CODEWITHSUNDEEP
jsonarduinomqttesp8266nodemcu
Timmo
Timmo

Reputation: 2334

ESP8266 - PubSubClient - Message character limit

I am unable to send messages over a certain limit. I have looked at the docs and have already tried to redefine the max packet size:

#define MQTT_MAX_PACKET_SIZE 512

I've even tried increasing the limit to ridiculous limits and still the message is ignored. The size of my message is 253 characters in compressed JSON format:

{ "code_gc": [ 38000,1,69,342,171,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,63,21,21,21,21,21,21,21,63,21,63,21,63,21,63,21,63,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,21,63,21,63,21,63,21,1829,342,85,21,3663 ] }

It's an IR remote for anyone wondering what I'm building.

Does anyone have any ideas on what I should do to allow this message through? My only thought now is to scrap MQTT and create a REST server, which I don't want to do as MQTT is a lot faster in my experience..

Upvotes: 3

Views: 2887

Answers (2)

Hamed
Hamed

Reputation: 1156

To change this value you can use this two solution

first, define MQTT_MAX_PACKET_SIZE before including SubPubClient

this code in SubPubClint.h, case prioritize your define variable

#ifndef MQTT_MAX_PACKET_SIZE
#define MQTT_MAX_PACKET_SIZE 255
#endif

second, and better solution is use this function to reset buffer size (default value is 255)

boolean PubSubClient::setBufferSize(uint16_t size)

like it :

mqtt.setBufferSize(newBufferValue);

Upvotes: 1

Timmo
Timmo

Reputation: 2334

As I was advised by the repository owner of PubSubClient, I needed to change the MQTT_MAX_PACKET_SIZE inside the source file of PubSubClient as it cannot be redefined.

This fixed my issue.

Upvotes: 2

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