Struct nats::jetstream::push_subscription::PushSubscription

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pub struct PushSubscription(_);

Expand description

A PushSubscription receives Messages published to specific NATS Subjects.

Implementations

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Attach a closure to handle messages. This closure will execute in a separate thread. The result of this call is a Handler which can not be iterated and must be unsubscribed or closed directly to unregister interest. A Handler will not unregister interest with the server when drop(&mut self) is called.

Example

context.subscribe("with_handler")?.with_handler(move |message| {
    println!("received {}", &message);
    Ok(())
});

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pub fn with_process_handler<F>(self, handler: F) -> Handler where
F: Fn(&Message) -> Result<()> + Send + 'static,

Attach a closure to process and acknowledge messages. This closure will execute in a separate thread.

The result of this call is a Handler which can not be iterated and must be unsubscribed or closed directly to unregister interest. A Handler will not unregister interest with the server when drop(&mut self) is called.

Example

context.subscribe("with_process_handler")?.with_process_handler(|message| {
    println!("Received {}", &message);

    Ok(())
});

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pub fn process<R, F: Fn(&Message) -> Result<R>>(&mut self, f: F) -> Result<R>

Process and acknowledge a single message, waiting indefinitely for one to arrive.

Does not acknowledge the processed message if the closure returns an Err.

Example

let mut subscription = context.subscribe("process")?;
subscription.process(|message| {
    println!("Received message {:?}", message);

    Ok(())
})?;

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pub fn process_timeout<R, F: Fn(&Message) -> Result<R>>(
 &mut self,
 timeout: Duration,
 f: F
) -> Result<R>

Process and acknowledge a single message, waiting up to timeout configured timeout before returning a timeout error.

Does not ack the processed message if the internal closure returns an Err.

Example

let mut subscription = context.subscribe("process_timeout")?;
subscription.process_timeout(std::time::Duration::from_secs(1), |message| {
    println!("Received message {:?}", message);

    Ok(())
})?;

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pub fn consumer_info(&self) -> Result<ConsumerInfo>

Sends a request to fetch current information about the target consumer.

Example

let subscription = context.subscribe("foo")?;
let info = subscription.consumer_info()?;

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pub fn unsubscribe(self) -> Result<()>

Unsubscribe a subscription immediately without draining. Use drain instead if you want any pending messages to be processed by a handler, if one is configured.

Example

let subscription = context.subscribe("unsubscribe")?;
subscription.unsubscribe()?;

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pub fn close(self) -> Result<()>

Close a subscription. Same as unsubscribe

Use drain instead if you want any pending messages to be processed by a handler, if one is configured.

Example

let subscription = context.subscribe("close")?;
subscription.close()?;

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pub fn drain(&self) -> Result<()>

Send an unsubscription and flush the connection, allowing any unprocessed messages to be handled by a Subscription

After the flush returns, we know that a round-trip to the server has happened after it received our unsubscription, so we shut down the subscriber afterwards.

A similar method exists on the Connection struct which will drain all subscriptions for the NATS client, and transition the entire system into the closed state afterward.

Example

let mut subscription = context.subscribe("drain")?;

context.publish("drain", "foo")?;
context.publish("drain", "bar")?;
context.publish("drain", "baz")?;

subscription.drain()?;

assert!(subscription.next().is_some());