How to set RETAIN publish message for flutter Mqtt_client

Question

Now I can publish message using this

MqttServerClient client = MqttServerClient.withPort(broker, "", 1883); //connect broker

//create message
final builder = MqttClientPayloadBuilder();
builder.addString(message);

client.publishMessage(topic, MqttQos.atLeastOnce, builder.payload); //publish message

but how can I set published message to Retain.

I believe that `client.publishMessage(topic, MqttQos.atLeastOnce, builder.payload, true);` is what you are looking for ([docs](https://pub.dev/documentation/mqtt_client/latest/mqtt_client/MqttClient/publishMessage.html)). — Brits, Feb 25 '22 at 23:29

score 0 · Accepted Answer · answered Feb 26 '22 at 04:02

As per the docs the syntax is:

int publishMessage(

    String topic,
    MqttQos qualityOfService,
    Uint8Buffer data,
    {bool retain = false}

)

So your publish would need to be:

client.publishMessage(topic, MqttQos.atLeastOnce, builder.payload, true);

How to set RETAIN publish message for flutter Mqtt_client

1 Answers1