How to use postman to test send data to iot central

Question

How to use postman to test send data to iot central

Feiling Pan 40

I don't know how to operate, maybe it needs middleware or something else, I have tried to use function and so on as middleware delivery, but it doesn't seem to work. I wish someone could teach me step by step. I've been doing this for a long time.

LeelaRajeshSayana-MSFT 17,766 Moderator

Hi @Feiling Pan](/users/na/?userid=edb7c8f1-ba37-411d-b8ef-6ba0f1379ece) Greetings! Welcome to Microsoft Q&A forum. We would be glad to assist you with this request.

The IoT Central Device API provides different endpoints that enable us to update properties of a device on IoT Central. Please refer the following methods for reference.

Update Relationship Patch a given relationship given the relationship ID and a given device ID.

Update	Update a device via patch
Update Attestation	Update an individual device attestation via patch
Update Component Properties	Update device properties for a specific component via patch
Update Module Component Properties	Update module properties for a specific component via patch
Update Module Properties	Update module properties via patch
Update Properties	Update device properties via patch
Update Relationship	Patch a given relationship given the relationship ID and a given device ID.

Update Relationship Patch a given relationship given the relationship ID and a given device ID.

Have you tried using the Update properties method and to send data to IoT Central? The API needs a Bearer token for authentication which can be obtained executing the command az account get-access-token --resource https://apps.azureiotcentral.com from Azure shell.

Please note that it might be easier to simulate data using an SDK instead of postman. If you prefer to simulate data using a .Net SDK, please refer the post How to generate custom telemetry string data for a simulated device sensor in IoT Central where a solution to this has been shared.

Please let us know if you have any additional questions on this.

LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-13T19:09:26.1633333+00:00

Hi @Feiling Pan Greetings! I am following up to see if you got a chance to review the below response. Please let us know if you have any additional questions or need further assistance.

If the response helped, please do click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.

Accepted answer

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LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-12T23:28:31.8366667+00:00

Hi @Feiling Pan](/users/na/?userid=edb7c8f1-ba37-411d-b8ef-6ba0f1379ece) Greetings! Welcome to Microsoft Q&A forum. We would be glad to assist you with this request.

The IoT Central Device API provides different endpoints that enable us to update properties of a device on IoT Central. Please refer the following methods for reference.

Update Relationship Patch a given relationship given the relationship ID and a given device ID.

Update Update a device via patch

Update Attestation Update an individual device attestation via patch

Update Component Properties Update device properties for a specific component via patch

Update Module Component Properties Update module properties for a specific component via patch

Update Module Properties Update module properties via patch

Update Properties Update device properties via patch

Update Relationship Patch a given relationship given the relationship ID and a given device ID.

Update Relationship Patch a given relationship given the relationship ID and a given device ID.

Have you tried using the Update properties method and to send data to IoT Central? The API needs a Bearer token for authentication which can be obtained executing the command az account get-access-token --resource https://apps.azureiotcentral.com from Azure shell.

Please note that it might be easier to simulate data using an SDK instead of postman. If you prefer to simulate data using a .Net SDK, please refer the post How to generate custom telemetry string data for a simulated device sensor in IoT Central where a solution to this has been shared.

Please let us know if you have any additional questions on this.
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-13T19:09:26.1633333+00:00

Hi @Feiling Pan Greetings! I am following up to see if you got a chance to review the below response. Please let us know if you have any additional questions or need further assistance.

If the response helped, please do click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.

Answer 1

Roman Kiss 2,246

Hi @Feiling Pan ,

Azure IoT Hub allows to send an event (device telemetry data) via the REST POST request, see more details here.

In the case of Azure IoT Central, you have to obtain a fully-qualified-iothubname its underlying Azure IoT Hub (cluster) using a DPS service, for instance using the Azure portal CLI commands.

The following are steps to get the assignedHub and the device sas token:

Getting the assignedHub:

az iot device registration create --id-scope {id_scope} --rid {device_id} --key {symmetric_key}

Getting the device sas token:

az iot hub generate-sas-token --connection-string 'HostName={assignedHub};DeviceId={device_id};SharedAccessKey={symmetric_key}'

Once you have the assignedHub and the device sas token, you can use the Postman for sending the telemetry data to the Azure IoT Central its underlying assignedHub:

https://{assignedHub}/devices/{device_id}/messages/events?api-version=2021-04-12

Authorization:{sas}

Note, that the values of id_scope, device_id and symetric_key are from your Azure IoT Central App.

Also, you can create an Azure function to replace the above steps, see more details here.

Thanks

Roman

Feiling Pan 40 Reputation points

2023-06-14T14:12:35.4333333+00:00

Thanks for your reply, my first step went well. I used the sas of the central device as the key, but managed to get fully qualified-iothubname, but the second step kept telling me that the connection string was not in the right format. I used the azure module in vscode to generate the sas token, but postman returned 401.

I think it might be because my hub and central aren't connected? Could you tell me how to connect hub and central? By the way, where is the correct symmetric_key, since I'm using the device's sas primary key(but success).
Feiling Pan 40 Reputation points

2023-06-14T14:20:25.0933333+00:00

Thanks about all
Roman Kiss 2,246 Reputation points

2023-06-14T14:45:25.78+00:00

The following screen snippet shows a page of the IoT Central App, where you can get the id_scope, device_id and symetric_key:
Feiling Pan 40 Reputation points

2023-06-15T10:31:54.44+00:00

Thanks, I think I use the right one, but the second step it says the connection string's format not right.
Roman Kiss 2,246 Reputation points

2023-06-15T11:17:56.12+00:00

Try to use an Azure portal, see my example:

az iot hub generate-sas-token --connection-string 'HostName=iotc-01234.azure-devices.net;DeviceId=device123;SharedAccessKey=000='
Dominic 1,631 Reputation points Microsoft Employee

2023-06-15T11:53:08.74+00:00

After you've followed Roman's instructions to generate the token - you can use this simple Postman collection to try it out: https://gist.github.com/dominicbetts/810ae328287a502f2eb32af33b63afa3
Feiling Pan 40 Reputation points

2023-06-15T12:58:04.5866667+00:00

OH MY GOD IT WORKS! Thank you very much to help me solve this problem!!!!!!!
Dominic 1,631 Reputation points Microsoft Employee

2023-06-15T13:15:52.97+00:00

For reference, there's a discussion here about the differences between using HTTP, MQTT, and AMQP to connect a device to IoT Hub (or IoT Central): https://learn.microsoft.com/en-usazure/iot-hub/iot-hub-devguide-protocols
LeelaRajeshSayana-MSFT 17,766 Reputation points Moderator

2023-06-15T13:18:22.7133333+00:00

Hello @Feiling Pan Glad to know you could use the API successfully. I appreciate it if you click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.
Feiling Pan 40 Reputation points

2023-06-15T14:36:05.6066667+00:00

Last question, my project is to use the phone to receive the data from the Bluetooth device and then send it to iot central. But sas acquired in this way seems to expire after a few hours, is there any way to get long-term authorization?

Answer 2

Dominic 1,631 Microsoft Employee

There are multiple guides and a sample Postman file that illustrate most of the IoT Central REST API here:

There's a link to download the Postman collection in each of these articles.

Feiling Pan 40 Reputation points

2023-06-14T14:28:02.9933333+00:00

Thank you for your reply. Now I want to make a mobile app to send the Bluetooth data read to iot central. But these documents don't seem to have that capability.

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How to use postman to test send data to iot central

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