        {
          "name" : "startTime",
          "displayName": "Start Time",
          "schema": "dateTime"
        },
        {
          "name" : "endTime",
          "displayName": "End Time",
          "schema": "dateTime"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

class TemperatureSensor {

  // ...

  getMaxMinReportObject() {
    return {
      maxTemp: this.maxTemp,
      minTemp: this.minTemp,
      avgTemp: this.cumulativeTemperature / this.numberOfTemperatureReadings,
      endTime: (new Date(Date.now())).toISOString(),
      startTime: this.startTime
    };
  }
}

// ...

const deviceTemperatureSensor = new TemperatureSensor();

const commandHandler = async (request, response) => {
  switch (request.methodName) {
  case commandMaxMinReport: {
    console.log('MaxMinReport ' + request.payload);
    await response.send(200, deviceTemperatureSensor.getMaxMinReportObject());
    break;
  }
  default:
    await response.send(404, 'unknown method');
    break;
  }
};

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

模型 ID 公告

若要公布模型 ID,设备必须将其包含在连接信息中:

device_client = IoTHubDeviceClient.create_from_symmetric_key(
    symmetric_key=symmetric_key,
    hostname=registration_result.registration_state.assigned_hub,
    device_id=registration_result.registration_state.device_id,
    product_info=model_id,
)

提示

对于模块和 IoT Edge,使用 IoTHubModuleClient 代替 IoTHubDeviceClient

提示

设备只有这一次机会设置模型 ID,设备连接后将无法更新模型 ID。

DPS 有效负载

使用设备预配服务 (DPS) 的设备可以包含要在使用以下 JSON 有效负载的预配过程中使用的 modelId

{
    "modelId" : "dtmi:com:example:Thermostat;1"
}

使用组件

了解 IoT 即插即用模型中的组件一文中所述,设备构建者必须决定是否要使用组件来描述其设备。 使用组件时,设备必须遵循以下各部分所述的规则。

遥测

默认组件不需要向遥测消息添加任何特殊属性。

使用嵌套组件时,设备必须使用组件名称设置消息属性:

async def send_telemetry_from_temp_controller(device_client, telemetry_msg, component_name=None):
    msg = Message(json.dumps(telemetry_msg))
    msg.content_encoding = "utf-8"
    msg.content_type = "application/json"
    if component_name:
        msg.custom_properties["$.sub"] = component_name
    await device_client.send_message(msg)
}

只读属性

从默认组件报告属性不需要任何特殊构造:

await device_client.patch_twin_reported_properties({"maxTempSinceLastReboot": 38.7})

使用以下报告属性更新设备孪生:

{
  "reported": {
      "maxTempSinceLastReboot" : 38.7
  }
}

使用嵌套组件时,属性必须在组件名称中创建并包括标记:

inner_dict = {}
inner_dict["targetTemperature"] = 38.7
inner_dict["__t"] = "c"
prop_dict = {}
prop_dict["thermostat1"] = inner_dict

await device_client.patch_twin_reported_properties(prop_dict)

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1" : {  
      "__t" : "c",  
      "maxTempSinceLastReboot" : 38.7
     }
  }
}

可写属性

这些属性可以由设备设置或通过解决方案更新。 如果解决方案更新属性,客户端会接收到通知,即在 IoTHubDeviceClientIoTHubModuleClient 中的回调。 若要遵循 IoT 即插即用约定,设备必须通知服务属性已成功接收。

如果属性类型为 Object,则服务必须将完整的对象发送到设备,即使它只更新对象字段的子集,也是如此。 设备发送的确认也必须是完整的对象。

报告可写属性

设备报告可写属性时,必须包含约定中定义的 ack 值。

从默认组件报告可写属性:

prop_dict = {}
prop_dict["targetTemperature"] = {
    "ac": 200,
    "ad": "reported default value",
    "av": 0,
    "value": 23.2
}

await device_client.patch_twin_reported_properties(prop_dict)

使用以下报告属性更新设备孪生:

{
  "reported": {
    "targetTemperature": {
      "value": 23.2,
      "ac": 200,
      "av": 0,
      "ad": "reported default value"
    }
  }
}

若要从嵌套组件报告可写属性,孪生必须包括标记:

inner_dict = {}
inner_dict["targetTemperature"] = {
    "ac": 200,
    "ad": "reported default value",
    "av": 0,
    "value": 23.2
}
inner_dict["__t"] = "c"
prop_dict = {}
prop_dict["thermostat1"] = inner_dict

await device_client.patch_twin_reported_properties(prop_dict)

使用以下报告属性更新设备孪生:

{
  "reported": {
    "thermostat1": {
      "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 0,
          "ad": "complete"
      }
    }
  }
}

订阅所需的属性更新

服务可以更新所需的属性,从而在连接的设备上触发通知。 此通知包括更新后的所需属性,其中包括用于标识更新的版本号。 设备必须在发送回服务的 ack 消息中包含此版本号。

默认组件会查看单个属性,并使用收到的版本创建报告的 ack

async def execute_property_listener(device_client):
    ignore_keys = ["__t", "$version"]
    while True:
        patch = await device_client.receive_twin_desired_properties_patch()  # blocking call

        version = patch["$version"]
        prop_dict = {}

        for prop_name, prop_value in patch.items():
            if prop_name in ignore_keys:
                continue
            else:
                prop_dict[prop_name] = {
                    "ac": 200,
                    "ad": "Successfully executed patch",
                    "av": version,
                    "value": prop_value,
                }

        await device_client.patch_twin_reported_properties(prop_dict)

嵌套组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "targetTemperature": 23.2,
    "$version" : 3
  },
  "reported": {
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
  }
}

嵌套组件接收用组件名称包装的所需属性,并且应报告 ack 报告的属性:

def create_reported_properties_from_desired(patch):
    ignore_keys = ["__t", "$version"]
    component_prefix = list(patch.keys())[0]
    values = patch[component_prefix]

    version = patch["$version"]
    inner_dict = {}

    for prop_name, prop_value in values.items():
        if prop_name in ignore_keys:
            continue
        else:
            inner_dict["ac"] = 200
            inner_dict["ad"] = "Successfully executed patch"
            inner_dict["av"] = version
            inner_dict["value"] = prop_value
            values[prop_name] = inner_dict

    properties_dict = dict()
    if component_prefix:
        properties_dict[component_prefix] = values
    else:
        properties_dict = values

    return properties_dict

async def execute_property_listener(device_client):
    while True:
        patch = await device_client.receive_twin_desired_properties_patch()  # blocking call
        properties_dict = create_reported_properties_from_desired(patch)

        await device_client.patch_twin_reported_properties(properties_dict)

组件的设备孪生显示了所需部分和报告部分,如下所示:

{
  "desired" : {
    "thermostat1" : {
        "__t" : "c",
        "targetTemperature": 23.2,
    }
    "$version" : 3
  },
  "reported": {
    "thermostat1" : {
        "__t" : "c",
      "targetTemperature": {
          "value": 23.2,
          "ac": 200,
          "av": 3,
          "ad": "complete"
      }
    }
  }
}

命令

默认组件接收服务调用的命令名称。

嵌套组件接收带有组件名称和 * 分隔符前缀的命令名称。

command_request = await device_client.receive_method_request("thermostat1*reboot")

请求和响应有效负载

命令使用类型定义其请求和响应有效负载。 设备必须反序列化传入的输入参数并串行化响应。 下面的示例演示如何实现具有在有效负载中定义的复杂类型的命令:

{
  "@type": "Command",
  "name": "getMaxMinReport",
  "displayName": "Get Max-Min report.",
  "description": "This command returns the max, min and average temperature from the specified time to the current time.",
  "request": {
    "name": "since",
    "displayName": "Since",
    "description": "Period to return the max-min report.",
    "schema": "dateTime"
  },
  "response": {
    "name" : "tempReport",
    "displayName": "Temperature Report",
    "schema": {
      "@type": "Object",
      "fields": [
        {
          "name": "maxTemp",
          "displayName": "Max temperature",
          "schema": "double"
        },
        {
          "name": "minTemp",
          "displayName": "Min temperature",
          "schema": "double"
        },
        {
          "name" : "avgTemp",
          "displayName": "Average Temperature",
          "schema": "double"
        },
        {
          "name" : "startTime",
          "displayName": "Start Time",
          "schema": "dateTime"
        },
        {
          "name" : "endTime",
          "displayName": "End Time",
          "schema": "dateTime"
        }
      ]
    }
  }
}

下面的代码片段演示了设备如何实现此命令定义,其中包括用于启用序列化和反序列化的类型:

def create_max_min_report_response(values):
    response_dict = {
        "maxTemp": max_temp,
        "minTemp": min_temp,
        "avgTemp": sum(avg_temp_list) / moving_window_size,
        "startTime": (datetime.now() - timedelta(0, moving_window_size * 8)).isoformat(),
        "endTime": datetime.now().isoformat(),
    }
    # serialize response dictionary into a JSON formatted str
    response_payload = json.dumps(response_dict, default=lambda o: o.__dict__, sort_keys=True)
    return response_payload

提示

请求和响应名称不存在于通过网络传输的串行化有效负载中。

后续步骤

知悉,你已经了解了 IoT 即插即用设备开发,下面是一些额外的资源: