Struct PublishBuilder 

pub struct PublishBuilder<'a> {
    cmd_tx: &'a Sender<Command>,
    topic: TopicBuf,
    payload: Vec<u8>,
    qos: QoS,
    retain: bool,
    properties: PublishProperties,
}

Builder for publishing a message with optional MQTT v5 properties.

Obtained via MqttClient::publish. Call send to enqueue the message (non-async, returns immediately) or send_async to wait for command queue space.

Fields

cmd_tx: &'a Sender<Command>

topic: TopicBuf

payload: Vec<u8>

qos: QoS

retain: bool

properties: PublishProperties

Implementations

impl<'a> PublishBuilder<'a>

pub(crate) fn new( cmd_tx: &'a Sender<Command>, topic: TopicBuf, payload: Vec<u8>, ) -> Self

pub const fn qos(self, qos: QoS) -> Self

Set the Quality of Service level.

pub const fn retain(self, retain: bool) -> Self

Set the retain flag.

pub fn content_type(self, ct: MqttString) -> Self

Set the MIME content type (property 0x03).

pub fn response_topic(self, topic: TopicBuf) -> Self

Set the response topic for request/response flows (property 0x08).

pub fn correlation_data(self, data: MqttBytesBuf) -> Self

Set correlation data for request/response flows (property 0x09).

pub const fn message_expiry(self, seconds: u32) -> Self

Set the message expiry interval in seconds (property 0x02).

pub const fn payload_format(self, format: PayloadFormat) -> Self

Indicate whether the payload is UTF-8 encoded (property 0x01).

pub fn user_property(self, key: MqttString, value: MqttString) -> Self

Add a user property key-value pair (property 0x26). May be called multiple times.

pub fn send(self) -> Result<PublishToken, Error>

Enqueue the publish (non-blocking).

Returns a PublishToken that can be used to track progress and await the broker acknowledgement.

Errors

Returns Error::ConnectionClosed if the internal command queue is full or the connection has been shut down.

pub async fn send_async(self) -> Result<PublishToken, Error>

Enqueue the publish, waiting for queue space if necessary.

Like send but applies back-pressure instead of failing when the queue is full.

Errors

Returns Error::ConnectionClosed if the connection has been shut down.