First Pub/Sub

Now that you have the basics, let's build a complete pub/sub example with typed payloads.

Typed Publisher with CDR Serialisation

Zenoh payloads are raw bytes — you choose your serialisation format.

use zenoh::prelude::*;
use serde::{Deserialize, Serialize};
 
#[derive(Serialize, Deserialize, Debug)]
struct SensorReading {
    sensor_id: u32,
    temperature: f32,
    timestamp_ms: u64,
}
 
#[tokio::main]
async fn main() {
    let session = zenoh::open(zenoh::config::default()).await.unwrap();
    let publisher = session
        .declare_publisher("sensors/temperature/**")
        .await
        .unwrap();
 
    let reading = SensorReading {
        sensor_id: 42,
        temperature: 23.5,
        timestamp_ms: 1_700_000_000_000,
    };
 
    let payload = serde_json::to_vec(&reading).unwrap();
    publisher.put(payload).await.unwrap();
    println!("Published: {:?}", reading);
}

Subscriber with Deserialisation

#[tokio::main]
async fn main() {
    let session = zenoh::open(zenoh::config::default()).await.unwrap();
    let subscriber = session
        .declare_subscriber("sensors/**")
        .await
        .unwrap();
 
    while let Ok(sample) = subscriber.recv_async().await {
        let payload = sample.payload().to_bytes();
        if let Ok(reading) = serde_json::from_slice::<SensorReading>(&payload) {
            println!("[{}] temp = {}°C", reading.sensor_id, reading.temperature);
        }
    }
}

Key Takeaways

Key expressions are hierarchical paths — use ** as a wildcard matching any number of path segments
Publishers declare their intent once; sending is just put(payload)
Subscribers filter by key expression — they receive all matching publications
Location transparency: the publisher and subscriber do not know about each other

You're ready to explore Core Concepts.