Struct Querier

pub struct Querier<'a> { /* private fields */ }

A querier that allows to send queries to a queryable.

Queriers are automatically undeclared when dropped.

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression").await.unwrap();
let replies = querier.get().await.unwrap();

Implementations

impl<'a> Querier<'a>

pub fn id(&self) -> EntityGlobalId

Available on crate feature unstable only.

Returns the EntityGlobalId of this Querier.

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

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression")
    .await
    .unwrap();
let querier_id = querier.id();

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

Returns the KeyExpr this querier sends queries on.

pub fn congestion_control(&self) -> CongestionControl

Get the congestion_control applied when routing the data.

pub fn priority(&self) -> Priority

Get the priority of the written data.

pub fn accept_replies(&self) -> ReplyKeyExpr

Available on crate feature unstable only.

Get type of queryables that can reply to this querier

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

pub fn get(&self) -> QuerierGetBuilder<'_, '_, DefaultHandler>

Send a query.

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression").await.unwrap();
let replies = querier.get();

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

Undeclare the Querier, informing the network that it needn’t optimize queries for its key expression anymore.

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression").await.unwrap();
querier.undeclare().await.unwrap();

pub fn matching_status(&self) -> impl Resolve<ZResult<MatchingStatus>> + '_

Return the MatchingStatus of the querier.

MatchingStatus::matching will return true if there exist Queryables matching the Queriers’s key expression and target and false otherwise.

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression").await.unwrap();
let matching_queriers: bool = querier
    .matching_status()
    .await
    .unwrap()
    .matching();

pub fn matching_listener(&self) -> MatchingListenerBuilder<'_, DefaultHandler>

Return a MatchingListener for this Querier.

The MatchingListener that will send a notification each time the MatchingStatus of the Querier changes.

Examples

let session = zenoh::open(zenoh::Config::default()).await.unwrap();
let querier = session.declare_querier("key/expression").await.unwrap();
let matching_listener = querier.matching_listener().await.unwrap();
while let Ok(matching_status) = matching_listener.recv_async().await {
    if matching_status.matching() {
        println!("Querier has matching queryables.");
    } else {
        println!("Querier has NO MORE matching queryables.");
    }
}

Trait Implementations

impl<'a> Debug for Querier<'a>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Querier<'_>

fn drop(&mut self)

Executes the destructor for this type.