CCS/CC3220SF: Azure IoT Connection using MQTT_Webscoket or HTTP_Protocol with Message Properties

Yavor Arnaudov

Part Number: CC3220SF

Tool/software: Code Composer Studio

Can you provide an example of connecting to the Azure IoT Hub using:

1) MQTT_Websocket_Protocol (port 443)

I tried substitute the transport protocol in the "iothub_clinet_sample_mqtt" from "MQTT_Protocol" to "MQTT_WebSocket_Protocol".
I added the "iothubtransportmqtt_websockets.c" and "http_proxy_io.c" files to the sample.
No communication is established with the IoTHub in either direction.

OR

2) provide workaround for the HTTP_Protocol to receive IoTHub messages with their message properties

Problem lies in "simplelink_cc32xx_sdk_3_20_00_06\source\ti\net\http\httpclient.c"
The http_client allows only the hashed response headers to be stored. The Iot-Hub sends the message properties as part of the response headers in the form { iothub-app-Status: Active }. These get discarded at the http_client level.

over 6 years ago

0 Gerardo Gomez Martinez over 6 years ago

TI__Expert 5825 points

Hello,

The Azure IoT Plugin currently doesn't support MQTT over Websockets.

We are going to investigate the issues of the message properties getting dropped. I will reply back with my findings.

Thanks,
Gerardo

0 Yavor Arnaudov over 6 years ago in reply to Gerardo Gomez Martinez

Prodigy 30 points

Hi Gerado,

What we have found is that the message properties sent from the Azure IoTHub in the http response headers are blocked at:
Snippet from httpclient.c, row:1114:

resNum = resHeaderNameToHash(tmpPtr);
 if (resNum == HEADER_NOT_SUPPORTED)
 {
    continue;
 }
 if (validateResponseHeader(resNum,tmpPtr))

This allows only for the predefined headers to go through:
Snippet from httpclient.c, row:53:

static const char * headerFieldStr[] = {

"Age",

"Allow",

"Cache-Control",

"Connection",

"Content-Encoding",

I hope this helps.

Greetings,
Yavor

0 Gerardo Gomez Martinez over 6 years ago in reply to Yavor Arnaudov

TI__Expert 5825 points

Hi Yarov,

Thank you for giving such a detailed description. I looked into this, and unfortunately the HTTP client currently doesn't support custom headers in HTTP responses. Therefore message properties are currently not working, and there's no easy workaround for this. I filed a bug to fix this, it can be referenced by the bug ID: AZUREIOT-62

Thanks,
Gerardo

0 Yavor Arnaudov over 6 years ago in reply to Gerardo Gomez Martinez

Prodigy 30 points

Hi Gerado,

Where can I track the status of the bug ?

https://cqweb.ext.ti.com/
Does not give any updates until it is solved, which is not sufficient.

Regards,

Yavor

0 Gerardo Gomez Martinez over 6 years ago in reply to Yavor Arnaudov

TI__Expert 5825 points

Hi Yavor,

You can track the bug here:
https://cqweb.ext.ti.com/cqweb/restapi/SDO-Web/SDOWP/RECORD/AZUREIOT-62?cqtoken=d4bffef8-f9b8-48f1-a1a3-976ace915532&loginId=readonly&noframes=true&format=HTML&recordType=IncidentReport

The Status of the bug will be updated when there's changes to it.

Thanks,
Gerardo

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CCS/CC3220SF: Azure IoT Connection using MQTT_Webscoket or HTTP_Protocol with Message Properties