COAP Observe option with COAP get request in nRF5 SDK with openthrea

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Mon, 08 May 2023 15:01:41 GMT

I have verified that COAP server which is running on OTBR is sending data to an end device whenever the observed resource is modified but somehow callback on the end device is not triggering. Please see the last two lines:

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Mon, 08 May 2023 14:57:50 GMT

I am using the built-in COAP APIs of Openthread.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Susheel Nuguru — Mon, 08 May 2023 13:13:06 GMT

I do not have a first hand experience in this but it seems that it is definitely supported in Zephyr CoAP API: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.3.0/zephyr/connectivity/networking/api/coap.html

And the IoT SDK CoAP library in nRF5 SDK: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/lib_iot_coap_addon_observe.html?cp=9_5_1_3_24_1_2_1_0

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Fri, 05 May 2023 15:24:56 GMT

is COAP observe support only available in nRF5 SDK for thread as mentioned here:

devzone.nordicsemi.com/.../coap-observe-with-thread-sdk

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Fri, 05 May 2023 15:03:47 GMT

We are getting a response fro our COAP server after sending observe request to the server that the device is added to the observers list but not getting updates after that. I think the callback is not triggering. Please check this:

static void coap_get_handler(void                * p_context,
                                 otMessage           * p_message,
                                 const otMessageInfo * p_message_info,
                                 otError              aResult)
{
    (void)p_context;
    (void)p_message;
    (void)p_message_info;
    char     config[1024];
    uint16_t config_length = 0;

    uint16_t lenght = otMessageRead(p_message, otMessageGetOffset(p_message), config, 1024);
    config[lenght] = '\0';
    NRF_LOG_INFO("Received CoAP message: %s\r\n", config);
}

/** @COAP Get Request from EMQX Serve.
 */
 void send_coap_get_request(void)
{
    char            payload_buffer[128];
    otError         error;
    otMessage     * p_request;
    otMessageInfo   message_info;
    otInstance    * p_instance = thread_ot_instance_get();

    if (m_associated == false)
    {
        return;
    }

    do
    {
        NRF_LOG_INFO("Sending CoAP Get Request\r\n");
        p_request = otCoapNewMessage(p_instance, NULL);
        if (p_request == NULL)
        {
            NRF_LOG_INFO("Failed to allocate message for CoAP Request\r\n");
            break;
        }

        otCoapMessageGenerateToken(p_request, 4);
        otCoapMessageInit(p_request, OT_COAP_TYPE_NON_CONFIRMABLE, OT_COAP_CODE_GET);
        
     
        error = otCoapMessageAppendObserveOption(p_request, 0);
        NRF_LOG_INFO("otCoapMessageAppendObserveOption erro: %d\r\n", error);
        ASSERT(error == OT_ERROR_NONE);

         error = otCoapMessageAppendUriPathOptions(p_request, CLOUD_URI_PATH2);
         ASSERT(error == OT_ERROR_NONE);


        error = otCoapMessageSetPayloadMarker(p_request);
        ASSERT(error == OT_ERROR_NONE);

        memset(&message_info, 0, sizeof(message_info));
        message_info.mPeerPort = OT_DEFAULT_COAP_PORT;

        error = otIp6AddressFromString(GCP_COAP_IOT_CORE_SERVER_ADDRESS, &message_info.mPeerAddr);
        ASSERT(error == OT_ERROR_NONE);

        
        
        error = otCoapSendRequest(p_instance, p_request, &message_info, coap_get_handler, p_instance);
        if ((error == OT_ERROR_NONE))
        NRF_LOG_INFO("Sent CoAP Request\r\n");

    } while (false);

    if ((error != OT_ERROR_NONE) && (p_request != NULL))
    {
        NRF_LOG_INFO("Failed to send CoAP Request: %d\r\n", error);
        otMessageFree(p_request);
    }
}

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Achim Kraus — Fri, 14 Apr 2023 06:48:59 GMT

And which implementation does your server use?

And it may be the same answer, check the server's API doc how to use the RFC7641 function, guess this extension is supported.

Maybe it's a good idea, to start with a coap-server and coap-client, which is known as working and working demos are provided. At least in my experience, it's always a good idea to reduce the "risk of failures" by starting using "known working components" and then replace, step by stop the working components with the intended components.

If you're able to capture the traffic on one of the nodes (see my tutorial IP capturing , requires to run unix at one of the nodes) and provide the capture (NO pictures!) here, I will have a look in it.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Thu, 13 Apr 2023 20:52:38 GMT

I am able to resolve above issue and not getting any error.

but I am not observing resource values on nRF52840 after resource values change on the COAP server.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Achim Kraus — Thu, 13 Apr 2023 16:41:28 GMT

I guess you need to read the API doc (even if I'm not common to that specific API).

Especially "tiny C" implementations of coap need to assemble the message in the right order. That follows usually RFC 7252 - 3 Message Format . Very rough create the message with the type and code, add token, add options (in order of the option number, see IANA CoAP option numbers ) and then the payload starting with the payload marker. But that's just an assumption, you need to read the API docu.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Thu, 13 Apr 2023 15:16:32 GMT

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Thu, 13 Apr 2023 15:10:46 GMT

Hi,

this is the error number I am getting with otCoapMessageAppendObserveOption.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Susheel Nuguru — Wed, 12 Apr 2023 14:37:03 GMT

If you have a another ticket discussing the same thing, then you should close one of these. Maybe we can close this ticket.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Susheel Nuguru — Wed, 12 Apr 2023 14:36:26 GMT

Can you try to use otCoapMessageAppendObserveOption() instead?

If that does not help then like Achim Kraus mentioned, you need to provide us the error number and/or context of this happening.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Achim Kraus — Wed, 12 Apr 2023 13:10:23 GMT

Just as hint:

The assert reports on "main.c: 109", but only you know, which line in your snippet above is the 109. Maybe you add that as comment into the snippet.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Wed, 12 Apr 2023 12:08:58 GMT

I am getting same response to my other tickets also.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

Susheel Nuguru — Wed, 12 Apr 2023 12:04:18 GMT

I am not sure, I have asked my colleagues to help understanding the failure from the assert context. Will update this thread once I hear from them.

RE: COAP Observe option with COAP get request in nRF5 SDK with openthrea

BilalAliAhmad — Sun, 09 Apr 2023 12:01:18 GMT

I want to make coap request similar to this request which I made through coap-client libcoap example from openthread coap end device: