Struct FetchingSubscriber

pub struct FetchingSubscriber<Handler> { /* private fields */ }

👎Deprecated: Use AdvancedPublisher and AdvancedSubscriber instead.

A Subscriber that will run the given user defined fetch function at startup.

This API has been marked as unstable: it works as advertised, but it may be changed in a future release.

The user defined fetch function should fetch some samples and return them through the callback function (it could typically be a Session::get()). Those samples will be merged with the received publications and made available in the receiver. Later on, new fetches can be performed again, calling FetchingSubscriber::fetch().

A typical usage of the FetchingSubscriber is to retrieve publications that were made in the past, but stored in some zenoh Storage.

Examples

use zenoh::Wait;
use zenoh_ext::*;

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let subscriber = session
    .declare_subscriber("key/expr")
    .fetching( |cb| {
        session
            .get("key/expr")
            .callback(cb)
            .wait()
    })
    .await
    .unwrap();
while let Ok(sample) = subscriber.recv_async().await {
    println!("Received: {:?}", sample);
}

Implementations

impl<Handler> FetchingSubscriber<Handler>

pub fn undeclare(self) -> impl Resolve<ZResult<()>>

👎Deprecated: Use AdvancedPublisher and AdvancedSubscriber instead.

Undeclare this FetchingSubscriber`.

This API has been marked as unstable: it works as advertised, but it may be changed in a future release.

pub fn key_expr(&self) -> &KeyExpr<'static>

👎Deprecated: Use AdvancedPublisher and AdvancedSubscriber instead.

Return the key expression of this FetchingSubscriber

This API has been marked as unstable: it works as advertised, but it may be changed in a future release.

pub fn fetch<Fetch: FnOnce(Box<dyn Fn(TryIntoSample) + Send + Sync>) -> ZResult<()> + Send + Sync, TryIntoSample>( &self, fetch: Fetch, ) -> impl Resolve<ZResult<()>>

where TryIntoSample: ExtractSample + Send + Sync,

👎Deprecated: Use AdvancedPublisher and AdvancedSubscriber instead.

Perform an additional fetch.

This API has been marked as unstable: it works as advertised, but it may be changed in a future release.

The provided fetch function should fetch some samples and return them through the callback function (it could typically be a Session::get()). Those samples will be merged with the received publications and made available in the receiver.

Examples

use zenoh::Wait;
use zenoh_ext::*;

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let mut subscriber = session
    .declare_subscriber("key/expr")
    .fetching( |cb| {
        session
            .get("key/expr")
            .callback(cb)
            .wait()
    })
    .await
    .unwrap();

// perform an additional fetch
subscriber
    .fetch( |cb| {
        session
            .get("key/expr")
            .callback(cb)
            .wait()
    })
    .await
    .unwrap();

Trait Implementations

impl<Handler> Deref for FetchingSubscriber<Handler>

type Target = Handler

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<Handler> DerefMut for FetchingSubscriber<Handler>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.