Message length limit when publishing

[mikycol]

Through the sketch in the library I'm trying to publish the following message {"unique_id": "TAVERNETTA-temperature","device_class": "temperature", "name": "TAVERNETTA Temperature", "state_topic": "homeassistant/sensor/TAVERNETTA/state", "unit_of_measurement": "°C", "value_template": "{{ value_json.temperature}}"}, but the message that arrives is truncated with a length of 147 characters.

I'm pretty sure I made some mistakes, but I can't figure it out.

Any suggestions?

[gak]

I'm having a similar issue, but it's only sending 89 chars. It's on an ESP32-S2. Using 2.4.2 installed via the Arduino IDE.

If I set QoS to 1 or 2, it fails to send at all.

char encoded[2000];

// Some JSON generation here.
// I've tried this with just creating a long string by hand, e.g.:
// char *encoded = "very long string";
// with exactly the same truncation.

Serial.println(motion_config_topic.c_str());
Serial.println(encoded);
Serial.println(strlen(encoded));

if (!messages->publish(motion_config_topic.c_str(), encoded, 0)) {
    Serial.println("Failed to send motion config.");
}

The related output:

16:50:01.893 -> homeassistant/binary_sensor/esp32s2-0edc60-motion/config
16:50:01.893 -> {"name":"esp32s2-0edc60","unique_id":"esp32s2-0edc60-motion","device_class":"motion","state_topic":"homeassistant/binary_sensor/esp32s2-0edc60-motion/state"}
16:50:01.893 -> 157

I've successfully sent a longer message using using another MQTT client. I've received the truncation using two separate clients (home assistant and a rust app). Here is the truncated message for completeness:

{"name":"esp32s2-0edc60","unique_id":"esp32s2-0edc60-motion","device_class":"motion","sta

[gak]

Increasing MAXBUFFERSIZE does the trick. Not sure how stable this solution is but it works for me so far.

Edit: Still had issues. Went with https://github.com/plapointe6/EspMQTTClient which allows changing the max packet size and worked first go.

[SaberShip]

I have this exact issue, seems to always send 88 characters for me before truncating my message. Seems like a pretty big issue.

[MEHUL95]

Exactly same issue, I am facing. Now moving back to move to pubsub client lib again.

[jsphuebner]

Increasing MAXBUFFERSIZE also "fixed" it for me. Should be configurable or larger in the first place, maybe depending on platform.