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use crate::{Config, MqttError};
use rumqttc::{AsyncClient, Event, Packet};
/// Create a persistent session on the MQTT server `config.host`.
///
/// The session is named after the `config.session_name`
/// subscribing to all the topics given by the `config.subscriptions`.
///
/// A new `Connection` created with a config with the same session name,
/// will receive all the messages published meantime on the subscribed topics.
///
/// This function can be called multiple times with the same session name,
/// since it consumes no messages.
pub async fn init_session(config: &Config) -> Result<(), MqttError> {
if config.clean_session || config.session_name.is_none() {
return Err(MqttError::InvalidSessionConfig);
}
let mqtt_options = config.mqtt_options();
let (mqtt_client, mut event_loop) = AsyncClient::new(mqtt_options, config.queue_capacity);
loop {
match event_loop.poll().await {
Ok(Event::Incoming(Packet::ConnAck(ack))) => {
if let Some(err) = MqttError::maybe_connection_error(&ack) {
return Err(err);
};
let subscriptions = config.subscriptions.filters();
if subscriptions.is_empty() {
break;
}
mqtt_client.subscribe_many(subscriptions).await?;
}
Ok(Event::Incoming(Packet::SubAck(_))) => {
break;
}
Err(err) => {
eprintln!("Connection Error {}", err);
break;
}
_ => (),
}
}
// Errors on disconnect are ignored, since having no impact on the session
let _ = mqtt_client.disconnect().await;
Ok(())
}
/// Clear a persistent session on the MQTT server `config.host`.
///
/// The session named after the `config.session_name` is cleared
/// unsubscribing to all the topics given by the `config.subscriptions`.
///
/// All the messages persisted for that session all cleared.
/// and no more messages will be stored till the session is re-created.
///
/// A new `Connection` created with a config with the same session name,
/// will receive no messages that have been published meantime.
pub async fn clear_session(config: &Config) -> Result<(), MqttError> {
if config.session_name.is_none() {
return Err(MqttError::InvalidSessionConfig);
}
let mut mqtt_options = config.mqtt_options();
mqtt_options.set_clean_session(true);
let (mqtt_client, mut event_loop) = AsyncClient::new(mqtt_options, config.queue_capacity);
loop {
match event_loop.poll().await {
Ok(Event::Incoming(Packet::ConnAck(ack))) => {
if let Some(err) = MqttError::maybe_connection_error(&ack) {
return Err(err);
};
break;
}
Err(err) => {
eprintln!("Connection Error {}", err);
break;
}
_ => (),
}
}
// Errors on disconnect are ignored, since having no impact on the session
let _ = mqtt_client.disconnect().await;
Ok(())
}
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