使用REST api向设备发送云消息Azure IoT Hub，endpoint

Question

我试图使用Azure IoT中心和REST api（不使用Azure IoT中心python SDK）从云向我的设备发送消息。

我可以通过urihttps：//成功地从设备向集线器发送消息（POST请求）

我还是尝试了以下方法：

curl -v POST \
  https://<myhub>.azure-devices.net/messages/devicebound?api-version=2018-06-30 \
  -H 'Authorization: SharedAccessSignature <sas>' \
  -H 'Content-Type: application/json' \
  -d '{
    "payload": {
      "key": "value"
    }
  }'

其中通过Azure CLIaz iot hub生成sas令牌-n生成

{"Message":"ErrorCode:ArgumentInvalid;Request must contain IoTHub custom 'To' header","ExceptionMessage":"Tracking ID:ec98ff8...

在那里我切断了末端。所以我尝试添加一个“To”头，不管我放什么，它都会返回相同的错误消息。

我还尝试了此处建议的云到设备Azure IoT REST API，即通过endpointhttps://main.iothub.ext.azure.com/api/Service/SendMessage/发送，但运气不佳。




Answer 1

以下是如何做到这一点：

>

在SendCloudToDeviceMessage.py文件的开头添加以下导入语句和变量：

import random
import sys
import iothub_service_client
from iothub_service_client import IoTHubMessaging, IoTHubMessage, IoTHubError

OPEN_CONTEXT = 0
FEEDBACK_CONTEXT = 1
MESSAGE_COUNT = 1
AVG_WIND_SPEED = 10.0
MSG_TXT = "{\"service client sent a message\": %.2f}"

CONNECTION_STRING = "{IoTHubConnectionString}"
DEVICE_ID = "{deviceId}"

def open_complete_callback(context):
    print ( 'open_complete_callback called with context: {0}'.format(context) )

def send_complete_callback(context, messaging_result):
    context = 0
    print ( 'send_complete_callback called with context : {0}'.format(context) )
    print ( 'messagingResult : {0}'.format(messaging_result) )

def iothub_messaging_sample_run():
    try:
        iothub_messaging = IoTHubMessaging(CONNECTION_STRING)

        iothub_messaging.open(open_complete_callback, OPEN_CONTEXT)

        for i in range(0, MESSAGE_COUNT):
            print ( 'Sending message: {0}'.format(i) )
            msg_txt_formatted = MSG_TXT % (AVG_WIND_SPEED + (random.random() * 4 + 2))
            message = IoTHubMessage(bytearray(msg_txt_formatted, 'utf8'))

            # optional: assign ids
            message.message_id = "message_%d" % i
            message.correlation_id = "correlation_%d" % i
            # optional: assign properties
            prop_map = message.properties()
            prop_text = "PropMsg_%d" % i
            prop_map.add("Property", prop_text)

            iothub_messaging.send_async(DEVICE_ID, message, send_complete_callback, i)

        try:
            # Try Python 2.xx first
            raw_input("Press Enter to continue...\n")
        except:
            pass
            # Use Python 3.xx in the case of exception
            input("Press Enter to continue...\n")

        iothub_messaging.close()

    except IoTHubError as iothub_error:
        print ( "Unexpected error {0}" % iothub_error )
        return
    except KeyboardInterrupt:
        print ( "IoTHubMessaging sample stopped" )

if __name__ == '__main__':
    print ( "Starting the IoT Hub Service Client Messaging Python sample..." )
    print ( "    Connection string = {0}".format(CONNECTION_STRING) )
    print ( "    Device ID         = {0}".format(DEVICE_ID) )

    iothub_messaging_sample_run()

保存并关闭SendCloudToDeviceMessage。py文件。

安装依赖项库：pip安装azure iothub服务客户端

运行应用程序：python SendCloudToDeviceMessage。py

参考：https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/iot-hub/iot-hub-python-python-c2d.md

Answer 2

要使用IoT Hub API从设备端接收云到设备消息，您必须执行以下请求-

curl -X GET \
  'https://{your hub}.azure-devices.net/devices/{your device id}/messages/deviceBound?api-version=2018-06-30' \
  -H 'Authorization: {your sas token}'