MQTT support streaming large payload

[leox]

Hi,

nRF9160 examples in NCS, the MQTT publish payload now with a pre allocated buffer,  is it possible to support streaming payload to save memory usage for large payload publish.

Q1: does current NCS release (modem firmware 1.2.3, or 1.3.0) support publish >20KBytes payload in 1 single message?

Q2: is it possible to publish >20K bytes with data streaming to socket instead with pre allocated buffer in RAM?

[leox]

Thanks,

One more questions on the large data upload options.

Do you know any limitations with HTTP or HTTPS to stream large payloads (over 20K) to server with current NCS libraries/examples.

[Didrik Rokhaug]

Looking at Zephyr's HTTP client library, it seems it is able to stream large payloads by using a callback function to request data.

You can see the API in action in Zephyr's http_client sample https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.0/zephyr/samples/net/sockets/http_client/README.html

Note that the sample has not been tested on the nRF9160, and might need some modifications to run on the nRF9160.