NRF Cloud multiple data points in one massage

Question

Hello, 
 I edded the multi cloud serves to fit my needes. When the divice sends GNSS data after fix it looks like this: 
 "Received":{4 items
 "messageType":"DATA"
 "appId":"GNSS"
 "data":{3 items
 "lat":51.832831879576325
 "lng":4.849055562212727
 "acc":9.889153480529785
 }
 "ts":1723624845580
} 
 When a massage is sent from temperature if I remember it correctly (now it is V for voltage) it looks like this: 
 "Received":{4 items
 "messageType":"DATA"
 "appId":"V"
 "data":38.413185119628906
 "ts":1723624845562
} 
 I removed the queueing application and have another way to handle the not send messages. 
 static int send_sensor_sample(const char *const sensor, double value){
	int ret;
	MSG_OBJ_DEFINE(msg_obj);

	ret = create_timestamped_device_message(&msg_obj, sensor, NRF_CLOUD_JSON_MSG_TYPE_VAL_DATA);
	if (ret) {
 return -EINVAL;
	}
	
	/* Populate the container object with the sensor value. */
	ret = nrf_cloud_obj_num_add(&msg_obj, NRF_CLOUD_JSON_DATA_KEY, value, false);
	if (ret) {
 LOG_ERR("Failed to append value to %s sample container object ",
 sensor);
 nrf_cloud_obj_free(&msg_obj);
 return -ENOMEM;
	}

	int err = nrf_cloud_coap_obj_send(&msg_obj, IS_ENABLED(CONFIG_COAP_SEND_CONFIRMABLE));
	if (err < 0) {
 LOG_ERR("Failed to send %s sample, error: %d", sensor, err);
 return err;
	}
} 
 I call this function a few times and every time the data is put in its own massage. Now I want to add all data in one massage somewhat like the GNSS data. I tried calling nrf_cloud_obj_num_add() multiple times and using nrf_cloud_obj_str_array_add() with a return err that it can't encode unknown type. 
 Can someone help me further?

justin_nordic · Accepted Answer

You can send a "bulk" message, which is just a JSON array of JSON messages. See the function details for nrf_cloud_coap_obj_send . Below is an example of how it could be used in the multi-service sample. 
 A minor modification to the create_timestamped_device_message() function... CBOR encoding does not support bulk messages, so JSON will need to be used. Include the "messageType" field so the message conforms to the schema . /* Create message object: CBOR encoding does not require the message type */
err = nrf_cloud_obj_msg_init(msg, appid,
 msg->type == NRF_CLOUD_OBJ_TYPE_COAP_CBOR ? NULL : msg_type);
if (err) {
	LOG_ERR("Failed to initialize message with appid %s and msg type %s",
 appid, msg_type);
	return err;
} 
 Modifications to build a bulk JSON message: static int send_sensor_sample(const char *const sensor, double value)
{
	int ret;

NRF_CLOUD_OBJ_JSON_DEFINE(bulk_obj);
	NRF_CLOUD_OBJ_JSON_DEFINE(msg_obj);
	NRF_CLOUD_OBJ_JSON_DEFINE(another_msg_obj);

/* Create a timestamped message container object for the sensor sample. */
	ret = create_timestamped_device_message(&msg_obj, sensor,
 NRF_CLOUD_JSON_MSG_TYPE_VAL_DATA);
	if (ret) {
 return -EINVAL;
	}

/* Populate the container object with the sensor value. */
	ret = nrf_cloud_obj_num_add(&msg_obj, NRF_CLOUD_JSON_DATA_KEY, value, false);
	if (ret) {
 LOG_ERR("Failed to append value to %s sample container object ", sensor);
 nrf_cloud_obj_free(&msg_obj);
 return -ENOMEM;
	}

/* Create another message... */
	ret = create_timestamped_device_message(&another_msg_obj, "mySensor",
 NRF_CLOUD_JSON_MSG_TYPE_VAL_DATA);
	if (ret) {
 return -EINVAL;
	}

/* Add data... */
	ret = nrf_cloud_obj_num_add(&another_msg_obj, NRF_CLOUD_JSON_DATA_KEY, 123.456, false);
	if (ret) {
 nrf_cloud_obj_free(&msg_obj);
 nrf_cloud_obj_free(&another_msg_obj);
 return -ENOMEM;
	}

/* Init the bulk container */
	ret = nrf_cloud_obj_bulk_init(&bulk_obj);
	if (ret) {
 goto bulk_err_exit;
	}

/* Add msg_obj to the bulk container */
	ret = nrf_cloud_obj_bulk_add(&bulk_obj, &msg_obj);
	if (ret) {
 goto bulk_err_exit;
	}
	/* Item now belongs to the bulk container */
	(void)nrf_cloud_obj_reset(&msg_obj);

/* Add another_msg_obj to the bulk container */
	ret = nrf_cloud_obj_bulk_add(&bulk_obj, &another_msg_obj);
	if (ret) {
 goto bulk_err_exit;
	}
	/* Item now belongs to the bulk container */
	(void)nrf_cloud_obj_reset(&another_msg_obj);

/* Send the sensor sample container object as a device message. */
	return send_device_message(&bulk_obj);

bulk_err_exit:
	LOG_ERR("Error building bulk message: %d", ret);
	nrf_cloud_obj_free(&msg_obj);
	nrf_cloud_obj_free(&bulk_obj);
	nrf_cloud_obj_free(&another_msg_obj);
	return ret;
} For CoAP, the nrf_cloud_coap_obj_send() function automatically handles the bulk message. 
 The resulting bulk message looks like: [
 {
 "appId": "TEMP",
 "messageType": "DATA",
 "ts": 1723842519683,
 "data": 23.775
 },
 {
 "appId": "mySensor",
 "messageType": "DATA",
 "ts": 1723842519683,
 "data": 123.456
 }
]

NRF Cloud multiple data points in one massage

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