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Visitor II
December 31, 2019
Question

Lwip MQTT can't publish a message payload more than 232 Characters

  • December 31, 2019
  • 2 replies
  • 1978 views

Hi all, Iam trying to send a long payload message in a single buffer (const char*) to Mqtt server. Iam using Lwip Mqtt from http://www.nongnu.org/lwip/2_0_x/group__mqtt.html

It worked with payload that fewer than 232 characters. As we know the limit for mqtt payload lenght is 65536.

I tried to compare the result by publish random data (2898 characters) using mosquitto (installed in my pc), it is successfully done.

Any idea how to solve this problem?

Regards

    This topic has been closed for replies.

    2 replies

    Visitor II
    January 4, 2020

    has anyone faced the same problem?

    or maybe it's a new bug?

    i tried it on Nucleo F7 and discovery F4, but still get the same result.

    Visitor II
    September 29, 2020

    Hi, open the header file with name mqtt_opts.h and edit the following sections i.e. 1024 Byte

    #define MQTT_OUTPUT_RINGBUF_SIZE 1024