payload len on received topics via MQTTSN and Thread

Question

HI, 
 I am trying to read the payload length of the data coming in a topic via MQTTSN over OpenThread. In the event handler, I am getting the event and trying to get the length from it: 
 
 void mqttsn_evt_handler ( mqttsn_client_t * p_client , mqttsn_event_t * p_event ) 
 { 
 ....

switch ( p_event -> event_id ) 
 { 
 ....

case MQTTSN_EVENT_RECEIVED : 
 NRF_LOG_DEBUG ( "MQTT-SN event: Client received content. 
 " );

At this point, I am expecting the length to be in: 
 
 p_event->event_data.published.packet.len 
 
 but this is always 0. I guess this is also the incorrect place to check for the *payload* length, this looks more like the entire packet length. I could not find other member that might resemble a length. 
 Is there any other place where the payload length might be read from? This seems to be an important check in making sure I am parsing correctly the data coming from MQTTSN. 
 Regards, 
 Edgar

Jørgen Holmefjord · Answer

Hi, 
 It seems like the payload length is not assigned to the member of the structure passed to the MQTT-SN event handler. 
 You can forward the payload length from function publish_handle() in mqttsn_packet_receiver.c by adding the following after line 442: 
 evt.event_data.published.packet.len = payload_len; 
 This should be the message payload length, and not the full packet length. 
 Best regards, Jørgen

payload len on received topics via MQTTSN and Thread

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